fallow_api/

audit_keys.rs

use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use std::path::Path;

use rustc_hash::{FxHashMap, FxHashSet};

use fallow_config::{ResolvedConfig, Severity};
use fallow_types::envelope::AuditIntroduced;
use fallow_types::identity::{IdentifiedFinding, IdentityPaths, dead_code_occurrence_keys};

pub use crate::audit_complexity::{
    ComplexityBaseline, ComplexityMetrics, classify_complexity_findings,
    classify_complexity_findings_against_all, complexity_baseline, complexity_baseline_keys,
    complexity_ledger_keys, remap_complexity_baseline_for_renames,
};

/// One dead-code finding classified for audit comparison.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct AuditFindingRecord {
    /// JSON collection containing the finding.
    pub collection: &'static str,
    /// Stable position inside the collection for typed annotation routing.
    pub ordinal: usize,
    /// Stable cross-run identity used for base comparison.
    pub stable_key: String,
    /// Whether the finding is absent from the base snapshot.
    pub introduced: bool,
    /// Effective rule severity after per-file overrides.
    pub effective_severity: Severity,
}

/// Exhaustive dead-code comparison ledger shared by audit verdict and output.
#[derive(Debug, Clone, Default)]
pub struct DeadCodeAuditLedger {
    records: Vec<AuditFindingRecord>,
    keys: FxHashSet<String>,
    introduced_keys: FxHashSet<String>,
    inherited_keys: FxHashSet<String>,
    #[cfg(test)]
    classifications: usize,
}

impl DeadCodeAuditLedger {
    /// Classified findings in deterministic output order.
    #[must_use]
    pub fn records(&self) -> &[AuditFindingRecord] {
        &self.records
    }

    /// Stable current-run key set for cache snapshots and graph hashes.
    #[must_use]
    pub const fn keys(&self) -> &FxHashSet<String> {
        &self.keys
    }

    #[cfg(test)]
    const fn classification_count(&self) -> usize {
        self.classifications
    }

    /// Number of visible findings introduced since the base snapshot.
    #[must_use]
    pub fn introduced_count(&self) -> usize {
        self.introduced_keys.len()
    }

    /// Number of counted findings whose effective severity is not off.
    /// Advisory prop chains remain available in the records.
    #[must_use]
    pub fn visible_count(&self) -> usize {
        self.records
            .iter()
            .filter(|record| {
                record.effective_severity != Severity::Off
                    && (record.collection != "prop_drilling_chains"
                        || record.effective_severity == Severity::Error)
            })
            .count()
    }

    /// Number of visible findings inherited from the base snapshot.
    #[must_use]
    pub fn inherited_count(&self) -> usize {
        self.inherited_keys.len()
    }

    /// Whether an introduced finding has effective error severity.
    #[must_use]
    pub fn has_introduced_errors(&self) -> bool {
        self.records
            .iter()
            .any(|record| record.introduced && record.effective_severity == Severity::Error)
    }

    /// Whether an introduced finding has effective warning severity.
    #[must_use]
    pub fn has_introduced_warnings(&self) -> bool {
        self.records
            .iter()
            .any(|record| record.introduced && record.effective_severity == Severity::Warn)
    }

    /// Demote introduced findings that have no syntactic counterpart in the
    /// current head run to inherited (advisory) status.
    ///
    /// Used by the audit's degraded type-aware path: when base and head
    /// semantic identities cannot be compared, attribution diffs the
    /// pre-refinement syntactic key sets. A head finding absent from its own
    /// syntactic set exists only because of semantic evidence and cannot be
    /// attributed against a syntactic base, so it must not fail the new-only
    /// gate. Findings present syntactically keep their classification, so a
    /// genuinely new syntactic finding still gates.
    pub fn demote_unattributable_introductions(&mut self, head_syntactic: &FxHashSet<String>) {
        for record in &mut self.records {
            if record.introduced && !head_syntactic.contains(&record.stable_key) {
                record.introduced = false;
                self.introduced_keys.remove(&record.stable_key);
                if record.effective_severity != Severity::Off
                    && (record.collection != "prop_drilling_chains"
                        || record.effective_severity == Severity::Error)
                {
                    self.inherited_keys.insert(record.stable_key.clone());
                }
            }
        }
    }

    /// Persist comparison membership into existing typed output fields.
    ///
    /// `StaleSuppression` is the sole legacy finding without a typed
    /// `introduced` slot. Its serializer keeps a narrow stable-key fallback.
    #[expect(
        clippy::too_many_lines,
        reason = "exhaustive result destructuring and field annotation must stay together so new finding collections require an explicit audit decision"
    )]
    pub fn annotate_results(&self, results: &mut fallow_types::results::AnalysisResults) {
        let fallow_types::results::AnalysisResults {
            unused_files,
            unused_exports,
            unused_types,
            private_type_leaks,
            deprecated_exports_in_use,
            unused_dependencies,
            unused_dev_dependencies,
            unused_optional_dependencies,
            unused_enum_members,
            unused_class_members,
            unused_store_members,
            unresolved_imports,
            unlisted_dependencies,
            duplicate_exports,
            type_only_dependencies,
            test_only_dependencies,
            dev_dependencies_in_production,
            circular_dependencies,
            re_export_cycles,
            package_cycles,
            boundary_violations,
            boundary_coverage_violations,
            boundary_call_violations,
            policy_violations,
            stale_suppressions: _stale_suppressions,
            unused_catalog_entries,
            empty_catalog_groups,
            unresolved_catalog_references,
            unused_dependency_overrides,
            misconfigured_dependency_overrides,
            invalid_client_exports,
            mixed_client_server_barrels,
            misplaced_directives,
            unprovided_injects,
            unrendered_components,
            unused_component_props,
            absent_component_props,
            unused_component_emits,
            unused_component_inputs,
            unused_component_outputs,
            unused_svelte_events,
            unused_effect_layers,
            unused_tagged_errors,
            unproduced_catch_tags,
            unused_server_actions,
            unused_load_data_keys,
            unused_load_data_keys_global_abstain: _unused_load_data_keys_global_abstain,
            route_collisions,
            dynamic_segment_name_conflicts,
            cascade_hidden: _cascade_hidden,
            cascade: _cascade,
            suppression_count: _suppression_count,
            unused_component_props_exempted: _unused_component_props_exempted,
            active_suppressions: _active_suppressions,
            feature_flags: _feature_flags,
            security_findings: _security_findings,
            security_unresolved_edge_files: _security_unresolved_edge_files,
            security_unresolved_callee_sites: _security_unresolved_callee_sites,
            security_unresolved_callee_diagnostics: _security_unresolved_callee_diagnostics,
            prop_drilling_chains,
            thin_wrappers: _thin_wrappers,
            duplicate_prop_shapes: _duplicate_prop_shapes,
            export_usages: _export_usages,
            entry_point_summary: _entry_point_summary,
            render_fan_in: _render_fan_in,
            react_component_intel: _react_component_intel,
            semantic_framework_contracts: _semantic_framework_contracts,
        } = results;

        macro_rules! annotate {
            ($field:ident, $collection:literal) => {
                for (item, introduced) in $field.iter_mut().zip(
                    self.records
                        .iter()
                        .filter(|record| record.collection == $collection)
                        .map(|record| record.introduced),
                ) {
                    item.introduced = Some(AuditIntroduced(introduced));
                }
            };
        }

        annotate!(prop_drilling_chains, "prop_drilling_chains");
        annotate!(unused_files, "unused_files");
        annotate!(unused_exports, "unused_exports");
        annotate!(unused_types, "unused_types");
        annotate!(private_type_leaks, "private_type_leaks");
        annotate!(deprecated_exports_in_use, "deprecated_exports_in_use");
        annotate!(unused_dependencies, "unused_dependencies");
        annotate!(unused_dev_dependencies, "unused_dev_dependencies");
        annotate!(unused_optional_dependencies, "unused_optional_dependencies");
        annotate!(unused_enum_members, "unused_enum_members");
        annotate!(unused_class_members, "unused_class_members");
        annotate!(unused_store_members, "unused_store_members");
        annotate!(unresolved_imports, "unresolved_imports");
        annotate!(unlisted_dependencies, "unlisted_dependencies");
        annotate!(duplicate_exports, "duplicate_exports");
        annotate!(type_only_dependencies, "type_only_dependencies");
        annotate!(test_only_dependencies, "test_only_dependencies");
        annotate!(
            dev_dependencies_in_production,
            "dev_dependencies_in_production"
        );
        annotate!(circular_dependencies, "circular_dependencies");
        annotate!(re_export_cycles, "re_export_cycles");
        annotate!(package_cycles, "package_cycles");
        annotate!(boundary_violations, "boundary_violations");
        annotate!(boundary_coverage_violations, "boundary_coverage_violations");
        annotate!(boundary_call_violations, "boundary_call_violations");
        annotate!(policy_violations, "policy_violations");
        annotate!(unused_catalog_entries, "unused_catalog_entries");
        annotate!(empty_catalog_groups, "empty_catalog_groups");
        annotate!(
            unresolved_catalog_references,
            "unresolved_catalog_references"
        );
        annotate!(unused_dependency_overrides, "unused_dependency_overrides");
        annotate!(
            misconfigured_dependency_overrides,
            "misconfigured_dependency_overrides"
        );
        annotate!(invalid_client_exports, "invalid_client_exports");
        annotate!(mixed_client_server_barrels, "mixed_client_server_barrels");
        annotate!(misplaced_directives, "misplaced_directives");
        annotate!(unprovided_injects, "unprovided_injects");
        annotate!(unrendered_components, "unrendered_components");
        annotate!(route_collisions, "route_collisions");
        annotate!(
            dynamic_segment_name_conflicts,
            "dynamic_segment_name_conflicts"
        );
        annotate!(unused_component_props, "unused_component_props");
        annotate!(absent_component_props, "absent_component_props");
        annotate!(unused_component_emits, "unused_component_emits");
        annotate!(unused_component_inputs, "unused_component_inputs");
        annotate!(unused_component_outputs, "unused_component_outputs");
        annotate!(unused_svelte_events, "unused_svelte_events");
        annotate!(unused_effect_layers, "unused_effect_layers");
        annotate!(unused_tagged_errors, "unused_tagged_errors");
        annotate!(unproduced_catch_tags, "unproduced_catch_tags");
        annotate!(unused_server_actions, "unused_server_actions");
        annotate!(unused_load_data_keys, "unused_load_data_keys");
    }
}

/// Stable-key membership for one non-dead-code audit domain.
#[derive(Debug, Clone, Default)]
pub struct AuditDomainLedger {
    records: Vec<(String, bool)>,
    keys: FxHashSet<String>,
    introduced_keys: FxHashSet<String>,
    inherited_keys: FxHashSet<String>,
    demoted_keys: FxHashSet<String>,
}

impl AuditDomainLedger {
    /// Compare ordered stable keys against an optional base snapshot.
    #[must_use]
    pub fn compare(
        keys: impl IntoIterator<Item = String>,
        base: Option<&FxHashSet<String>>,
    ) -> Self {
        let mut records = Vec::new();
        let mut unique_keys = FxHashSet::default();
        let mut introduced_keys = FxHashSet::default();
        let mut inherited_keys = FxHashSet::default();
        for key in keys {
            let introduced = base.is_some_and(|base| !base.contains(&key));
            if base.is_some() {
                if introduced {
                    introduced_keys.insert(key.clone());
                } else {
                    inherited_keys.insert(key.clone());
                }
            }
            unique_keys.insert(key.clone());
            records.push((key, introduced));
        }
        Self {
            records,
            keys: unique_keys,
            introduced_keys,
            inherited_keys,
            demoted_keys: FxHashSet::default(),
        }
    }

    /// Build a ledger from keys that the caller already classified, in
    /// typed output order. `has_base` is false when the run has no base
    /// snapshot, so no finding counts as introduced or inherited.
    #[must_use]
    pub fn from_classified(
        records: impl IntoIterator<Item = (String, bool)>,
        has_base: bool,
    ) -> Self {
        let mut ledger = Self::default();
        for (key, introduced) in records {
            let introduced = has_base && introduced;
            if has_base {
                if introduced {
                    ledger.introduced_keys.insert(key.clone());
                } else {
                    ledger.inherited_keys.insert(key.clone());
                }
            }
            ledger.keys.insert(key.clone());
            ledger.records.push((key, introduced));
        }
        ledger
    }

    /// Stable current-run key set.
    #[must_use]
    pub const fn keys(&self) -> &FxHashSet<String> {
        &self.keys
    }

    /// Number of introduced findings.
    #[must_use]
    pub fn introduced_count(&self) -> usize {
        self.introduced_keys.len()
    }

    /// Number of inherited findings.
    #[must_use]
    pub fn inherited_count(&self) -> usize {
        self.inherited_keys.len()
    }

    /// Introduced membership in typed output order.
    pub fn introduced(&self) -> impl ExactSizeIterator<Item = bool> + '_ {
        self.records.iter().map(|(_, introduced)| *introduced)
    }

    /// Number of findings demoted from introduced to inherited. Demoted
    /// findings stay counted as inherited, so
    /// `demoted_count() <= inherited_count()` holds by construction.
    #[must_use]
    pub fn demoted_count(&self) -> usize {
        self.demoted_keys.len()
    }

    /// Keys demoted from introduced to inherited by
    /// [`Self::demote_introductions`].
    #[must_use]
    pub const fn demoted_keys(&self) -> &FxHashSet<String> {
        &self.demoted_keys
    }

    /// Demoted membership in typed output order, parallel to
    /// [`Self::introduced`].
    pub fn demoted(&self) -> impl ExactSizeIterator<Item = bool> + '_ {
        self.records
            .iter()
            .map(|(key, _)| self.demoted_keys.contains(key))
    }

    /// Demote introduced findings whose keys are in `demote` to inherited
    /// (advisory) status so they no longer fail the new-only gate. Each key
    /// actually flipped is recorded so output surfaces can report the
    /// demotion (issue #2220).
    pub fn demote_introductions(&mut self, demote: &FxHashSet<String>) {
        for (key, introduced) in &mut self.records {
            if *introduced && demote.contains(key) {
                *introduced = false;
                self.introduced_keys.remove(key);
                self.inherited_keys.insert(key.clone());
                self.demoted_keys.insert(key.clone());
            }
        }
    }
}

/// One-pass audit comparison shared by attribution, verdict, and annotations.
#[derive(Debug, Clone, Default)]
pub struct AuditComparison {
    /// Dead-code finding ledger with effective severity routing.
    pub dead_code: DeadCodeAuditLedger,
    /// Complexity finding membership.
    pub health: AuditDomainLedger,
    /// Duplication group membership.
    pub dupes: AuditDomainLedger,
    /// Styling finding membership.
    pub styling: AuditDomainLedger,
}

/// Remap root-relative path tokens inside base-snapshot attribution keys so a
/// finding on a renamed file matches its base counterpart under the old path.
///
/// `renames` maps base-relative old paths to head-relative new paths, both in
/// [`relative_key_path`] form. Keys embed paths as whole `:`-separated
/// segments, with sorted `|`-separated path lists inside one segment for
/// multi-file findings (duplication groups, circular dependencies, duplicate
/// exports). Segments are remapped only on an exact path match, and
/// multi-path list segments are re-sorted after remapping so they stay
/// canonical. Non-path segments (names, lines, hashes) never collide with a
/// relative path and pass through unchanged.
#[must_use]
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashMap/FxHashSet across audit attribution keys"
)]
pub fn remap_keys_for_renames(
    keys: &FxHashSet<String>,
    renames: &FxHashMap<String, String>,
) -> FxHashSet<String> {
    keys.iter()
        .map(|key| remap_key_for_renames(key, renames))
        .collect()
}

pub(crate) fn remap_key_for_renames(key: &str, renames: &FxHashMap<String, String>) -> String {
    if !key
        .split([':', '|'])
        .any(|segment| renames.contains_key(segment))
    {
        return key.to_string();
    }
    let segments: Vec<String> = key
        .split(':')
        .map(|segment| {
            if segment.contains('|') {
                let mut pieces: Vec<&str> = segment
                    .split('|')
                    .map(|piece| renames.get(piece).map_or(piece, String::as_str))
                    .collect();
                pieces.sort_unstable();
                pieces.dedup();
                pieces.join("|")
            } else {
                renames
                    .get(segment)
                    .cloned()
                    .unwrap_or_else(|| segment.to_string())
            }
        })
        .collect();
    segments.join(":")
}

/// Canonical path form used inside attribution keys. The engine owns the one
/// implementation, because its module-graph maps use the same keys.
pub use fallow_engine::module_graph::relative_key_path;

/// The audit keys of one finding collection, in collection order.
///
/// Each key is the canonical key of the finding (see
/// [`fallow_types::identity`]), so a line shift does not change it. A repeated
/// key gets an occurrence suffix, so the base and the head compare by count:
/// a new second finding with an inherited key is introduced.
fn collection_keys<T: IdentifiedFinding>(items: &[T], root: &Path) -> Vec<String> {
    dead_code_occurrence_keys(items, &IdentityPaths::new(root))
}

/// Build the set of audit attribution keys for all dead-code findings in
/// `results`.
///
/// Each key is a stable string that uniquely identifies one finding across
/// runs (e.g. `unused-file:src/dead.ts`, `unused-export:src/a.ts:Foo`).
/// `retain_introduced_dead_code` and `annotate_dead_code_json` use the same
/// key format to diff the current run against a base snapshot.
///
/// This destructure is deliberately exhaustive: adding a field to
/// `AnalysisResults` must fail compilation here so the author decides
/// explicitly whether the new finding type needs an audit key (add a loop)
/// or has no key representation today (bind with underscore and document why).
///
/// Sibling exhaustive sites: `fallow_engine::changed_files::filter_results_by_changed_files`,
/// The six dependency-related finding slices, bundled so the dependency
/// dispatcher takes one parameter instead of six.
#[derive(Clone, Copy)]
#[allow(
    clippy::struct_field_names,
    reason = "field names mirror the AnalysisResults field names so the destructure stays shorthand"
)]
struct DependencyFindingSlices<'a> {
    unused_dependencies: &'a [fallow_types::output_dead_code::UnusedDependencyFinding],
    unused_dev_dependencies: &'a [fallow_types::output_dead_code::UnusedDevDependencyFinding],
    unused_optional_dependencies:
        &'a [fallow_types::output_dead_code::UnusedOptionalDependencyFinding],
    unlisted_dependencies: &'a [fallow_types::output_dead_code::UnlistedDependencyFinding],
    type_only_dependencies: &'a [fallow_types::output_dead_code::TypeOnlyDependencyFinding],
    test_only_dependencies: &'a [fallow_types::output_dead_code::TestOnlyDependencyFinding],
    dev_dependencies_in_production:
        &'a [fallow_types::output_dead_code::DevDependencyInProductionFinding],
}

/// The six framework-specific finding slices, bundled so the framework
/// dispatcher takes one parameter instead of six.
#[derive(Clone, Copy)]
struct FrameworkFindingSlices<'a> {
    unprovided_injects: &'a [fallow_types::output_dead_code::UnprovidedInjectFinding],
    unrendered_components: &'a [fallow_types::output_dead_code::UnrenderedComponentFinding],
    unused_server_actions: &'a [fallow_types::output_dead_code::UnusedServerActionFinding],
    unused_load_data_keys: &'a [fallow_types::output_dead_code::UnusedLoadDataKeyFinding],
    route_collisions: &'a [fallow_types::output_dead_code::RouteCollisionFinding],
    dynamic_segment_name_conflicts:
        &'a [fallow_types::output_dead_code::DynamicSegmentNameConflictFinding],
}

#[derive(Clone, Copy)]
struct ComponentContractFindingSlices<'a> {
    unused_component_props: &'a [fallow_types::output_dead_code::UnusedComponentPropFinding],
    absent_component_props: &'a [fallow_types::output_dead_code::AbsentComponentPropFinding],
    unused_component_emits: &'a [fallow_types::output_dead_code::UnusedComponentEmitFinding],
    unused_component_inputs: &'a [fallow_types::output_dead_code::UnusedComponentInputFinding],
    unused_component_outputs: &'a [fallow_types::output_dead_code::UnusedComponentOutputFinding],
    unused_svelte_events: &'a [fallow_types::output_dead_code::UnusedSvelteEventFinding],
    unused_effect_layers: &'a [fallow_types::output_dead_code::UnusedEffectLayerFinding],
    unused_tagged_errors: &'a [fallow_types::output_dead_code::UnusedTaggedErrorFinding],
    unproduced_catch_tags: &'a [fallow_types::output_dead_code::UnproducedCatchTagFinding],
}

/// `dead_code_keys`, `retain_introduced_dead_code`.
/// Non-exhaustive siblings the compiler will NOT flag (wire manually when a
/// finding type is added): `annotate_dead_code_json` (same key formats, this
/// file) and the per-collection `off` filter branches in
/// `crates/engine/src/dead_code.rs` (`apply_rule_severities`). The severity of
/// each record comes from the `RuleSeverity` table in
/// `crates/engine/src/effective_severity.rs`, whose visitors are exhaustive.
/// TypeScript mirror: `editors/vscode/scripts/codegen-contracts.mjs` derives
/// backwards-compatible aliases from `fallow schema` `ts_alias` rows.
pub fn dead_code_keys(
    results: &fallow_types::results::AnalysisResults,
    root: &Path,
) -> FxHashSet<String> {
    let mut collector = DeadCodeKeyCollector::new(root);
    collector.add_all_findings(results);
    collector.into_keys()
}

/// Build the exhaustive dead-code comparison ledger once for an audit run.
#[must_use]
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashSet across audit attribution keys"
)]
pub fn dead_code_audit_ledger(
    results: &fallow_types::results::AnalysisResults,
    root: &Path,
    config: &ResolvedConfig,
    base: Option<&FxHashSet<String>>,
) -> DeadCodeAuditLedger {
    let mut collector = DeadCodeKeyCollector::for_comparison(root, config, base);
    collector.add_all_findings(results);
    collector.into_ledger()
}

impl DeadCodeKeyCollector<'_> {
    #[expect(
        clippy::too_many_lines,
        reason = "flat field-by-field destructure of the large AnalysisResults struct (with per-field provenance comments) plus straight-line dispatch; length tracks the field count, not branching"
    )]
    fn add_all_findings(&mut self, results: &fallow_types::results::AnalysisResults) {
        let fallow_types::results::AnalysisResults {
            unused_files,
            unused_exports,
            unused_types,
            private_type_leaks,
            deprecated_exports_in_use,
            unused_dependencies,
            unused_dev_dependencies,
            unused_optional_dependencies,
            unused_enum_members,
            unused_class_members,
            unused_store_members,
            unresolved_imports,
            unlisted_dependencies,
            duplicate_exports,
            type_only_dependencies,
            test_only_dependencies,
            dev_dependencies_in_production,
            circular_dependencies,
            re_export_cycles,
            package_cycles,
            boundary_violations,
            boundary_coverage_violations,
            boundary_call_violations,
            policy_violations,
            stale_suppressions,
            unused_catalog_entries,
            empty_catalog_groups,
            unresolved_catalog_references,
            unused_dependency_overrides,
            misconfigured_dependency_overrides,
            invalid_client_exports,
            mixed_client_server_barrels,
            misplaced_directives,
            unprovided_injects,
            unrendered_components,
            unused_component_props,
            absent_component_props,
            unused_component_emits,
            unused_component_inputs,
            unused_component_outputs,
            unused_svelte_events,
            unused_effect_layers,
            unused_tagged_errors,
            unproduced_catch_tags,
            unused_server_actions,
            unused_load_data_keys,
            unused_load_data_keys_global_abstain: _unused_load_data_keys_global_abstain,
            route_collisions,
            dynamic_segment_name_conflicts,
            // Non-finding fields: counts and metadata, not attributable to a key.
            cascade_hidden: _cascade_hidden,
            cascade: _cascade,
            suppression_count: _suppression_count,
            unused_component_props_exempted: _unused_component_props_exempted,
            active_suppressions: _active_suppressions,
            feature_flags: _feature_flags,
            // Security findings are emitted via `fallow security`, not the audit
            // dead-code gate; they have no dead-code key representation today.
            security_findings: _security_findings,
            security_unresolved_edge_files: _security_unresolved_edge_files,
            security_unresolved_callee_sites: _security_unresolved_callee_sites,
            security_unresolved_callee_diagnostics: _security_unresolved_callee_diagnostics,
            prop_drilling_chains,
            // Thin wrappers are a dormant health signal (rule defaults to `off`); a
            // candidate-for-inlining record, not a dead-code attribution key.
            thin_wrappers: _thin_wrappers,
            // Duplicate prop shapes are a dormant multi-file health signal (rule
            // defaults to `off`); a missing-abstraction record, not a dead-code
            // attribution key.
            duplicate_prop_shapes: _duplicate_prop_shapes,
            // Export usages and entry-point summary are metadata, not issue
            // collections; no key needed.
            export_usages: _export_usages,
            entry_point_summary: _entry_point_summary,
            // Render fan-in is a whole-project descriptive metric, not an issue
            // collection; no attribution key needed.
            render_fan_in: _render_fan_in,
            // Per-component React intel is a descriptive ambient-editor carrier,
            // not an issue collection; no attribution key needed.
            react_component_intel: _react_component_intel,
            semantic_framework_contracts: _semantic_framework_contracts,
        } = results;

        self.add_items(AuditCollection::PropDrillingChains, prop_drilling_chains);
        self.add_core_findings(
            unused_files,
            unused_exports,
            unused_types,
            private_type_leaks,
        );
        self.add_deprecated_exports_in_use(deprecated_exports_in_use);
        self.add_client_directive_findings(
            invalid_client_exports,
            mixed_client_server_barrels,
            misplaced_directives,
        );
        self.add_dependency_findings(&DependencyFindingSlices {
            unused_dependencies,
            unused_dev_dependencies,
            unused_optional_dependencies,
            unlisted_dependencies,
            type_only_dependencies,
            test_only_dependencies,
            dev_dependencies_in_production,
        });
        self.add_dependency_override_findings(
            unused_dependency_overrides,
            misconfigured_dependency_overrides,
        );
        self.add_member_findings(
            unused_enum_members,
            unused_class_members,
            unused_store_members,
        );
        self.add_component_contract_findings(&ComponentContractFindingSlices {
            unused_component_props,
            absent_component_props,
            unused_component_emits,
            unused_component_inputs,
            unused_component_outputs,
            unused_svelte_events,
            unused_effect_layers,
            unused_tagged_errors,
            unproduced_catch_tags,
        });
        self.add_graph_findings(
            unresolved_imports,
            duplicate_exports,
            circular_dependencies,
            re_export_cycles,
            package_cycles,
        );
        self.add_boundary_findings(
            boundary_violations,
            boundary_coverage_violations,
            boundary_call_violations,
            policy_violations,
            stale_suppressions,
        );
        self.add_catalog_findings(
            unresolved_catalog_references,
            unused_catalog_entries,
            empty_catalog_groups,
        );
        self.add_framework_findings(&FrameworkFindingSlices {
            unprovided_injects,
            unrendered_components,
            unused_server_actions,
            unused_load_data_keys,
            route_collisions,
            dynamic_segment_name_conflicts,
        });
    }
}

#[derive(Clone, Copy)]
enum AuditCollection {
    PropDrillingChains,
    UnusedFiles,
    UnusedExports,
    UnusedTypes,
    PrivateTypeLeaks,
    DeprecatedExportsInUse,
    UnusedDependencies,
    UnusedDevDependencies,
    UnusedOptionalDependencies,
    UnusedEnumMembers,
    UnusedClassMembers,
    UnusedStoreMembers,
    UnresolvedImports,
    UnlistedDependencies,
    DuplicateExports,
    TypeOnlyDependencies,
    TestOnlyDependencies,
    DevDependenciesInProduction,
    CircularDependencies,
    ReExportCycles,
    PackageCycles,
    BoundaryViolations,
    BoundaryCoverageViolations,
    BoundaryCallViolations,
    PolicyViolations,
    StaleSuppressions,
    UnusedCatalogEntries,
    EmptyCatalogGroups,
    UnresolvedCatalogReferences,
    UnusedDependencyOverrides,
    MisconfiguredDependencyOverrides,
    InvalidClientExports,
    MixedClientServerBarrels,
    MisplacedDirectives,
    UnprovidedInjects,
    UnrenderedComponents,
    RouteCollisions,
    DynamicSegmentNameConflicts,
    UnusedComponentProps,
    AbsentComponentProps,
    UnusedComponentEmits,
    UnusedComponentInputs,
    UnusedComponentOutputs,
    UnusedSvelteEvents,
    UnusedEffectLayers,
    UnusedTaggedErrors,
    UnproducedCatchTags,
    UnusedServerActions,
    UnusedLoadDataKeys,
}

impl AuditCollection {
    #[cfg(test)]
    const ALL: [Self; 49] = [
        Self::PropDrillingChains,
        Self::UnusedFiles,
        Self::UnusedExports,
        Self::UnusedTypes,
        Self::PrivateTypeLeaks,
        Self::DeprecatedExportsInUse,
        Self::UnusedDependencies,
        Self::UnusedDevDependencies,
        Self::UnusedOptionalDependencies,
        Self::UnusedEnumMembers,
        Self::UnusedClassMembers,
        Self::UnusedStoreMembers,
        Self::UnresolvedImports,
        Self::UnlistedDependencies,
        Self::DuplicateExports,
        Self::TypeOnlyDependencies,
        Self::TestOnlyDependencies,
        Self::DevDependenciesInProduction,
        Self::CircularDependencies,
        Self::ReExportCycles,
        Self::PackageCycles,
        Self::BoundaryViolations,
        Self::BoundaryCoverageViolations,
        Self::BoundaryCallViolations,
        Self::PolicyViolations,
        Self::StaleSuppressions,
        Self::UnusedCatalogEntries,
        Self::EmptyCatalogGroups,
        Self::UnresolvedCatalogReferences,
        Self::UnusedDependencyOverrides,
        Self::MisconfiguredDependencyOverrides,
        Self::InvalidClientExports,
        Self::MixedClientServerBarrels,
        Self::MisplacedDirectives,
        Self::UnprovidedInjects,
        Self::UnrenderedComponents,
        Self::RouteCollisions,
        Self::DynamicSegmentNameConflicts,
        Self::UnusedComponentProps,
        Self::AbsentComponentProps,
        Self::UnusedComponentEmits,
        Self::UnusedComponentInputs,
        Self::UnusedComponentOutputs,
        Self::UnusedSvelteEvents,
        Self::UnusedEffectLayers,
        Self::UnusedTaggedErrors,
        Self::UnproducedCatchTags,
        Self::UnusedServerActions,
        Self::UnusedLoadDataKeys,
    ];

    const fn json_key(self) -> &'static str {
        match self {
            Self::PropDrillingChains => "prop_drilling_chains",
            Self::UnusedFiles => "unused_files",
            Self::UnusedExports => "unused_exports",
            Self::UnusedTypes => "unused_types",
            Self::PrivateTypeLeaks => "private_type_leaks",
            Self::DeprecatedExportsInUse => "deprecated_exports_in_use",
            Self::UnusedDependencies => "unused_dependencies",
            Self::UnusedDevDependencies => "unused_dev_dependencies",
            Self::UnusedOptionalDependencies => "unused_optional_dependencies",
            Self::UnusedEnumMembers => "unused_enum_members",
            Self::UnusedClassMembers => "unused_class_members",
            Self::UnusedStoreMembers => "unused_store_members",
            Self::UnresolvedImports => "unresolved_imports",
            Self::UnlistedDependencies => "unlisted_dependencies",
            Self::DuplicateExports => "duplicate_exports",
            Self::TypeOnlyDependencies => "type_only_dependencies",
            Self::TestOnlyDependencies => "test_only_dependencies",
            Self::DevDependenciesInProduction => "dev_dependencies_in_production",
            Self::CircularDependencies => "circular_dependencies",
            Self::ReExportCycles => "re_export_cycles",
            Self::PackageCycles => "package_cycles",
            Self::BoundaryViolations => "boundary_violations",
            Self::BoundaryCoverageViolations => "boundary_coverage_violations",
            Self::BoundaryCallViolations => "boundary_call_violations",
            Self::PolicyViolations => "policy_violations",
            Self::StaleSuppressions => "stale_suppressions",
            Self::UnusedCatalogEntries => "unused_catalog_entries",
            Self::EmptyCatalogGroups => "empty_catalog_groups",
            Self::UnresolvedCatalogReferences => "unresolved_catalog_references",
            Self::UnusedDependencyOverrides => "unused_dependency_overrides",
            Self::MisconfiguredDependencyOverrides => "misconfigured_dependency_overrides",
            Self::InvalidClientExports => "invalid_client_exports",
            Self::MixedClientServerBarrels => "mixed_client_server_barrels",
            Self::MisplacedDirectives => "misplaced_directives",
            Self::UnprovidedInjects => "unprovided_injects",
            Self::UnrenderedComponents => "unrendered_components",
            Self::RouteCollisions => "route_collisions",
            Self::DynamicSegmentNameConflicts => "dynamic_segment_name_conflicts",
            Self::UnusedComponentProps => "unused_component_props",
            Self::AbsentComponentProps => "absent_component_props",
            Self::UnusedComponentEmits => "unused_component_emits",
            Self::UnusedComponentInputs => "unused_component_inputs",
            Self::UnusedComponentOutputs => "unused_component_outputs",
            Self::UnusedSvelteEvents => "unused_svelte_events",
            Self::UnusedEffectLayers => "unused_effect_layers",
            Self::UnusedTaggedErrors => "unused_tagged_errors",
            Self::UnproducedCatchTags => "unproduced_catch_tags",
            Self::UnusedServerActions => "unused_server_actions",
            Self::UnusedLoadDataKeys => "unused_load_data_keys",
        }
    }
}

struct DeadCodeKeyCollector<'a> {
    root: &'a Path,
    keys: FxHashSet<String>,
    introduced_keys: FxHashSet<String>,
    inherited_keys: FxHashSet<String>,
    records: Vec<AuditFindingRecord>,
    collection_counts: FxHashMap<&'static str, usize>,
    config: Option<&'a ResolvedConfig>,
    base: Option<&'a FxHashSet<String>>,
    #[cfg(test)]
    classifications: usize,
}

impl<'a> DeadCodeKeyCollector<'a> {
    fn new(root: &'a Path) -> Self {
        Self {
            root,
            keys: FxHashSet::default(),
            introduced_keys: FxHashSet::default(),
            inherited_keys: FxHashSet::default(),
            records: Vec::new(),
            collection_counts: FxHashMap::default(),
            config: None,
            base: None,
            #[cfg(test)]
            classifications: 0,
        }
    }

    fn for_comparison(
        root: &'a Path,
        config: &'a ResolvedConfig,
        base: Option<&'a FxHashSet<String>>,
    ) -> Self {
        Self {
            root,
            keys: FxHashSet::default(),
            introduced_keys: FxHashSet::default(),
            inherited_keys: FxHashSet::default(),
            records: Vec::new(),
            collection_counts: FxHashMap::default(),
            config: Some(config),
            base,
            #[cfg(test)]
            classifications: 0,
        }
    }

    fn into_keys(self) -> FxHashSet<String> {
        self.keys
    }

    fn into_ledger(self) -> DeadCodeAuditLedger {
        DeadCodeAuditLedger {
            records: self.records,
            keys: self.keys,
            introduced_keys: self.introduced_keys,
            inherited_keys: self.inherited_keys,
            #[cfg(test)]
            classifications: self.classifications,
        }
    }

    fn insert(&mut self, collection: AuditCollection, key: String, effective_severity: Severity) {
        let collection = collection.json_key();
        let ordinal = self.collection_counts.entry(collection).or_default();
        if self.config.is_some() {
            #[cfg(test)]
            {
                self.classifications += 1;
            }
            let introduced = self.base.is_some_and(|base| !base.contains(&key));
            if effective_severity != Severity::Off
                && self.base.is_some()
                && (collection != "prop_drilling_chains" || effective_severity == Severity::Error)
            {
                if introduced {
                    self.introduced_keys.insert(key.clone());
                } else {
                    self.inherited_keys.insert(key.clone());
                }
            }
            self.records.push(AuditFindingRecord {
                collection,
                ordinal: *ordinal,
                introduced,
                effective_severity,
                stable_key: key.clone(),
            });
        }
        *ordinal += 1;
        self.keys.insert(key);
    }

    /// Insert every finding of one collection under its audit key.
    fn add_items<T>(&mut self, collection: AuditCollection, items: &[T])
    where
        T: IdentifiedFinding + fallow_engine::dead_code::RuleSeverity,
    {
        let keys = collection_keys(items, self.root);
        for (item, key) in items.iter().zip(keys) {
            self.insert_rule(collection, key, item);
        }
    }

    /// Insert a finding with the severity that the shared rule table gives
    /// it. The exit code and the CI formats read the same table.
    fn insert_rule(
        &mut self,
        collection: AuditCollection,
        key: String,
        item: &impl fallow_engine::dead_code::RuleSeverity,
    ) {
        let effective = self.config.map_or(Severity::Off, |config| {
            item.rule_severity(&fallow_engine::dead_code::SeveritySource::from_config(
                config,
            ))
        });
        self.insert(collection, key, effective);
    }

    fn add_core_findings(
        &mut self,
        unused_files: &[fallow_types::output_dead_code::UnusedFileFinding],
        unused_exports: &[fallow_types::output_dead_code::UnusedExportFinding],
        unused_types: &[fallow_types::output_dead_code::UnusedTypeFinding],
        private_type_leaks: &[fallow_types::output_dead_code::PrivateTypeLeakFinding],
    ) {
        self.add_unused_files(unused_files);
        self.add_unused_exports(unused_exports);
        self.add_unused_types(unused_types);
        self.add_private_type_leaks(private_type_leaks);
    }

    fn add_client_directive_findings(
        &mut self,
        invalid_client_exports: &[fallow_types::output_dead_code::InvalidClientExportFinding],
        mixed_client_server_barrels: &[fallow_types::output_dead_code::MixedClientServerBarrelFinding],
        misplaced_directives: &[fallow_types::output_dead_code::MisplacedDirectiveFinding],
    ) {
        self.add_invalid_client_exports(invalid_client_exports);
        self.add_mixed_client_server_barrels(mixed_client_server_barrels);
        self.add_misplaced_directives(misplaced_directives);
    }

    fn add_dependency_findings(&mut self, deps: &DependencyFindingSlices<'_>) {
        let DependencyFindingSlices {
            unused_dependencies,
            unused_dev_dependencies,
            unused_optional_dependencies,
            unlisted_dependencies,
            type_only_dependencies,
            test_only_dependencies,
            dev_dependencies_in_production,
        } = *deps;
        self.add_unused_dependencies(unused_dependencies);
        self.add_unused_dev_dependencies(unused_dev_dependencies);
        self.add_unused_optional_dependencies(unused_optional_dependencies);
        self.add_unlisted_dependencies(unlisted_dependencies);
        self.add_type_only_dependencies(type_only_dependencies);
        self.add_test_only_dependencies(test_only_dependencies);
        self.add_dev_dependencies_in_production(dev_dependencies_in_production);
    }

    fn add_dependency_override_findings(
        &mut self,
        unused_dependency_overrides: &[fallow_types::output_dead_code::UnusedDependencyOverrideFinding],
        misconfigured_dependency_overrides: &[fallow_types::output_dead_code::MisconfiguredDependencyOverrideFinding],
    ) {
        self.add_unused_dependency_overrides(unused_dependency_overrides);
        self.add_misconfigured_dependency_overrides(misconfigured_dependency_overrides);
    }

    fn add_member_findings(
        &mut self,
        unused_enum_members: &[fallow_types::output_dead_code::UnusedEnumMemberFinding],
        unused_class_members: &[fallow_types::output_dead_code::UnusedClassMemberFinding],
        unused_store_members: &[fallow_types::output_dead_code::UnusedStoreMemberFinding],
    ) {
        self.add_unused_enum_members(unused_enum_members);
        self.add_unused_class_members(unused_class_members);
        self.add_unused_store_members(unused_store_members);
    }

    fn add_component_contract_findings(&mut self, components: &ComponentContractFindingSlices<'_>) {
        let ComponentContractFindingSlices {
            unused_component_props,
            absent_component_props,
            unused_component_emits,
            unused_component_inputs,
            unused_component_outputs,
            unused_svelte_events,
            unused_effect_layers,
            unused_tagged_errors,
            unproduced_catch_tags,
        } = *components;
        self.add_unused_component_props(unused_component_props);
        self.add_items(
            AuditCollection::AbsentComponentProps,
            absent_component_props,
        );
        self.add_unused_component_emits(unused_component_emits);
        self.add_unused_component_inputs(unused_component_inputs);
        self.add_unused_component_outputs(unused_component_outputs);
        self.add_unused_svelte_events(unused_svelte_events);
        self.add_unused_effect_layers(unused_effect_layers);
        self.add_unused_tagged_errors(unused_tagged_errors);
        self.add_unproduced_catch_tags(unproduced_catch_tags);
    }

    fn add_graph_findings(
        &mut self,
        unresolved_imports: &[fallow_types::output_dead_code::UnresolvedImportFinding],
        duplicate_exports: &[fallow_types::output_dead_code::DuplicateExportFinding],
        circular_dependencies: &[fallow_types::output_dead_code::CircularDependencyFinding],
        re_export_cycles: &[fallow_types::output_dead_code::ReExportCycleFinding],
        package_cycles: &[fallow_types::output_dead_code::PackageCycleFinding],
    ) {
        self.add_unresolved_imports(unresolved_imports);
        self.add_duplicate_exports(duplicate_exports);
        self.add_circular_dependencies(circular_dependencies);
        self.add_re_export_cycles(re_export_cycles);
        self.add_package_cycles(package_cycles);
    }

    fn add_boundary_findings(
        &mut self,
        boundary_violations: &[fallow_types::output_dead_code::BoundaryViolationFinding],
        boundary_coverage_violations: &[fallow_types::output_dead_code::BoundaryCoverageViolationFinding],
        boundary_call_violations: &[fallow_types::output_dead_code::BoundaryCallViolationFinding],
        policy_violations: &[fallow_types::output_dead_code::PolicyViolationFinding],
        stale_suppressions: &[fallow_types::results::StaleSuppression],
    ) {
        self.add_boundary_violations(boundary_violations);
        self.add_boundary_coverage_violations(boundary_coverage_violations);
        self.add_boundary_call_violations(boundary_call_violations);
        self.add_policy_violations(policy_violations);
        self.add_stale_suppressions(stale_suppressions);
    }

    fn add_catalog_findings(
        &mut self,
        unresolved_catalog_references: &[fallow_types::output_dead_code::UnresolvedCatalogReferenceFinding],
        unused_catalog_entries: &[fallow_types::output_dead_code::UnusedCatalogEntryFinding],
        empty_catalog_groups: &[fallow_types::output_dead_code::EmptyCatalogGroupFinding],
    ) {
        self.add_unresolved_catalog_references(unresolved_catalog_references);
        self.add_unused_catalog_entries(unused_catalog_entries);
        self.add_empty_catalog_groups(empty_catalog_groups);
    }

    fn add_framework_findings(&mut self, framework: &FrameworkFindingSlices<'_>) {
        let FrameworkFindingSlices {
            unprovided_injects,
            unrendered_components,
            unused_server_actions,
            unused_load_data_keys,
            route_collisions,
            dynamic_segment_name_conflicts,
        } = *framework;
        self.add_unprovided_injects(unprovided_injects);
        self.add_unrendered_components(unrendered_components);
        self.add_unused_server_actions(unused_server_actions);
        self.add_unused_load_data_keys(unused_load_data_keys);
        self.add_route_collisions(route_collisions);
        self.add_dynamic_segment_name_conflicts(dynamic_segment_name_conflicts);
    }

    fn add_unused_files(&mut self, items: &[fallow_types::output_dead_code::UnusedFileFinding]) {
        self.add_items(AuditCollection::UnusedFiles, items);
    }

    fn add_unused_exports(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedExportFinding],
    ) {
        self.add_items(AuditCollection::UnusedExports, items);
    }

    fn add_unused_types(&mut self, items: &[fallow_types::output_dead_code::UnusedTypeFinding]) {
        self.add_items(AuditCollection::UnusedTypes, items);
    }

    fn add_private_type_leaks(
        &mut self,
        items: &[fallow_types::output_dead_code::PrivateTypeLeakFinding],
    ) {
        self.add_items(AuditCollection::PrivateTypeLeaks, items);
    }

    fn add_deprecated_exports_in_use(
        &mut self,
        items: &[fallow_types::output_dead_code::DeprecatedExportInUseFinding],
    ) {
        self.add_items(AuditCollection::DeprecatedExportsInUse, items);
    }

    fn add_invalid_client_exports(
        &mut self,
        items: &[fallow_types::output_dead_code::InvalidClientExportFinding],
    ) {
        self.add_items(AuditCollection::InvalidClientExports, items);
    }

    fn add_mixed_client_server_barrels(
        &mut self,
        items: &[fallow_types::output_dead_code::MixedClientServerBarrelFinding],
    ) {
        self.add_items(AuditCollection::MixedClientServerBarrels, items);
    }

    fn add_misplaced_directives(
        &mut self,
        items: &[fallow_types::output_dead_code::MisplacedDirectiveFinding],
    ) {
        self.add_items(AuditCollection::MisplacedDirectives, items);
    }

    fn add_unprovided_injects(
        &mut self,
        items: &[fallow_types::output_dead_code::UnprovidedInjectFinding],
    ) {
        self.add_items(AuditCollection::UnprovidedInjects, items);
    }

    fn add_unrendered_components(
        &mut self,
        items: &[fallow_types::output_dead_code::UnrenderedComponentFinding],
    ) {
        self.add_items(AuditCollection::UnrenderedComponents, items);
    }

    fn add_unused_component_props(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedComponentPropFinding],
    ) {
        self.add_items(AuditCollection::UnusedComponentProps, items);
    }

    fn add_unused_component_emits(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedComponentEmitFinding],
    ) {
        self.add_items(AuditCollection::UnusedComponentEmits, items);
    }

    fn add_unused_component_inputs(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedComponentInputFinding],
    ) {
        self.add_items(AuditCollection::UnusedComponentInputs, items);
    }

    fn add_unused_component_outputs(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedComponentOutputFinding],
    ) {
        self.add_items(AuditCollection::UnusedComponentOutputs, items);
    }

    fn add_unused_svelte_events(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedSvelteEventFinding],
    ) {
        self.add_items(AuditCollection::UnusedSvelteEvents, items);
    }
    fn add_unused_effect_layers(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedEffectLayerFinding],
    ) {
        self.add_items(AuditCollection::UnusedEffectLayers, items);
    }
    fn add_unused_tagged_errors(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedTaggedErrorFinding],
    ) {
        self.add_items(AuditCollection::UnusedTaggedErrors, items);
    }
    fn add_unproduced_catch_tags(
        &mut self,
        items: &[fallow_types::output_dead_code::UnproducedCatchTagFinding],
    ) {
        self.add_items(AuditCollection::UnproducedCatchTags, items);
    }

    fn add_unused_server_actions(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedServerActionFinding],
    ) {
        self.add_items(AuditCollection::UnusedServerActions, items);
    }

    fn add_unused_load_data_keys(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedLoadDataKeyFinding],
    ) {
        self.add_items(AuditCollection::UnusedLoadDataKeys, items);
    }

    fn add_route_collisions(
        &mut self,
        items: &[fallow_types::output_dead_code::RouteCollisionFinding],
    ) {
        self.add_items(AuditCollection::RouteCollisions, items);
    }

    fn add_dynamic_segment_name_conflicts(
        &mut self,
        items: &[fallow_types::output_dead_code::DynamicSegmentNameConflictFinding],
    ) {
        self.add_items(AuditCollection::DynamicSegmentNameConflicts, items);
    }

    fn add_unused_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedDependencyFinding],
    ) {
        self.add_items(AuditCollection::UnusedDependencies, items);
    }

    fn add_unused_dev_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedDevDependencyFinding],
    ) {
        self.add_items(AuditCollection::UnusedDevDependencies, items);
    }

    fn add_unused_optional_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedOptionalDependencyFinding],
    ) {
        self.add_items(AuditCollection::UnusedOptionalDependencies, items);
    }

    fn add_unused_enum_members(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedEnumMemberFinding],
    ) {
        self.add_items(AuditCollection::UnusedEnumMembers, items);
    }

    fn add_unused_class_members(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedClassMemberFinding],
    ) {
        self.add_items(AuditCollection::UnusedClassMembers, items);
    }

    fn add_unused_store_members(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedStoreMemberFinding],
    ) {
        self.add_items(AuditCollection::UnusedStoreMembers, items);
    }

    fn add_unresolved_imports(
        &mut self,
        items: &[fallow_types::output_dead_code::UnresolvedImportFinding],
    ) {
        self.add_items(AuditCollection::UnresolvedImports, items);
    }

    fn add_unlisted_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::UnlistedDependencyFinding],
    ) {
        self.add_items(AuditCollection::UnlistedDependencies, items);
    }

    fn add_duplicate_exports(
        &mut self,
        items: &[fallow_types::output_dead_code::DuplicateExportFinding],
    ) {
        self.add_items(AuditCollection::DuplicateExports, items);
    }

    fn add_type_only_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::TypeOnlyDependencyFinding],
    ) {
        self.add_items(AuditCollection::TypeOnlyDependencies, items);
    }

    fn add_test_only_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::TestOnlyDependencyFinding],
    ) {
        self.add_items(AuditCollection::TestOnlyDependencies, items);
    }

    fn add_dev_dependencies_in_production(
        &mut self,
        items: &[fallow_types::output_dead_code::DevDependencyInProductionFinding],
    ) {
        self.add_items(AuditCollection::DevDependenciesInProduction, items);
    }

    fn add_circular_dependencies(
        &mut self,
        items: &[fallow_types::output_dead_code::CircularDependencyFinding],
    ) {
        self.add_items(AuditCollection::CircularDependencies, items);
    }

    fn add_re_export_cycles(
        &mut self,
        items: &[fallow_types::output_dead_code::ReExportCycleFinding],
    ) {
        self.add_items(AuditCollection::ReExportCycles, items);
    }

    fn add_package_cycles(
        &mut self,
        items: &[fallow_types::output_dead_code::PackageCycleFinding],
    ) {
        self.add_items(AuditCollection::PackageCycles, items);
    }

    fn add_boundary_violations(
        &mut self,
        items: &[fallow_types::output_dead_code::BoundaryViolationFinding],
    ) {
        self.add_items(AuditCollection::BoundaryViolations, items);
    }

    fn add_boundary_coverage_violations(
        &mut self,
        items: &[fallow_types::output_dead_code::BoundaryCoverageViolationFinding],
    ) {
        self.add_items(AuditCollection::BoundaryCoverageViolations, items);
    }

    fn add_boundary_call_violations(
        &mut self,
        items: &[fallow_types::output_dead_code::BoundaryCallViolationFinding],
    ) {
        self.add_items(AuditCollection::BoundaryCallViolations, items);
    }

    fn add_policy_violations(
        &mut self,
        items: &[fallow_types::output_dead_code::PolicyViolationFinding],
    ) {
        self.add_items(AuditCollection::PolicyViolations, items);
    }

    fn add_stale_suppressions(&mut self, items: &[fallow_types::results::StaleSuppression]) {
        self.add_items(AuditCollection::StaleSuppressions, items);
    }

    fn add_unresolved_catalog_references(
        &mut self,
        items: &[fallow_types::output_dead_code::UnresolvedCatalogReferenceFinding],
    ) {
        self.add_items(AuditCollection::UnresolvedCatalogReferences, items);
    }

    fn add_unused_catalog_entries(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedCatalogEntryFinding],
    ) {
        self.add_items(AuditCollection::UnusedCatalogEntries, items);
    }

    fn add_empty_catalog_groups(
        &mut self,
        items: &[fallow_types::output_dead_code::EmptyCatalogGroupFinding],
    ) {
        self.add_items(AuditCollection::EmptyCatalogGroups, items);
    }

    fn add_unused_dependency_overrides(
        &mut self,
        items: &[fallow_types::output_dead_code::UnusedDependencyOverrideFinding],
    ) {
        self.add_items(AuditCollection::UnusedDependencyOverrides, items);
    }

    fn add_misconfigured_dependency_overrides(
        &mut self,
        items: &[fallow_types::output_dead_code::MisconfiguredDependencyOverrideFinding],
    ) {
        self.add_items(AuditCollection::MisconfiguredDependencyOverrides, items);
    }
}

/// Retain only findings whose audit key was NOT present in `base` (i.e. was
/// introduced on the current branch).
///
/// When `base` is `None` (no baseline), all findings are kept.
///
/// This destructure is deliberately exhaustive: adding a field to
/// `AnalysisResults` must fail compilation here so the author decides
/// explicitly whether the new finding type needs an introduced-retain (add a
/// retain block) or has no key representation today (bind with underscore and
/// document why).
///
/// Sibling exhaustive sites: `fallow_engine::changed_files::filter_results_by_changed_files`,
/// `dead_code_keys`, `retain_introduced_dead_code`.
/// Non-exhaustive siblings the compiler will NOT flag (wire manually when a
/// finding type is added): `annotate_dead_code_json` (same key formats, this
/// file) and the per-collection `off` filter branches in
/// `crates/engine/src/dead_code.rs` (`apply_rule_severities`). The severity of
/// each record comes from the `RuleSeverity` table in
/// `crates/engine/src/effective_severity.rs`, whose visitors are exhaustive.
/// TypeScript mirror: `editors/vscode/scripts/codegen-contracts.mjs` derives
/// backwards-compatible aliases from `fallow schema` `ts_alias` rows.
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashSet across audit attribution keys"
)]
pub fn retain_introduced_dead_code(
    results: &mut fallow_types::results::AnalysisResults,
    root: &Path,
    base: Option<&FxHashSet<String>>,
) {
    let Some(base) = base else {
        return;
    };

    // Compute the introduced set before taking any mutable borrows. Note the
    // order differs from the pre-destructure code, which narrowed
    // unused_files/exports/types first and computed keys from the narrowed
    // results. Computing from the un-narrowed results is equivalent: those
    // retains keep exactly the items whose key is NOT in `base`, and the
    // `!base.contains(key)` filter below removes the same base-member keys
    // from the full key set, so `introduced` is identical either way.
    classify_introduced_dead_code_fields(results);
    macro_rules! retain {
        ($($field:ident),* $(,)?) => {
            $(retain_introduced(&mut results.$field, root, base);)*
        };
    }
    retain!(
        prop_drilling_chains,
        unused_files,
        unused_exports,
        unused_types,
        private_type_leaks,
        deprecated_exports_in_use,
        unused_enum_members,
        unused_class_members,
        unused_store_members,
        unresolved_imports,
        unused_dependencies,
        unused_dev_dependencies,
        unused_optional_dependencies,
        unlisted_dependencies,
        duplicate_exports,
        type_only_dependencies,
        test_only_dependencies,
        circular_dependencies,
        re_export_cycles,
        package_cycles,
        boundary_violations,
        boundary_coverage_violations,
        boundary_call_violations,
        policy_violations,
        stale_suppressions,
        unresolved_catalog_references,
        unused_catalog_entries,
        empty_catalog_groups,
        unused_dependency_overrides,
        misconfigured_dependency_overrides,
        invalid_client_exports,
        mixed_client_server_barrels,
        misplaced_directives,
        unprovided_injects,
        unrendered_components,
        unused_component_props,
        absent_component_props,
        unused_component_emits,
        unused_component_inputs,
        unused_component_outputs,
        unused_svelte_events,
        unused_effect_layers,
        unused_tagged_errors,
        unproduced_catch_tags,
        unused_server_actions,
        unused_load_data_keys,
        route_collisions,
        dynamic_segment_name_conflicts,
    );
}

/// Keep the findings of one collection whose audit key is absent from `base`.
fn retain_introduced<T: IdentifiedFinding>(
    items: &mut Vec<T>,
    root: &Path,
    base: &FxHashSet<String>,
) {
    let mut keys = collection_keys(items, root).into_iter();
    items.retain(|_| keys.next().is_some_and(|key| !base.contains(&key)));
}

fn classify_introduced_dead_code_fields(results: &fallow_types::results::AnalysisResults) {
    let fallow_types::results::AnalysisResults {
        unused_files: _unused_files,
        unused_exports: _unused_exports,
        unused_types: _unused_types,
        private_type_leaks: _private_type_leaks,
        deprecated_exports_in_use: _deprecated_exports_in_use,
        unused_dependencies: _unused_dependencies,
        unused_dev_dependencies: _unused_dev_dependencies,
        unused_optional_dependencies: _unused_optional_dependencies,
        unused_enum_members: _unused_enum_members,
        unused_class_members: _unused_class_members,
        unused_store_members: _unused_store_members,
        unresolved_imports: _unresolved_imports,
        unlisted_dependencies: _unlisted_dependencies,
        duplicate_exports: _duplicate_exports,
        type_only_dependencies: _type_only_dependencies,
        test_only_dependencies: _test_only_dependencies,
        dev_dependencies_in_production: _dev_dependencies_in_production,
        circular_dependencies: _circular_dependencies,
        re_export_cycles: _re_export_cycles,
        package_cycles: _package_cycles,
        boundary_violations: _boundary_violations,
        boundary_coverage_violations: _boundary_coverage_violations,
        boundary_call_violations: _boundary_call_violations,
        policy_violations: _policy_violations,
        stale_suppressions: _stale_suppressions,
        unused_catalog_entries: _unused_catalog_entries,
        empty_catalog_groups: _empty_catalog_groups,
        unresolved_catalog_references: _unresolved_catalog_references,
        unused_dependency_overrides: _unused_dependency_overrides,
        misconfigured_dependency_overrides: _misconfigured_dependency_overrides,
        invalid_client_exports: _invalid_client_exports,
        mixed_client_server_barrels: _mixed_client_server_barrels,
        misplaced_directives: _misplaced_directives,
        unprovided_injects: _unprovided_injects,
        unrendered_components: _unrendered_components,
        unused_component_props: _unused_component_props,
        absent_component_props: _absent_component_props,
        unused_component_emits: _unused_component_emits,
        unused_component_inputs: _unused_component_inputs,
        unused_component_outputs: _unused_component_outputs,
        unused_svelte_events: _unused_svelte_events,
        unused_effect_layers: _unused_effect_layers,
        unused_tagged_errors: _unused_tagged_errors,
        unproduced_catch_tags: _unproduced_catch_tags,
        unused_server_actions: _unused_server_actions,
        unused_load_data_keys: _unused_load_data_keys,
        unused_load_data_keys_global_abstain: _unused_load_data_keys_global_abstain,
        route_collisions: _route_collisions,
        dynamic_segment_name_conflicts: _dynamic_segment_name_conflicts,
        // Non-finding fields: counts and metadata, not subject to base-keyed
        // filtering.
        cascade_hidden: _cascade_hidden,
        cascade: _cascade,
        suppression_count: _suppression_count,
        unused_component_props_exempted: _unused_component_props_exempted,
        active_suppressions: _active_suppressions,
        feature_flags: _feature_flags,
        // Security findings are emitted via `fallow security`, not the audit
        // dead-code gate; they have no key representation and are not filtered
        // here.
        security_findings: _security_findings,
        security_unresolved_edge_files: _security_unresolved_edge_files,
        security_unresolved_callee_sites: _security_unresolved_callee_sites,
        security_unresolved_callee_diagnostics: _security_unresolved_callee_diagnostics,
        // Prop chains use source identities and occurrence-aware audit filtering.
        prop_drilling_chains: _prop_drilling_chains,
        // Thin wrappers are a dormant health signal (rule defaults to `off`);
        // no dead-code key and not base-filtered here.
        thin_wrappers: _thin_wrappers,
        // Duplicate prop shapes are a dormant multi-file health signal (rule
        // defaults to `off`); no dead-code key and not base-filtered here.
        duplicate_prop_shapes: _duplicate_prop_shapes,
        // Export usages and entry-point summary are metadata, not issue
        // collections; no key needed.
        export_usages: _export_usages,
        entry_point_summary: _entry_point_summary,
        // Render fan-in is a whole-project descriptive metric, not an issue
        // collection; no key needed.
        render_fan_in: _render_fan_in,
        // Per-component React intel is a descriptive ambient-editor carrier, not
        // an issue collection; no key needed.
        react_component_intel: _react_component_intel,
        semantic_framework_contracts: _semantic_framework_contracts,
    } = results;
}

/// The `introduced` flag of each finding in one collection, in order.
fn introduced_flags<T: IdentifiedFinding>(
    items: &[T],
    root: &Path,
    base: &FxHashSet<String>,
) -> Vec<bool> {
    collection_keys(items, root)
        .iter()
        .map(|key| !base.contains(key))
        .collect()
}

fn issue_was_introduced(key: &str, base: &FxHashSet<String>) -> bool {
    !base.contains(key)
}

fn annotate_issue_array<I>(json: &mut serde_json::Value, key: &str, introduced: I)
where
    I: IntoIterator<Item = bool>,
{
    let Some(items) = json.get_mut(key).and_then(serde_json::Value::as_array_mut) else {
        return;
    };
    for (item, introduced) in items.iter_mut().zip(introduced) {
        if let serde_json::Value::Object(map) = item {
            map.insert("introduced".to_string(), serde_json::json!(introduced));
        }
    }
}

/// Insert `"introduced": bool` into every dead-code finding object in the
/// serialized JSON by re-deriving each key and testing membership against
/// the base snapshot. JSON arrays must be in the same order as the typed
/// `results` collections they were serialized from.
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashSet across audit attribution keys"
)]
pub fn annotate_dead_code_json(
    json: &mut serde_json::Value,
    results: &fallow_types::results::AnalysisResults,
    root: &Path,
    base: &FxHashSet<String>,
) {
    macro_rules! annotate {
        ($($field:ident),* $(,)?) => {
            $(annotate_issue_array(
                json,
                stringify!($field),
                introduced_flags(&results.$field, root, base),
            );)*
        };
    }
    annotate!(
        prop_drilling_chains,
        unused_files,
        unused_exports,
        unused_types,
        private_type_leaks,
        deprecated_exports_in_use,
        unused_dependencies,
        unused_dev_dependencies,
        unused_optional_dependencies,
        type_only_dependencies,
        test_only_dependencies,
        unlisted_dependencies,
        unused_enum_members,
        unused_class_members,
        unused_store_members,
        unresolved_imports,
        duplicate_exports,
        circular_dependencies,
        re_export_cycles,
        package_cycles,
        boundary_violations,
        boundary_coverage_violations,
        boundary_call_violations,
        policy_violations,
        stale_suppressions,
        unresolved_catalog_references,
        unused_catalog_entries,
        empty_catalog_groups,
        unused_dependency_overrides,
        misconfigured_dependency_overrides,
        invalid_client_exports,
        mixed_client_server_barrels,
        misplaced_directives,
        unprovided_injects,
        unrendered_components,
        unused_component_props,
        absent_component_props,
        unused_component_emits,
        unused_component_inputs,
        unused_component_outputs,
        unused_svelte_events,
        unused_effect_layers,
        unused_tagged_errors,
        unproduced_catch_tags,
        unused_server_actions,
        route_collisions,
        dynamic_segment_name_conflicts,
    );
}

/// Annotate the sole legacy dead-code collection without a typed
/// `introduced` field. Every wrapper-backed collection is annotated from the
/// persisted [`AuditComparison`] instead.
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashSet across audit attribution keys"
)]
pub fn annotate_stale_suppressions_json(
    json: &mut serde_json::Value,
    results: &fallow_types::results::AnalysisResults,
    root: &Path,
    base: &FxHashSet<String>,
) {
    annotate_issue_array(
        json,
        "stale_suppressions",
        introduced_flags(&results.stale_suppressions, root, base),
    );
}

/// Insert `"introduced": bool` into each `findings` and `styling_findings`
/// object in serialized health JSON, matching entries to the typed report by
/// array position.
///
/// A complexity finding keeps the typed `introduced` flag that the audit
/// comparison set, because that flag compares metric values. Only a finding
/// without the typed flag falls back to identity-key membership in `base`.
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashSet across audit attribution keys"
)]
pub fn annotate_health_json(
    json: &mut serde_json::Value,
    report: &fallow_output::HealthReport,
    root: &Path,
    base: &FxHashSet<String>,
) {
    if let Some(items) = json
        .get_mut("findings")
        .and_then(serde_json::Value::as_array_mut)
    {
        for (item, finding) in items.iter_mut().zip(&report.findings) {
            if let serde_json::Value::Object(map) = item {
                map.insert(
                    "introduced".to_string(),
                    serde_json::json!(finding.introduced.unwrap_or_else(|| {
                        issue_was_introduced(&health_finding_key(finding, root), base)
                    })),
                );
            }
        }
    }
    if let Some(items) = json
        .get_mut("styling_findings")
        .and_then(serde_json::Value::as_array_mut)
    {
        for (item, finding) in items.iter_mut().zip(&report.styling_findings) {
            if let serde_json::Value::Object(map) = item {
                map.insert(
                    "introduced".to_string(),
                    serde_json::json!(issue_was_introduced(
                        &styling_finding_key(finding, root),
                        base
                    )),
                );
            }
        }
    }
}

/// Insert `"introduced": bool` into each `clone_groups` object in serialized
/// duplication JSON, matching groups to the typed report by array position.
#[expect(
    clippy::implicit_hasher,
    reason = "fallow standardizes on FxHashSet across audit attribution keys"
)]
pub fn annotate_dupes_json(
    json: &mut serde_json::Value,
    report: &fallow_types::duplicates::DuplicationReport,
    root: &Path,
    base: &FxHashSet<String>,
) {
    let Some(items) = json
        .get_mut("clone_groups")
        .and_then(serde_json::Value::as_array_mut)
    else {
        return;
    };
    for (item, group) in items.iter_mut().zip(&report.clone_groups) {
        if let serde_json::Value::Object(map) = item {
            map.insert(
                "introduced".to_string(),
                serde_json::json!(issue_was_introduced(&dupe_group_key(group, root), base)),
            );
        }
    }
}

/// Attach precomputed introduced membership to an audit JSON array.
pub fn annotate_domain_json(
    json: &mut serde_json::Value,
    collection: &str,
    introduced: impl IntoIterator<Item = bool>,
) {
    annotate_issue_array(json, collection, introduced);
}

/// Attach a `demotion_reason` to demoted entries of an audit JSON array,
/// matching entries to demoted membership by array position. Non-demoted
/// entries are left untouched so output without demotions stays byte-identical
/// (issue #2220).
pub fn annotate_domain_demotions_json(
    json: &mut serde_json::Value,
    collection: &str,
    demoted: impl IntoIterator<Item = bool>,
    reason: crate::CloneDemotionReason,
) {
    let Some(items) = json
        .get_mut(collection)
        .and_then(serde_json::Value::as_array_mut)
    else {
        return;
    };
    for (item, demoted) in items.iter_mut().zip(demoted) {
        if demoted && let serde_json::Value::Object(map) = item {
            map.insert("demotion_reason".to_string(), serde_json::json!(reason));
        }
    }
}

/// Attribution key set for every complexity finding in a health report.
pub fn health_keys(report: &fallow_output::HealthReport, root: &Path) -> FxHashSet<String> {
    report
        .findings
        .iter()
        .map(|finding| health_finding_key(finding, root))
        .collect()
}

/// Identity key for one complexity finding: `complexity:<path>:<function>`.
///
/// Line numbers are excluded, so a finding survives unrelated edits above it.
/// The exceeded category is excluded, so a category change keeps the match.
/// The new-only gate compares the metric values of matched findings, see
/// [`classify_complexity_findings`].
pub fn health_finding_key(finding: &fallow_output::ComplexityViolation, root: &Path) -> String {
    format!(
        "complexity:{}:{}",
        relative_key_path(Path::new(&finding.path), root),
        finding.name,
    )
}

/// Attribution key set for every styling finding in a health report.
pub fn styling_keys(report: &fallow_output::HealthReport, root: &Path) -> FxHashSet<String> {
    report
        .styling_findings
        .iter()
        .map(|finding| styling_finding_key(finding, root))
        .collect()
}

/// Attribution key for one styling finding:
/// `styling:<code>:<sub kind>:<path>:<line>:<value>`.
pub fn styling_finding_key(finding: &fallow_output::StylingFinding, root: &Path) -> String {
    format!(
        "styling:{}:{}:{}:{}:{}",
        finding.code,
        finding.sub_kind,
        relative_key_path(Path::new(&finding.path), root),
        finding.line,
        finding.value
    )
}

/// Attribution key set for every clone group in a duplication report.
pub fn dupes_keys(
    report: &fallow_types::duplicates::DuplicationReport,
    root: &Path,
) -> FxHashSet<String> {
    report
        .clone_groups
        .iter()
        .map(|group| dupe_group_key(group, root))
        .collect()
}

/// Attribution key for one clone group:
/// `dupe:<sorted files joined by |>:<tokens>:<lines>:<fragment hash>`.
/// The fragment hash keeps distinct groups spanning the same files apart;
/// line positions are excluded so a group survives shifts within its files.
pub fn dupe_group_key(group: &fallow_types::duplicates::CloneGroup, root: &Path) -> String {
    let mut files: Vec<String> = group
        .instances
        .iter()
        .map(|instance| relative_key_path(&instance.file, root))
        .collect();
    files.sort();
    files.dedup();
    let mut hasher = DefaultHasher::new();
    for instance in &group.instances {
        instance.fragment.hash(&mut hasher);
    }
    format!(
        "dupe:{}:{}:{}:{:x}",
        files.join("|"),
        group.token_count,
        group.line_count,
        hasher.finish()
    )
}

/// Keys of clone groups whose every instance lies entirely outside the diff's
/// added lines: no instance range contains an added line, so the changeset did
/// not write the duplicated text, and the group only became reportable (under
/// a new attribution key) because the changeset removed code elsewhere;
/// deduplicating one region can create or re-shape a clone group across files
/// (issue #2164). New-only gating demotes these groups to inherited so a
/// clone-removal refactor is not failed by the duplication it did not write.
/// An instance whose path cannot be mapped into the diff's namespace is
/// treated as touched, so its group keeps gating.
pub fn preexisting_dupe_group_keys<'a>(
    groups: impl IntoIterator<Item = &'a fallow_types::duplicates::CloneGroup>,
    root: &Path,
    diff: &fallow_output::DiffIndex,
) -> FxHashSet<String> {
    let instance_touched = |instance: &fallow_types::duplicates::CloneInstance| -> bool {
        let Some(rel) = diff.key_for(&instance.file, root) else {
            return true;
        };
        let start = u64::try_from(instance.start_line).unwrap_or(u64::MAX);
        let end = u64::try_from(instance.end_line).unwrap_or(u64::MAX);
        diff.range_overlaps_added(&rel, start, end)
    };
    groups
        .into_iter()
        .filter(|group| !group.instances.iter().any(instance_touched))
        .map(|group| dupe_group_key(group, root))
        .collect()
}

#[cfg(test)]
mod tests {
    use std::path::{Path, PathBuf};

    use fallow_config::{FallowConfig, Severity};
    use fallow_types::duplicates::{CloneGroup, CloneInstance, DuplicationReport};
    use fallow_types::envelope::AuditIntroduced;
    use fallow_types::extract::MemberKind;
    use fallow_types::output_dead_code::*;
    use fallow_types::output_format::OutputFormat;
    use fallow_types::results::*;
    use rustc_hash::FxHashSet;
    use serde_json::json;

    use fallow_output::{
        ComplexityViolation, ExceededThreshold, FindingSeverity, HealthFinding, HealthReport,
    };

    use super::{
        AuditDomainLedger, annotate_dead_code_json, annotate_dupes_json, annotate_health_json,
        annotate_stale_suppressions_json, dead_code_audit_ledger, dead_code_keys, dupe_group_key,
        dupes_keys, health_finding_key, health_keys, relative_key_path, remap_keys_for_renames,
        retain_introduced_dead_code,
    };

    fn root() -> PathBuf {
        PathBuf::from("/repo")
    }

    #[test]
    fn prop_audit_matches_source_occurrences_and_keeps_warnings_out_of_counts() {
        let root = root();
        let mut chain = PropDrillingChainFinding::with_actions(PropDrillingChain {
            prop: "user".to_owned(),
            depth: 3,
            hops: vec![PropDrillHop {
                file: root.join("src/Page.tsx"),
                line: 4,
                component: "Page".to_owned(),
            }],
        });
        let original = AnalysisResults {
            prop_drilling_chains: vec![chain.clone()],
            ..Default::default()
        };
        let base = dead_code_keys(&original, &root);
        chain.chain.hops[0].line = 12;
        let mut repeated = AnalysisResults {
            prop_drilling_chains: vec![chain.clone(), chain],
            ..Default::default()
        };
        let config: FallowConfig =
            serde_json::from_value(json!({"rules": {"prop-drilling": "error"}}))
                .expect("prop policy");
        let config = config.resolve(root.clone(), OutputFormat::Json, 1, false, true, None);
        let ledger = dead_code_audit_ledger(&repeated, &root, &config, Some(&base));
        assert_eq!(
            (ledger.introduced_count(), ledger.inherited_count()),
            (1, 1)
        );
        assert!(ledger.has_introduced_errors());
        ledger.annotate_results(&mut repeated);
        assert_eq!(
            repeated.prop_drilling_chains[0].introduced,
            Some(AuditIntroduced(false))
        );
        assert_eq!(
            repeated.prop_drilling_chains[1].introduced,
            Some(AuditIntroduced(true))
        );
        retain_introduced_dead_code(&mut repeated, &root, Some(&base));
        assert_eq!(repeated.prop_drilling_chains.len(), 1);
        let mut config = config;
        config.rules.prop_drilling = Severity::Warn;
        let ledger = dead_code_audit_ledger(&original, &root, &config, Some(&FxHashSet::default()));
        assert_eq!((ledger.introduced_count(), ledger.visible_count()), (0, 0));
        assert!(!ledger.has_introduced_errors());
        assert!(ledger.records()[0].introduced);
        let mut ledger = ledger;
        ledger.demote_unattributable_introductions(&FxHashSet::default());
        assert_eq!(
            (
                ledger.introduced_count(),
                ledger.inherited_count(),
                ledger.visible_count()
            ),
            (0, 0, 0)
        );
    }

    fn export(path: &Path, name: &str) -> UnusedExportFinding {
        UnusedExportFinding::with_actions(UnusedExport {
            path: path.to_path_buf(),
            export_name: name.to_string(),
            is_type_only: false,
            line: 1,
            col: 0,
            span_start: 0,
            is_re_export: false,
            deprecated: false,
            deprecated_reason: None,
        })
    }

    fn unused_file(path: &Path) -> UnusedFileFinding {
        UnusedFileFinding::with_actions(UnusedFile {
            path: path.to_path_buf(),
        })
    }

    fn dependency(path: &Path, package_name: &str) -> UnusedDependencyFinding {
        UnusedDependencyFinding::with_actions(UnusedDependency {
            package_name: package_name.to_string(),
            location: DependencyLocation::Dependencies,
            path: path.to_path_buf(),
            line: 4,
            used_in_workspaces: Vec::new(),
            declared_and_imported_in: Vec::new(),
        })
    }

    fn unresolved(path: &Path, specifier: &str) -> UnresolvedImportFinding {
        UnresolvedImportFinding::with_actions(UnresolvedImport {
            path: path.to_path_buf(),
            specifier: specifier.to_string(),
            line: 2,
            col: 1,
            specifier_col: 8,
        })
    }

    fn unlisted(path: &Path, package_name: &str) -> UnlistedDependencyFinding {
        UnlistedDependencyFinding::with_actions(UnlistedDependency {
            package_name: package_name.to_string(),
            imported_from: vec![
                ImportSite {
                    path: path.to_path_buf(),
                    line: 9,
                    col: 2,
                },
                ImportSite {
                    path: path.to_path_buf(),
                    line: 9,
                    col: 2,
                },
            ],
        })
    }

    fn duplicate_export(root: &Path) -> DuplicateExportFinding {
        DuplicateExportFinding::with_actions(DuplicateExport {
            export_name: "Button".to_string(),
            locations: vec![
                DuplicateLocation {
                    path: root.join("src/b.ts"),
                    line: 1,
                    col: 0,
                },
                DuplicateLocation {
                    path: root.join("src/a.ts"),
                    line: 1,
                    col: 0,
                },
                DuplicateLocation {
                    path: root.join("src/a.ts"),
                    line: 2,
                    col: 0,
                },
            ],
        })
    }

    fn deprecated_export(
        path: &Path,
        name: &str,
    ) -> fallow_types::output_dead_code::DeprecatedExportInUseFinding {
        fallow_types::output_dead_code::DeprecatedExportInUseFinding::with_actions(
            fallow_types::results::DeprecatedExportInUse {
                path: path.to_path_buf(),
                export_name: name.to_string(),
                is_type_only: false,
                line: 9,
                col: 13,
                span_start: 90,
                deprecated_reason: None,
                consumer_count: 1,
                consumers: Vec::new(),
                public_api: false,
            },
        )
    }

    fn sample_results(root: &Path) -> AnalysisResults {
        let source = root.join("src/page.ts");
        let package_json = root.join("package.json");
        let mut results = AnalysisResults::default();
        results
            .unused_files
            .push(unused_file(&root.join("src/dead.ts")));
        results.unused_exports.push(export(&source, "loader"));
        results
            .unused_dependencies
            .push(dependency(&package_json, "left-pad"));
        results
            .unresolved_imports
            .push(unresolved(&source, "./missing"));
        results.unlisted_dependencies.push(unlisted(&source, "zod"));
        results
            .deprecated_exports_in_use
            .push(deprecated_export(&source, "legacyLoader"));
        results.duplicate_exports.push(duplicate_export(root));
        results
    }

    #[test]
    fn relative_key_path_strips_root_and_normalizes_separators() {
        let path = Path::new("/repo/src\\feature\\index.ts");
        assert_eq!(
            relative_key_path(path, Path::new("/repo")),
            "src/feature/index.ts"
        );
    }

    #[test]
    fn dead_code_keys_are_stable_for_unsorted_and_duplicate_locations() {
        let root = root();
        let keys = dead_code_keys(&sample_results(&root), &root);

        assert!(keys.contains("unused-file:src/dead.ts"));
        assert!(keys.contains("unused-export:src/page.ts:loader"));
        assert!(keys.contains("unused-dependency:package.json:left-pad"));
        assert!(keys.contains("unresolved-import:src/page.ts:./missing"));
        assert!(keys.contains("unlisted-dependency:zod"));
        assert!(keys.contains("duplicate-export:Button:src/a.ts|src/b.ts"));
    }

    fn type_member_and_dependency_results(root: &Path) -> AnalysisResults {
        let source = root.join("src/types.ts");
        let package_json = root.join("package.json");
        let mut results = AnalysisResults::default();
        results
            .unused_types
            .push(UnusedTypeFinding::with_actions(UnusedExport {
                path: source.clone(),
                export_name: "UnusedType".to_string(),
                is_type_only: true,
                line: 3,
                col: 0,
                span_start: 12,
                is_re_export: false,
                deprecated: false,
                deprecated_reason: None,
            }));
        results
            .private_type_leaks
            .push(PrivateTypeLeakFinding::with_actions(PrivateTypeLeak {
                path: source.clone(),
                export_name: "makePublic".to_string(),
                type_name: "PrivateShape".to_string(),
                line: 7,
                col: 12,
                span_start: 64,
                semantic: None,
            }));
        results
            .unused_dev_dependencies
            .push(UnusedDevDependencyFinding::with_actions(UnusedDependency {
                package_name: "vite".to_string(),
                location: DependencyLocation::DevDependencies,
                path: package_json.clone(),
                line: 10,
                used_in_workspaces: Vec::new(),
                declared_and_imported_in: Vec::new(),
            }));
        results
            .unused_optional_dependencies
            .push(UnusedOptionalDependencyFinding::with_actions(
                UnusedDependency {
                    package_name: "fsevents".to_string(),
                    location: DependencyLocation::OptionalDependencies,
                    path: package_json.clone(),
                    line: 11,
                    used_in_workspaces: Vec::new(),
                    declared_and_imported_in: Vec::new(),
                },
            ));
        results
            .unused_enum_members
            .push(UnusedEnumMemberFinding::with_actions(UnusedMember {
                path: source.clone(),
                parent_name: "Status".to_string(),
                member_name: "Idle".to_string(),
                kind: MemberKind::EnumMember,
                line: 15,
                col: 2,
            }));
        results
            .unused_class_members
            .push(UnusedClassMemberFinding::with_actions(UnusedMember {
                path: source,
                parent_name: "Controller".to_string(),
                member_name: "legacy".to_string(),
                kind: MemberKind::ClassMethod,
                line: 21,
                col: 2,
            }));
        results
            .type_only_dependencies
            .push(TypeOnlyDependencyFinding::with_actions(
                TypeOnlyDependency {
                    package_name: "zod".to_string(),
                    path: package_json.clone(),
                    line: 12,
                },
            ));
        results
            .test_only_dependencies
            .push(TestOnlyDependencyFinding::with_actions(
                TestOnlyDependency {
                    package_name: "vitest".to_string(),
                    path: package_json,
                    line: 13,
                },
            ));

        results
    }

    #[test]
    fn dead_code_keys_cover_type_member_and_dependency_variants() {
        let root = root();
        let results = type_member_and_dependency_results(&root);

        let keys = dead_code_keys(&results, &root);

        assert!(keys.contains("unused-type:src/types.ts:UnusedType"));
        assert!(keys.contains("private-type-leak:src/types.ts:makePublic:PrivateShape"));
        assert!(keys.contains("unused-dev-dependency:package.json:vite"));
        assert!(keys.contains("unused-optional-dependency:package.json:fsevents"));
        assert!(keys.contains("unused-enum-member:src/types.ts:Status:Idle"));
        assert!(keys.contains("unused-class-member:src/types.ts:Controller:legacy"));
        assert!(keys.contains("type-only-dependency:package.json:zod"));
        assert!(keys.contains("test-only-dependency:package.json:vitest"));
    }

    #[expect(
        clippy::too_many_lines,
        reason = "test fixture; linear setup/assert, length is not a maintainability concern"
    )]
    fn graph_boundary_catalog_override_results(root: &std::path::Path) -> AnalysisResults {
        let source = root.join("src/app.ts");
        let other = root.join("src/other.ts");
        let workspace = root.join("pnpm-workspace.yaml");
        let mut results = AnalysisResults::default();
        results
            .circular_dependencies
            .push(CircularDependencyFinding::with_actions(
                CircularDependency {
                    files: vec![other.clone(), source.clone()],
                    length: 2,
                    line: 4,
                    col: 0,
                    edges: Vec::new(),
                    is_cross_package: false,
                },
            ));
        results
            .re_export_cycles
            .push(ReExportCycleFinding::with_actions(ReExportCycle {
                files: vec![source.clone()],
                kind: ReExportCycleKind::SelfLoop,
            }));
        results.package_cycles.push(
            fallow_types::output_dead_code::PackageCycleFinding::with_actions(
                fallow_types::results::PackageCycle {
                    packages: vec!["@x/a".to_string(), "@x/b".to_string()],
                    package_roots: Vec::new(),
                    length: 2,
                    edges: vec![fallow_types::results::PackageCycleEdge {
                        from_package: "@x/a".to_string(),
                        to_package: "@x/b".to_string(),
                        path: source.clone(),
                        target_path: other.clone(),
                        line: 4,
                        col: 0,
                        type_only: false,
                    }],
                    group_truncated: false,
                },
            ),
        );
        results
            .boundary_violations
            .push(BoundaryViolationFinding::with_actions(BoundaryViolation {
                from_path: source.clone(),
                to_path: other,
                from_zone: "ui".to_string(),
                to_zone: "server".to_string(),
                import_specifier: "../other".to_string(),
                line: 1,
                col: 0,
                via_path: None,
            }));
        results
            .boundary_coverage_violations
            .push(BoundaryCoverageViolationFinding::with_actions(
                BoundaryCoverageViolation {
                    path: root.join("src/unmatched.ts"),
                    line: 1,
                    col: 0,
                },
            ));
        results
            .boundary_call_violations
            .push(BoundaryCallViolationFinding::with_actions(
                BoundaryCallViolation {
                    path: source.clone(),
                    line: 12,
                    col: 4,
                    zone: "ui".to_string(),
                    callee: "child_process.exec".to_string(),
                    pattern: "child_process.*".to_string(),
                },
            ));
        results.stale_suppressions.push(StaleSuppression {
            finding_id: None,
            path: source,
            line: 2,
            col: 0,
            origin: SuppressionOrigin::Comment {
                issue_kind: Some("unused-export".to_string()),
                reason: None,
                is_file_level: false,
                kind_known: true,
            },
            missing_reason: false,
            actions: StaleSuppression::actions_for(false),
            effective_severity: None,
        });
        results.stale_suppressions.push(StaleSuppression {
            finding_id: None,
            path: root.join("src/app.ts"),
            line: 2,
            col: 0,
            origin: SuppressionOrigin::Comment {
                issue_kind: Some("unused-export".to_string()),
                reason: None,
                is_file_level: false,
                kind_known: true,
            },
            missing_reason: true,
            actions: StaleSuppression::actions_for(true),
            effective_severity: None,
        });
        results.unresolved_catalog_references.push(
            UnresolvedCatalogReferenceFinding::with_actions(UnresolvedCatalogReference {
                entry_name: "react".to_string(),
                catalog_name: "default".to_string(),
                path: root.join("packages/app/package.json"),
                line: 9,
                available_in_catalogs: vec!["react18".to_string()],
            }),
        );
        results
            .unused_catalog_entries
            .push(UnusedCatalogEntryFinding::with_actions(
                UnusedCatalogEntry {
                    entry_name: "lodash".to_string(),
                    catalog_name: "default".to_string(),
                    path: workspace.clone(),
                    line: 3,
                    hardcoded_consumers: Vec::new(),
                },
            ));
        results
            .empty_catalog_groups
            .push(EmptyCatalogGroupFinding::with_actions(EmptyCatalogGroup {
                catalog_name: "react17".to_string(),
                path: workspace.clone(),
                line: 7,
            }));
        results
            .unused_dependency_overrides
            .push(UnusedDependencyOverrideFinding::with_actions(
                UnusedDependencyOverride {
                    raw_key: "left-pad".to_string(),
                    target_package: "left-pad".to_string(),
                    parent_package: None,
                    version_constraint: None,
                    version_range: "^1.3.0".to_string(),
                    source: DependencyOverrideSource::PnpmWorkspaceYaml,
                    path: workspace.clone(),
                    line: 11,
                    hint: None,
                },
            ));
        results.misconfigured_dependency_overrides.push(
            MisconfiguredDependencyOverrideFinding::with_actions(MisconfiguredDependencyOverride {
                raw_key: ">".to_string(),
                target_package: None,
                raw_value: String::new(),
                reason: DependencyOverrideMisconfigReason::UnparsableKey,
                source: DependencyOverrideSource::PnpmWorkspaceYaml,
                path: workspace,
                line: 12,
            }),
        );
        results
    }

    #[test]
    fn dead_code_keys_cover_graph_boundary_catalog_and_override_variants() {
        let root = root();
        let results = graph_boundary_catalog_override_results(&root);

        let keys = dead_code_keys(&results, &root);

        assert!(keys.contains("circular-dependency:src/app.ts|src/other.ts"));
        assert!(keys.contains("re-export-cycle:self-loop:src/app.ts"));
        assert!(keys.contains("boundary-violation:src/app.ts:src/other.ts"));
        assert!(keys.contains("boundary-coverage:src/unmatched.ts"));
        assert!(keys.contains("boundary-call-violation:src/app.ts:child_process.exec"));
        assert!(keys.contains("stale-suppression:src/app.ts:comment:unused-export:line"));
        assert!(keys.contains("missing-suppression-reason:src/app.ts:comment:unused-export:line"));
        assert!(
            keys.contains("unresolved-catalog-reference:packages/app/package.json:default:react")
        );
        assert!(keys.contains("unused-catalog-entry:pnpm-workspace.yaml:default:lodash"));
        assert!(keys.contains("empty-catalog-group:pnpm-workspace.yaml:react17"));
        assert!(keys.contains("unused-dependency-override:pnpm-workspace.yaml:left-pad"));
        assert!(keys.contains("misconfigured-dependency-override:pnpm-workspace.yaml:>"));
    }

    #[test]
    fn retain_introduced_dead_code_keeps_only_findings_absent_from_base() {
        let root = root();
        let mut results = sample_results(&root);
        let base = FxHashSet::from_iter([
            "unused-file:src/dead.ts".to_string(),
            "unused-dependency:package.json:left-pad".to_string(),
            "unresolved-import:src/page.ts:./missing".to_string(),
        ]);

        retain_introduced_dead_code(&mut results, &root, Some(&base));

        assert!(results.unused_files.is_empty());
        assert!(results.unused_dependencies.is_empty());
        assert!(results.unresolved_imports.is_empty());
        assert_eq!(results.unused_exports.len(), 1);
        assert_eq!(results.unlisted_dependencies.len(), 1);
        assert_eq!(results.duplicate_exports.len(), 1);
    }

    #[test]
    fn annotate_dead_code_json_marks_introduced_status_by_matching_key_order() {
        let root = root();
        let results = sample_results(&root);
        let base = FxHashSet::from_iter([
            "unused-file:src/dead.ts".to_string(),
            "unlisted-dependency:zod".to_string(),
        ]);
        let mut json = json!({
            "unused_files": [{}],
            "unused_exports": [{}],
            "unused_dependencies": [{}],
            "unresolved_imports": [{}],
            "unlisted_dependencies": [{}],
            "duplicate_exports": [{}],
        });

        annotate_dead_code_json(&mut json, &results, &root, &base);

        assert_eq!(json["unused_files"][0]["introduced"], false);
        assert_eq!(json["unused_exports"][0]["introduced"], true);
        assert_eq!(json["unused_dependencies"][0]["introduced"], true);
        assert_eq!(json["unresolved_imports"][0]["introduced"], true);
        assert_eq!(json["unlisted_dependencies"][0]["introduced"], false);
        assert_eq!(json["duplicate_exports"][0]["introduced"], true);
    }

    // --- key-building coverage for lines 68-177 (framework-specific key fns) ---

    fn effect_results(root: &Path) -> AnalysisResults {
        use fallow_types::output_dead_code::{
            UnproducedCatchTagFinding, UnusedEffectLayerFinding, UnusedTaggedErrorFinding,
        };
        use fallow_types::results::{
            EffectLayerKind, UnproducedCatchTag, UnusedEffectLayer, UnusedTaggedError,
        };
        AnalysisResults {
            unused_effect_layers: vec![UnusedEffectLayerFinding::with_actions(UnusedEffectLayer {
                path: root.join("src/services.ts"),
                name: "CacheLive".to_owned(),
                kind: EffectLayerKind::TopLevel,
                line: 3,
                col: 0,
                dead_consumers: vec!["OrphanLive".to_owned()],
            })],
            unused_tagged_errors: vec![UnusedTaggedErrorFinding::with_actions(UnusedTaggedError {
                path: root.join("src/errors.ts"),
                name: "Expired".to_owned(),
                tag: "Expired".to_owned(),
                line: 4,
                col: 0,
                catch_sites: Vec::new(),
            })],
            unproduced_catch_tags: vec![UnproducedCatchTagFinding::with_actions(
                UnproducedCatchTag {
                    path: root.join("src/main.ts"),
                    tag: "Expired".to_owned(),
                    line: 5,
                    col: 0,
                    candidate_classes: vec!["Expired".to_owned()],
                },
            )],
            ..Default::default()
        }
    }

    fn framework_inject_and_render_results(root: &Path) -> AnalysisResults {
        let src = root.join("src/App.vue");
        let mut results = AnalysisResults::default();
        results
            .unprovided_injects
            .push(UnprovidedInjectFinding::with_actions(UnprovidedInject {
                path: src.clone(),
                key_name: "userStore".to_string(),
                framework: "vue".to_string(),
                line: 5,
                col: 0,
            }));
        results
            .unrendered_components
            .push(UnrenderedComponentFinding::with_actions(
                UnrenderedComponent {
                    path: src.clone(),
                    component_name: "MyModal".to_string(),
                    framework: "vue".to_string(),
                    reachable_via: None,
                    line: 1,
                    col: 0,
                },
            ));
        results
            .unused_component_props
            .push(UnusedComponentPropFinding::with_actions(
                UnusedComponentProp {
                    path: src.clone(),
                    component_name: "MyModal".to_string(),
                    prop_name: "title".to_string(),
                    line: 3,
                    col: 2,
                },
            ));
        results
            .unused_component_emits
            .push(UnusedComponentEmitFinding::with_actions(
                UnusedComponentEmit {
                    path: src,
                    component_name: "MyModal".to_string(),
                    emit_name: "close".to_string(),
                    line: 4,
                    col: 2,
                },
            ));
        results
            .unused_svelte_events
            .push(UnusedSvelteEventFinding::with_actions(UnusedSvelteEvent {
                path: root.join("src/Counter.svelte"),
                component_name: "Counter".to_string(),
                event_name: "increment".to_string(),
                line: 8,
                col: 0,
            }));

        results
    }

    #[test]
    fn dead_code_keys_cover_framework_inject_and_render_variants() {
        let root = root();
        let results = framework_inject_and_render_results(&root);

        let keys = dead_code_keys(&results, &root);

        assert!(keys.contains("unprovided-inject:src/App.vue:userStore"));
        assert!(keys.contains("unrendered-component:src/App.vue:MyModal"));
        assert!(keys.contains("unused-component-prop:src/App.vue:MyModal:title"));
        assert!(keys.contains("unused-component-emit:src/App.vue:MyModal:close"));
        assert!(keys.contains("unused-svelte-event:src/Counter.svelte:Counter:increment"));
    }

    fn server_action_load_data_and_route_results(root: &Path) -> AnalysisResults {
        let actions_file = root.join("src/actions/submit.ts");
        let page_file = root.join("src/routes/blog/+page.server.ts");
        let route_file = root.join("app/(auth)/login/page.tsx");
        let route_file2 = root.join("app/login/page.tsx");
        let mut results = AnalysisResults::default();
        results
            .unused_server_actions
            .push(UnusedServerActionFinding::with_actions(
                UnusedServerAction {
                    path: actions_file,
                    action_name: "submitForm".to_string(),
                    line: 2,
                    col: 0,
                },
            ));
        results
            .unused_load_data_keys
            .push(UnusedLoadDataKeyFinding::with_actions(UnusedLoadDataKey {
                path: page_file,
                key_name: "posts".to_string(),
                line: 10,
                col: 4,
                route_dir: None,
            }));
        results
            .route_collisions
            .push(RouteCollisionFinding::with_actions(RouteCollision {
                path: route_file.clone(),
                url: "/login".to_string(),
                conflicting_paths: vec![route_file2.clone()],
                line: 1,
                col: 0,
            }));
        results.dynamic_segment_name_conflicts.push(
            DynamicSegmentNameConflictFinding::with_actions(DynamicSegmentNameConflict {
                path: route_file,
                position: "/shop".to_string(),
                conflicting_segments: vec!["[id]".to_string(), "[slug]".to_string()],
                conflicting_paths: vec![route_file2],
                line: 1,
                col: 0,
            }),
        );

        results
    }

    #[test]
    fn dead_code_keys_cover_server_action_load_data_and_route_variants() {
        let root = root();
        let results = server_action_load_data_and_route_results(&root);

        let keys = dead_code_keys(&results, &root);

        assert!(keys.contains("unused-server-action:src/actions/submit.ts:submitForm"));
        assert!(keys.contains("unused-load-data-key:src/routes/blog/+page.server.ts:posts"));
        assert!(keys.contains("route-collision:app/(auth)/login/page.tsx:/login"));
        assert!(keys.contains("dynamic-segment-name-conflict:app/(auth)/login/page.tsx:/shop"));
    }

    fn angular_input_output_and_policy_results(root: &Path) -> AnalysisResults {
        let component = root.join("src/app/card.component.ts");
        let src = root.join("src/utils.ts");
        let mut results = AnalysisResults::default();
        results
            .unused_component_inputs
            .push(UnusedComponentInputFinding::with_actions(
                UnusedComponentInput {
                    path: component.clone(),
                    component_name: "CardComponent".to_string(),
                    input_name: "label".to_string(),
                    line: 12,
                    col: 4,
                },
            ));
        results
            .unused_component_outputs
            .push(UnusedComponentOutputFinding::with_actions(
                UnusedComponentOutput {
                    path: component,
                    component_name: "CardComponent".to_string(),
                    output_name: "clicked".to_string(),
                    line: 13,
                    col: 4,
                },
            ));
        results
            .policy_violations
            .push(PolicyViolationFinding::with_actions(PolicyViolation {
                path: src,
                line: 7,
                col: 0,
                pack: "security".to_string(),
                rule_id: "no-eval".to_string(),
                kind: PolicyRuleKind::BannedCall,
                matched: "eval".to_string(),
                severity: PolicyViolationSeverity::Error,
                message: None,
            }));

        results
    }

    #[test]
    fn dead_code_keys_cover_angular_input_output_and_policy_variants() {
        let root = root();
        let results = angular_input_output_and_policy_results(&root);

        let keys = dead_code_keys(&results, &root);

        assert!(
            keys.contains("unused-component-input:src/app/card.component.ts:CardComponent:label")
        );
        assert!(
            keys.contains(
                "unused-component-output:src/app/card.component.ts:CardComponent:clicked"
            )
        );
        assert!(keys.contains("policy-violation:src/utils.ts:security:no-eval:eval"));
    }

    #[test]
    fn dead_code_keys_cover_re_export_cycle_multi_node_variant() {
        let root = root();
        let a = root.join("src/a.ts");
        let b = root.join("src/b.ts");
        let mut results = AnalysisResults::default();
        results
            .re_export_cycles
            .push(ReExportCycleFinding::with_actions(ReExportCycle {
                files: vec![b, a],
                kind: ReExportCycleKind::MultiNode,
            }));

        let keys = dead_code_keys(&results, &root);

        // multi-node variant hits line 275; files are sorted
        assert!(keys.contains("re-export-cycle:multi-node:src/a.ts|src/b.ts"));
    }

    #[test]
    fn dead_code_keys_cover_package_cycles_by_package_roots() {
        let root = root();
        let mut results = AnalysisResults::default();
        results.package_cycles.push(
            fallow_types::output_dead_code::PackageCycleFinding::with_actions(
                fallow_types::results::PackageCycle {
                    packages: vec!["@x/b".to_string(), "@x/a".to_string()],
                    package_roots: vec![root.join("packages/b"), root.join("packages/a")],
                    length: 2,
                    edges: vec![fallow_types::results::PackageCycleEdge {
                        from_package: "@x/a".to_string(),
                        to_package: "@x/b".to_string(),
                        path: root.join("packages/a/src/index.ts"),
                        target_path: root.join("packages/b/src/index.ts"),
                        line: 3,
                        col: 0,
                        type_only: false,
                    }],
                    group_truncated: false,
                },
            ),
        );

        let keys = dead_code_keys(&results, &root);

        assert!(
            keys.contains("package-cycle:packages/a|packages/b"),
            "{keys:?}"
        );
    }

    fn unused_store_member_results(root: &Path) -> AnalysisResults {
        let src = root.join("src/store.ts");
        let mut results = AnalysisResults::default();
        results
            .unused_store_members
            .push(UnusedStoreMemberFinding::with_actions(UnusedMember {
                path: src,
                parent_name: "useAuthStore".to_string(),
                member_name: "resetPassword".to_string(),
                kind: MemberKind::ClassMethod,
                line: 42,
                col: 2,
            }));

        results
    }

    #[test]
    fn dead_code_keys_cover_unused_store_member() {
        let root = root();
        let results = unused_store_member_results(&root);

        let keys = dead_code_keys(&results, &root);

        assert!(keys.contains("unused-store-member:src/store.ts:useAuthStore:resetPassword"));
    }

    // --- annotate_dead_code_json for framework / component / render / policy arrays ---

    #[test]
    fn annotate_dead_code_json_marks_framework_keys_correctly() {
        let root = root();
        let src = root.join("src/App.vue");
        let mut results = AnalysisResults::default();
        results
            .unprovided_injects
            .push(UnprovidedInjectFinding::with_actions(UnprovidedInject {
                path: src.clone(),
                key_name: "theme".to_string(),
                framework: "vue".to_string(),
                line: 3,
                col: 0,
            }));
        results
            .unrendered_components
            .push(UnrenderedComponentFinding::with_actions(
                UnrenderedComponent {
                    path: src.clone(),
                    component_name: "Dialog".to_string(),
                    framework: "vue".to_string(),
                    reachable_via: None,
                    line: 1,
                    col: 0,
                },
            ));
        results
            .unused_component_props
            .push(UnusedComponentPropFinding::with_actions(
                UnusedComponentProp {
                    path: src.clone(),
                    component_name: "Dialog".to_string(),
                    prop_name: "open".to_string(),
                    line: 5,
                    col: 2,
                },
            ));
        results
            .unused_component_emits
            .push(UnusedComponentEmitFinding::with_actions(
                UnusedComponentEmit {
                    path: src,
                    component_name: "Dialog".to_string(),
                    emit_name: "dismiss".to_string(),
                    line: 6,
                    col: 2,
                },
            ));

        // Only the inject is in the base; the rest are new.
        let base = FxHashSet::from_iter(["unprovided-inject:src/App.vue:theme".to_string()]);
        let mut json_val = json!({
            "unprovided_injects": [{}],
            "unrendered_components": [{}],
            "unused_component_props": [{}],
            "unused_component_emits": [{}],
        });

        annotate_dead_code_json(&mut json_val, &results, &root, &base);

        assert_eq!(json_val["unprovided_injects"][0]["introduced"], false);
        assert_eq!(json_val["unrendered_components"][0]["introduced"], true);
        assert_eq!(json_val["unused_component_props"][0]["introduced"], true);
        assert_eq!(json_val["unused_component_emits"][0]["introduced"], true);
    }

    #[test]
    fn annotate_dead_code_json_marks_component_io_and_route_keys_correctly() {
        let root = root();
        let component = root.join("src/card.component.ts");
        let svelte_file = root.join("src/Counter.svelte");
        let page_file = root.join("src/routes/+page.server.ts");
        let route_file = root.join("app/about/page.tsx");
        let route_file2 = root.join("app/(info)/about/page.tsx");
        let mut results = AnalysisResults::default();
        results
            .unused_component_inputs
            .push(UnusedComponentInputFinding::with_actions(
                UnusedComponentInput {
                    path: component.clone(),
                    component_name: "CardComponent".to_string(),
                    input_name: "size".to_string(),
                    line: 8,
                    col: 2,
                },
            ));
        results
            .unused_component_outputs
            .push(UnusedComponentOutputFinding::with_actions(
                UnusedComponentOutput {
                    path: component,
                    component_name: "CardComponent".to_string(),
                    output_name: "hovered".to_string(),
                    line: 9,
                    col: 2,
                },
            ));
        results
            .unused_svelte_events
            .push(UnusedSvelteEventFinding::with_actions(UnusedSvelteEvent {
                path: svelte_file,
                component_name: "Counter".to_string(),
                event_name: "reset".to_string(),
                line: 12,
                col: 0,
            }));
        results
            .unused_server_actions
            .push(UnusedServerActionFinding::with_actions(
                UnusedServerAction {
                    path: page_file,
                    action_name: "deletePost".to_string(),
                    line: 3,
                    col: 0,
                },
            ));
        results
            .route_collisions
            .push(RouteCollisionFinding::with_actions(RouteCollision {
                path: route_file.clone(),
                url: "/about".to_string(),
                conflicting_paths: vec![route_file2.clone()],
                line: 1,
                col: 0,
            }));
        results.dynamic_segment_name_conflicts.push(
            DynamicSegmentNameConflictFinding::with_actions(DynamicSegmentNameConflict {
                path: route_file,
                position: "/".to_string(),
                conflicting_segments: vec!["[id]".to_string()],
                conflicting_paths: vec![route_file2],
                line: 1,
                col: 0,
            }),
        );

        // Nothing is in base: all are introduced.
        let base = FxHashSet::default();
        let mut json_val = json!({
            "unused_component_inputs": [{}],
            "unused_component_outputs": [{}],
            "unused_svelte_events": [{}],
            "unused_server_actions": [{}],
            "route_collisions": [{}],
            "dynamic_segment_name_conflicts": [{}],
        });

        annotate_dead_code_json(&mut json_val, &results, &root, &base);

        assert_eq!(json_val["unused_component_inputs"][0]["introduced"], true);
        assert_eq!(json_val["unused_component_outputs"][0]["introduced"], true);
        assert_eq!(json_val["unused_svelte_events"][0]["introduced"], true);
        assert_eq!(json_val["unused_server_actions"][0]["introduced"], true);
        assert_eq!(json_val["route_collisions"][0]["introduced"], true);
        assert_eq!(
            json_val["dynamic_segment_name_conflicts"][0]["introduced"],
            true
        );
    }

    #[test]
    fn annotate_dead_code_json_marks_members_and_dependencies_correctly() {
        let root = root();
        let src = root.join("src/types.ts");
        let pkg = root.join("package.json");
        let mut results = AnalysisResults::default();
        results
            .unused_enum_members
            .push(UnusedEnumMemberFinding::with_actions(UnusedMember {
                path: src.clone(),
                parent_name: "Color".to_string(),
                member_name: "Blue".to_string(),
                kind: MemberKind::EnumMember,
                line: 5,
                col: 2,
            }));
        results
            .unused_class_members
            .push(UnusedClassMemberFinding::with_actions(UnusedMember {
                path: src.clone(),
                parent_name: "Service".to_string(),
                member_name: "reset".to_string(),
                kind: MemberKind::ClassMethod,
                line: 20,
                col: 2,
            }));
        results
            .unused_store_members
            .push(UnusedStoreMemberFinding::with_actions(UnusedMember {
                path: src,
                parent_name: "useStore".to_string(),
                member_name: "logout".to_string(),
                kind: MemberKind::ClassMethod,
                line: 30,
                col: 2,
            }));
        results
            .unused_dev_dependencies
            .push(UnusedDevDependencyFinding::with_actions(UnusedDependency {
                package_name: "typescript".to_string(),
                location: DependencyLocation::DevDependencies,
                path: pkg.clone(),
                line: 8,
                used_in_workspaces: Vec::new(),
                declared_and_imported_in: Vec::new(),
            }));
        results
            .type_only_dependencies
            .push(TypeOnlyDependencyFinding::with_actions(
                TypeOnlyDependency {
                    package_name: "zod".to_string(),
                    path: pkg.clone(),
                    line: 9,
                },
            ));
        results
            .test_only_dependencies
            .push(TestOnlyDependencyFinding::with_actions(
                TestOnlyDependency {
                    package_name: "vitest".to_string(),
                    path: pkg,
                    line: 10,
                },
            ));

        // Enum member and dev-dep are in base; class member, store member, type-only
        // dep, and test-only dep are new.
        let base = FxHashSet::from_iter([
            "unused-enum-member:src/types.ts:Color:Blue".to_string(),
            "unused-dev-dependency:package.json:typescript".to_string(),
        ]);
        let mut json_val = json!({
            "unused_enum_members": [{}],
            "unused_class_members": [{}],
            "unused_store_members": [{}],
            "unused_dev_dependencies": [{}],
            "type_only_dependencies": [{}],
            "test_only_dependencies": [{}],
        });

        annotate_dead_code_json(&mut json_val, &results, &root, &base);

        assert_eq!(json_val["unused_enum_members"][0]["introduced"], false);
        assert_eq!(json_val["unused_class_members"][0]["introduced"], true);
        assert_eq!(json_val["unused_store_members"][0]["introduced"], true);
        assert_eq!(json_val["unused_dev_dependencies"][0]["introduced"], false);
        assert_eq!(json_val["type_only_dependencies"][0]["introduced"], true);
        assert_eq!(json_val["test_only_dependencies"][0]["introduced"], true);
    }

    #[test]
    fn annotate_dead_code_json_is_noop_when_issue_keys_absent() {
        let root = root();
        let results = sample_results(&root);
        let base = FxHashSet::default();
        let mut json_val = json!({"other_key": []});
        let original = json_val.clone();

        annotate_dead_code_json(&mut json_val, &results, &root, &base);

        assert_eq!(json_val, original);
    }

    // --- annotate_health_json ---

    fn make_violation(path: &Path, name: &str) -> ComplexityViolation {
        ComplexityViolation {
            path: path.to_path_buf(),
            name: name.to_string(),
            line: 1,
            col: 0,
            cyclomatic: 20,
            cognitive: 5,
            line_count: 30,
            param_count: 2,
            react_hook_count: 0,
            react_jsx_max_depth: 0,
            react_prop_count: 0,
            react_hook_profile: None,
            exceeded: ExceededThreshold::Cyclomatic,
            effective_severity: None,
            severity: FindingSeverity::High,
            crap: None,
            mutation: None,
            coverage_pct: None,
            coverage_tier: None,
            coverage_source: None,
            inherited_from: None,
            component_rollup: None,
            contributions: Vec::new(),
            effective_thresholds: None,
            threshold_source: None,
        }
    }

    fn make_health_report(paths_and_names: &[(&Path, &str)]) -> HealthReport {
        let findings = paths_and_names
            .iter()
            .map(|(path, name)| HealthFinding::from(make_violation(path, name)))
            .collect();
        HealthReport {
            findings,
            ..HealthReport::default()
        }
    }

    #[test]
    fn health_keys_produces_stable_key_per_finding() {
        let root = root();
        let path = root.join("src/heavy.ts");
        let report = make_health_report(&[(&path, "processAll")]);
        let keys = health_keys(&report, &root);
        assert!(keys.contains("complexity:src/heavy.ts:processAll"));
    }

    #[test]
    fn health_finding_key_uses_path_and_name() {
        let root = root();
        let path = root.join("src/heavy.ts");
        let violation = make_violation(&path, "render");
        let key = health_finding_key(&violation, &root);
        assert_eq!(key, "complexity:src/heavy.ts:render");
    }

    #[test]
    fn annotate_health_json_marks_introduced_and_inherited_flags() {
        let root = root();
        let path_a = root.join("src/heavy.ts");
        let path_b = root.join("src/other.ts");
        let report = make_health_report(&[(&path_a, "doWork"), (&path_b, "render")]);

        // Only path_b:render is in the base.
        let base = FxHashSet::from_iter(["complexity:src/other.ts:render".to_string()]);
        let mut json_val = json!({
            "findings": [{}, {}],
        });

        annotate_health_json(&mut json_val, &report, &root, &base);

        assert_eq!(json_val["findings"][0]["introduced"], true);
        assert_eq!(json_val["findings"][1]["introduced"], false);
    }

    #[test]
    fn annotate_health_json_keeps_the_typed_complexity_flag() {
        let root = root();
        let path = root.join("src/other.ts");
        let mut report = make_health_report(&[(&path, "render")]);
        // The metric comparison found a worse value for an inherited key.
        report.findings[0].introduced = Some(true);
        let base = FxHashSet::from_iter(["complexity:src/other.ts:render".to_string()]);
        let mut json_val = json!({ "findings": [{}] });

        annotate_health_json(&mut json_val, &report, &root, &base);

        assert_eq!(json_val["findings"][0]["introduced"], true);
    }

    #[test]
    fn annotate_health_json_is_noop_when_findings_key_absent() {
        let root = root();
        let report = make_health_report(&[]);
        let base = FxHashSet::default();
        let mut json_val = json!({"summary": {}});
        let original = json_val.clone();

        annotate_health_json(&mut json_val, &report, &root, &base);

        assert_eq!(json_val, original);
    }

    // --- annotate_dupes_json and dupe_group_key ---

    fn make_clone_group(files: &[PathBuf], fragment: &str) -> CloneGroup {
        CloneGroup {
            instances: files
                .iter()
                .map(|f| CloneInstance {
                    is_symlink: false,
                    file: f.clone(),
                    start_line: 1,
                    end_line: 5,
                    start_col: 0,
                    end_col: 80,
                    fragment: fragment.to_string(),
                })
                .collect(),
            token_count: 10,
            line_count: 5,
            similarity: None,
        }
    }

    fn make_duplication_report(groups: Vec<CloneGroup>) -> DuplicationReport {
        DuplicationReport {
            clone_groups: groups,
            clone_families: Vec::new(),
            mirrored_directories: Vec::new(),
            stats: fallow_types::duplicates::DuplicationStats::default(),
        }
    }

    #[test]
    fn dupe_group_key_is_stable_for_sorted_deduplicated_files() {
        let root = root();
        let a = root.join("src/a.ts");
        let b = root.join("src/b.ts");
        // Build two groups with same fragment but different file order.
        let group_ab = make_clone_group(&[a.clone(), b.clone()], "const x = 1;");
        let group_ba = make_clone_group(&[b, a], "const x = 1;");
        let key_ab = dupe_group_key(&group_ab, &root);
        let key_ba = dupe_group_key(&group_ba, &root);
        // File list is sorted so both keys share the same file prefix.
        assert!(key_ab.starts_with("dupe:src/a.ts|src/b.ts:"));
        assert!(key_ba.starts_with("dupe:src/a.ts|src/b.ts:"));
        // Same fragment => same hash.
        assert_eq!(key_ab, key_ba);
    }

    #[test]
    fn preexisting_dupe_group_keys_collects_only_groups_outside_added_lines() {
        let root = root();
        let a = root.join("src/a.ts");
        let b = root.join("src/b.ts");
        let c = root.join("src/c.ts");
        // Instances span lines 1..=5. The diff adds line 3 in src/c.ts only.
        let untouched = make_clone_group(&[a.clone(), b], "shared scaffolding");
        let touched = make_clone_group(&[a, c], "pasted block");
        let diff = fallow_output::DiffIndex::from_unified_diff(
            "diff --git a/src/c.ts b/src/c.ts\n--- a/src/c.ts\n+++ b/src/c.ts\n@@ -3,0 +3,1 @@\n+const added = 1;\n",
        );

        let demote = super::preexisting_dupe_group_keys([&untouched, &touched], &root, &diff);

        assert!(demote.contains(&dupe_group_key(&untouched, &root)));
        assert!(!demote.contains(&dupe_group_key(&touched, &root)));
        assert_eq!(demote.len(), 1);
    }

    #[test]
    fn demote_introductions_moves_introduced_keys_to_inherited() {
        let base: FxHashSet<String> = std::iter::once("dupe:old".to_string()).collect();
        let mut ledger = AuditDomainLedger::compare(
            ["dupe:kept".to_string(), "dupe:demoted".to_string()],
            Some(&base),
        );
        assert_eq!(ledger.introduced_count(), 2);

        let demote: FxHashSet<String> = std::iter::once("dupe:demoted".to_string()).collect();
        ledger.demote_introductions(&demote);

        assert_eq!(ledger.introduced_count(), 1);
        assert_eq!(ledger.inherited_count(), 1);
        let introduced: Vec<bool> = ledger.introduced().collect();
        assert_eq!(introduced, vec![true, false]);
        assert_eq!(ledger.demoted_count(), 1);
        assert!(ledger.demoted_count() <= ledger.inherited_count());
        assert!(ledger.demoted_keys().contains("dupe:demoted"));
        let demoted: Vec<bool> = ledger.demoted().collect();
        assert_eq!(demoted, vec![false, true]);
    }

    #[test]
    fn demote_introductions_ignores_keys_that_were_not_introduced() {
        let base: FxHashSet<String> = std::iter::once("dupe:old".to_string()).collect();
        let mut ledger = AuditDomainLedger::compare(
            ["dupe:old".to_string(), "dupe:new".to_string()],
            Some(&base),
        );

        let demote: FxHashSet<String> = std::iter::once("dupe:old".to_string()).collect();
        ledger.demote_introductions(&demote);

        assert_eq!(ledger.demoted_count(), 0);
        let demoted: Vec<bool> = ledger.demoted().collect();
        assert_eq!(demoted, vec![false, false]);
    }

    #[test]
    fn annotate_domain_demotions_json_marks_only_demoted_entries() {
        let mut json_val = json!({
            "clone_groups": [{}, {}],
        });

        super::annotate_domain_demotions_json(
            &mut json_val,
            "clone_groups",
            [false, true],
            crate::CloneDemotionReason::NoAddedLines,
        );

        assert!(json_val["clone_groups"][0].get("demotion_reason").is_none());
        assert_eq!(
            json_val["clone_groups"][1]["demotion_reason"],
            "no-added-lines"
        );
    }

    #[test]
    fn dupes_keys_produces_one_key_per_clone_group() {
        let root = root();
        let a = root.join("src/a.ts");
        let b = root.join("src/b.ts");
        let groups = vec![
            make_clone_group(&[a.clone(), b.clone()], "block one"),
            make_clone_group(&[a, b], "block two"),
        ];
        let report = make_duplication_report(groups);
        let keys = dupes_keys(&report, &root);
        assert_eq!(keys.len(), 2);
    }

    #[test]
    fn annotate_dupes_json_marks_introduced_and_inherited_flags() {
        let root = root();
        let a = root.join("src/a.ts");
        let b = root.join("src/b.ts");
        let group_new = make_clone_group(&[a.clone(), b.clone()], "new block");
        let group_old = make_clone_group(&[a, b], "old block");
        let old_key = dupe_group_key(&group_old, &root);
        let base = FxHashSet::from_iter([old_key]);
        let report = make_duplication_report(vec![group_new, group_old]);
        let mut json_val = json!({
            "clone_groups": [{}, {}],
        });

        annotate_dupes_json(&mut json_val, &report, &root, &base);

        assert_eq!(json_val["clone_groups"][0]["introduced"], true);
        assert_eq!(json_val["clone_groups"][1]["introduced"], false);
    }

    #[test]
    fn annotate_dupes_json_is_noop_when_clone_groups_key_absent() {
        let root = root();
        let report = make_duplication_report(Vec::new());
        let base = FxHashSet::default();
        let mut json_val = json!({"stats": {}});
        let original = json_val.clone();

        annotate_dupes_json(&mut json_val, &report, &root, &base);

        assert_eq!(json_val, original);
    }

    // --- retain_introduced_dead_code with None base (no-op path, line 1127) ---

    #[test]
    fn retain_introduced_dead_code_is_noop_when_base_is_none() {
        let root = root();
        let mut results = sample_results(&root);
        let original_file_count = results.unused_files.len();
        let original_export_count = results.unused_exports.len();

        retain_introduced_dead_code(&mut results, &root, None);

        // Nothing should be filtered when base is None.
        assert_eq!(results.unused_files.len(), original_file_count);
        assert_eq!(results.unused_exports.len(), original_export_count);
    }

    // --- retain_introduced_dead_code covers framework / component / graph findings ---

    #[test]
    fn retain_introduced_dead_code_filters_framework_findings() {
        let root = root();
        let src = root.join("src/App.vue");
        let mut results = AnalysisResults::default();
        results
            .unprovided_injects
            .push(UnprovidedInjectFinding::with_actions(UnprovidedInject {
                path: src.clone(),
                key_name: "existing".to_string(),
                framework: "vue".to_string(),
                line: 1,
                col: 0,
            }));
        results
            .unprovided_injects
            .push(UnprovidedInjectFinding::with_actions(UnprovidedInject {
                path: src.clone(),
                key_name: "new".to_string(),
                framework: "vue".to_string(),
                line: 2,
                col: 0,
            }));
        results
            .unrendered_components
            .push(UnrenderedComponentFinding::with_actions(
                UnrenderedComponent {
                    path: src,
                    component_name: "OldWidget".to_string(),
                    framework: "vue".to_string(),
                    reachable_via: None,
                    line: 1,
                    col: 0,
                },
            ));

        let base = FxHashSet::from_iter([
            "unprovided-inject:src/App.vue:existing".to_string(),
            "unrendered-component:src/App.vue:OldWidget".to_string(),
        ]);

        retain_introduced_dead_code(&mut results, &root, Some(&base));

        // Only "new" inject survives; OldWidget is filtered.
        assert_eq!(results.unprovided_injects.len(), 1);
        assert_eq!(results.unprovided_injects[0].inject.key_name, "new");
        assert!(results.unrendered_components.is_empty());
    }

    #[test]
    fn retain_introduced_dead_code_filters_graph_findings() {
        let root = root();
        let a = root.join("src/a.ts");
        let b = root.join("src/b.ts");
        let mut results = AnalysisResults::default();
        results
            .circular_dependencies
            .push(CircularDependencyFinding::with_actions(
                CircularDependency {
                    files: vec![a.clone(), b],
                    length: 2,
                    line: 1,
                    col: 0,
                    edges: Vec::new(),
                    is_cross_package: false,
                },
            ));
        results
            .re_export_cycles
            .push(ReExportCycleFinding::with_actions(ReExportCycle {
                files: vec![a],
                kind: ReExportCycleKind::SelfLoop,
            }));

        // The circular dep is in the base; the re-export cycle is new.
        let base = FxHashSet::from_iter(["circular-dependency:src/a.ts|src/b.ts".to_string()]);

        retain_introduced_dead_code(&mut results, &root, Some(&base));

        assert!(results.circular_dependencies.is_empty());
        assert_eq!(results.re_export_cycles.len(), 1);
    }

    #[test]
    fn audit_ledger_routes_override_severity_and_persists_introduced_flags() {
        let root = root();
        let config: FallowConfig = serde_json::from_value(json!({
            "rules": { "unused-exports": "warn" },
            "overrides": [{
                "files": ["src/generated/**"],
                "rules": { "unused-exports": "error" }
            }]
        }))
        .expect("config");
        let config = config.resolve(root.clone(), OutputFormat::Json, 1, false, true, None);
        let mut results = AnalysisResults::default();
        results
            .unused_exports
            .push(export(&root.join("src/base.ts"), "baseExport"));
        results
            .unused_exports
            .push(export(&root.join("src/generated/new.ts"), "newExport"));
        let base = FxHashSet::from_iter(["unused-export:src/base.ts:baseExport".to_string()]);

        let ledger = dead_code_audit_ledger(&results, &root, &config, Some(&base));

        assert_eq!(ledger.classification_count(), 2);
        assert_eq!(ledger.introduced_count(), 1);
        assert_eq!(ledger.inherited_count(), 1);
        assert!(ledger.has_introduced_errors());
        assert!(!ledger.has_introduced_warnings());
        assert_eq!(ledger.records()[0].effective_severity, Severity::Warn);
        assert_eq!(ledger.records()[1].effective_severity, Severity::Error);

        ledger.annotate_results(&mut results);
        assert_eq!(ledger.classification_count(), 2);
        assert_eq!(
            results.unused_exports[0].introduced,
            Some(AuditIntroduced(false))
        );
        assert_eq!(
            results.unused_exports[1].introduced,
            Some(AuditIntroduced(true))
        );
    }

    #[test]
    fn audit_ledger_demotes_semantic_only_introductions_but_keeps_syntactic_new_findings() {
        let root = root();
        let config: FallowConfig = serde_json::from_value(json!({
            "rules": { "unused-exports": "error" }
        }))
        .expect("config");
        let config = config.resolve(root.clone(), OutputFormat::Json, 1, false, true, None);
        let mut results = AnalysisResults::default();
        // A pre-existing finding, a genuinely new syntactic finding, and a
        // semantic-only finding with no syntactic counterpart on head.
        results
            .unused_exports
            .push(export(&root.join("src/base.ts"), "baseExport"));
        results
            .unused_exports
            .push(export(&root.join("src/new.ts"), "newExport"));
        results
            .unused_exports
            .push(export(&root.join("src/semantic.ts"), "semanticOnly"));
        let base = FxHashSet::from_iter(["unused-export:src/base.ts:baseExport".to_string()]);
        let head_syntactic = FxHashSet::from_iter([
            "unused-export:src/base.ts:baseExport".to_string(),
            "unused-export:src/new.ts:newExport".to_string(),
        ]);

        let mut ledger = dead_code_audit_ledger(&results, &root, &config, Some(&base));
        assert_eq!(ledger.introduced_count(), 2);

        ledger.demote_unattributable_introductions(&head_syntactic);

        // Control: the genuinely new syntactic finding still gates.
        assert_eq!(ledger.introduced_count(), 1);
        assert!(ledger.has_introduced_errors());
        assert_eq!(ledger.inherited_count(), 2);
        ledger.annotate_results(&mut results);
        assert_eq!(
            results.unused_exports[0].introduced,
            Some(AuditIntroduced(false))
        );
        assert_eq!(
            results.unused_exports[1].introduced,
            Some(AuditIntroduced(true))
        );
        assert_eq!(
            results.unused_exports[2].introduced,
            Some(AuditIntroduced(false))
        );
    }

    #[test]
    fn audit_ledger_counts_each_occurrence_of_a_repeated_key() {
        let root = root();
        let config: FallowConfig = serde_json::from_value(json!({
            "rules": { "unused-exports": "error" }
        }))
        .expect("config");
        let config = config.resolve(root.clone(), OutputFormat::Json, 1, false, true, None);
        let mut results = AnalysisResults::default();
        results
            .unused_exports
            .push(export(&root.join("src/collision.ts"), "sameExport"));
        results
            .unused_exports
            .push(export(&root.join("src/collision.ts"), "sameExport"));

        let ledger = dead_code_audit_ledger(&results, &root, &config, Some(&FxHashSet::default()));

        assert_eq!(ledger.classification_count(), 2);
        assert_eq!(ledger.records().len(), 2);
        assert_eq!(ledger.introduced_count(), 2);
        assert_eq!(ledger.inherited_count(), 0);

        ledger.annotate_results(&mut results);
        assert!(
            results
                .unused_exports
                .iter()
                .all(|finding| { finding.introduced == Some(AuditIntroduced(true)) })
        );
    }

    #[test]
    fn audit_domain_ledger_counts_colliding_keys_once_but_preserves_record_membership() {
        let introduced = AuditDomainLedger::compare(
            ["same-key".to_string(), "same-key".to_string()],
            Some(&FxHashSet::default()),
        );
        assert_eq!(introduced.introduced_count(), 1);
        assert_eq!(introduced.inherited_count(), 0);
        assert_eq!(introduced.introduced().collect::<Vec<_>>(), [true, true]);

        let base = FxHashSet::from_iter(["same-key".to_string()]);
        let inherited = AuditDomainLedger::compare(
            ["same-key".to_string(), "same-key".to_string()],
            Some(&base),
        );
        assert_eq!(inherited.introduced_count(), 0);
        assert_eq!(inherited.inherited_count(), 1);
        assert_eq!(inherited.introduced().collect::<Vec<_>>(), [false, false]);
    }

    #[test]
    fn stale_suppression_fallback_preserves_introduced_annotation() {
        let root = root();
        let mut results = AnalysisResults::default();
        results.stale_suppressions.push(StaleSuppression {
            finding_id: None,
            path: root.join("src/new.ts"),
            line: 2,
            col: 0,
            origin: SuppressionOrigin::Comment {
                issue_kind: Some("unused-export".to_string()),
                reason: None,
                is_file_level: false,
                kind_known: true,
            },
            missing_reason: false,
            actions: StaleSuppression::actions_for(false),
            effective_severity: None,
        });
        let mut json = serde_json::to_value(&results).expect("json");

        annotate_stale_suppressions_json(&mut json, &results, &root, &FxHashSet::default());

        assert_eq!(json["stale_suppressions"][0]["introduced"], true);
    }

    #[test]
    fn remap_keys_for_renames_relocates_path_segments() {
        use rustc_hash::FxHashMap;

        let mut renames = FxHashMap::default();
        renames.insert(
            "src/old/impl.ts".to_string(),
            "src/renamed/impl.ts".to_string(),
        );

        let keys: FxHashSet<String> = [
            "complexity:src/old/impl.ts:complexFn:[Cyclomatic]".to_string(),
            "unused-export:src/old/impl.ts:unusedHelper".to_string(),
            "unused-file:src/old/impl.ts".to_string(),
            "unused-export:src/other.ts:src/old/impl.ts-unrelated".to_string(),
        ]
        .into_iter()
        .collect();

        let remapped = remap_keys_for_renames(&keys, &renames);

        assert!(remapped.contains("complexity:src/renamed/impl.ts:complexFn:[Cyclomatic]"));
        assert!(remapped.contains("unused-export:src/renamed/impl.ts:unusedHelper"));
        assert!(remapped.contains("unused-file:src/renamed/impl.ts"));
        assert!(
            remapped.contains("unused-export:src/other.ts:src/old/impl.ts-unrelated"),
            "non-exact segment matches must pass through untouched"
        );
    }

    #[test]
    fn remap_keys_for_renames_recanonicalizes_sorted_path_lists() {
        use rustc_hash::FxHashMap;

        let mut renames = FxHashMap::default();
        renames.insert("src/a.ts".to_string(), "src/z.ts".to_string());

        let keys: FxHashSet<String> = [
            // The base list was sorted as [src/a.ts, src/m.ts]; after the
            // rename the head list sorts as [src/m.ts, src/z.ts].
            "dupe:src/a.ts|src/m.ts:120:12:deadbeef".to_string(),
            "circular-dependency:src/a.ts|src/m.ts".to_string(),
        ]
        .into_iter()
        .collect();

        let remapped = remap_keys_for_renames(&keys, &renames);

        assert!(
            remapped.contains("dupe:src/m.ts|src/z.ts:120:12:deadbeef"),
            "duplicate-group file lists must be re-sorted: {remapped:#?}"
        );
        assert!(
            remapped.contains("circular-dependency:src/m.ts|src/z.ts"),
            "cycle file lists must be re-sorted: {remapped:#?}"
        );
    }

    #[test]
    fn remap_keys_for_renames_without_matches_is_identity() {
        use rustc_hash::FxHashMap;

        let mut renames = FxHashMap::default();
        renames.insert("src/elsewhere.ts".to_string(), "src/moved.ts".to_string());

        let keys: FxHashSet<String> =
            std::iter::once("unused-export:src/utils.ts:helper".to_string()).collect();

        assert_eq!(remap_keys_for_renames(&keys, &renames), keys);
    }

    /// One finding in each collection that no other fixture fills.
    fn production_and_directive_results(root: &Path) -> AnalysisResults {
        let page = root.join("src/app.ts");
        let mut results = AnalysisResults::default();
        results.dev_dependencies_in_production.push(
            DevDependencyInProductionFinding::with_actions(DevDependencyInProduction {
                package_name: "vite".to_string(),
                path: root.join("package.json"),
                line: 14,
            }),
        );
        results
            .invalid_client_exports
            .push(InvalidClientExportFinding::with_actions(
                InvalidClientExport {
                    path: page.clone(),
                    export_name: "config".to_string(),
                    directive: "use client".to_string(),
                    line: 3,
                    col: 0,
                },
            ));
        results
            .mixed_client_server_barrels
            .push(MixedClientServerBarrelFinding::with_actions(
                MixedClientServerBarrel {
                    path: page.clone(),
                    client_origin: "./client".to_string(),
                    server_origin: "./server".to_string(),
                    line: 1,
                    col: 0,
                },
            ));
        results
            .misplaced_directives
            .push(MisplacedDirectiveFinding::with_actions(
                MisplacedDirective {
                    path: page,
                    directive: "use server".to_string(),
                    line: 5,
                    col: 2,
                },
            ));
        results
    }

    /// Every finding of the fixtures, each as its own result set, so a
    /// disagreement names one collection.
    fn isolated_findings(fixtures: &[AnalysisResults]) -> Vec<(String, AnalysisResults)> {
        let mut isolated = Vec::new();
        for fixture in fixtures {
            let value = serde_json::to_value(fixture).expect("results serialize");
            let object = value.as_object().expect("results serialize as an object");
            for (collection, items) in object {
                let Some(items) = items.as_array() else {
                    continue;
                };
                for item in items {
                    let mut single = serde_json::to_value(AnalysisResults::default())
                        .expect("empty results serialize");
                    single[collection.as_str()] = serde_json::Value::Array(vec![item.clone()]);
                    let results = serde_json::from_value(single)
                        .unwrap_or_else(|error| panic!("{collection} round-trips: {error}"));
                    isolated.push((collection.clone(), results));
                }
            }
        }
        isolated
    }

    fn absent_component_prop_results(root: &Path) -> AnalysisResults {
        let mut results = AnalysisResults::default();
        results
            .absent_component_props
            .push(AbsentComponentPropFinding::with_actions(
                AbsentComponentProp {
                    path: root.join("src/App.vue"),
                    component_name: "MyModal".into(),
                    framework: "vue".into(),
                    prop_name: "highlight".into(),
                    line: 3,
                    col: 2,
                    has_default: true,
                    inspected_call_sites: vec![ComponentPropCallSite {
                        path: root.join("src/page.ts"),
                        line: 8,
                        col: 0,
                    }],
                    explanation: "Review known callers and API intent.".into(),
                },
            ));
        results
    }

    /// A config that sets every rule by `base` and, for the files of the
    /// fixtures that an `overrides` entry matches, by `scoped`. Each pair
    /// gives the severity of the rules at an even and at an odd position, so
    /// a finding that reads the rule of another kind shows as a difference.
    fn every_rule_config(
        base: [&str; 2],
        scoped: Option<[&str; 2]>,
    ) -> fallow_config::ResolvedConfig {
        let every_rule = |severities: [&str; 2]| {
            let rules = serde_json::to_value(fallow_config::RulesConfig::default())
                .expect("rules serialize");
            let names = rules
                .as_object()
                .expect("rules serialize as an object")
                .keys();
            serde_json::Value::Object(
                names
                    .enumerate()
                    .map(|(index, name)| (name.clone(), json!(severities[index % 2])))
                    .collect(),
            )
        };
        let mut config = json!({ "rules": every_rule(base) });
        if let Some(scoped) = scoped {
            config["overrides"] = json!([{
                "files": [
                    "package.json",
                    "pnpm-workspace.yaml",
                    "src/app.ts",
                    "src/page.ts",
                    "src/types.ts",
                    "src/App.vue",
                    "src/actions/**",
                    "app/**",
                    "src/app/**",
                    "src/store.ts"
                ],
                "rules": every_rule(scoped)
            }]);
        }
        let config: FallowConfig = serde_json::from_value(config).expect("config");
        config.resolve(root(), OutputFormat::Json, 1, false, true, None)
    }

    /// The audit ledger and the exit-code rule resolve severity in two
    /// places. With every finding introduced, the ledger must report an
    /// error exactly when `has_error_severity_issues` does, for every
    /// collection, with and without `overrides`.
    #[test]
    fn audit_ledger_errors_match_the_exit_code_rule_for_every_collection() {
        let root = root();
        // Two arrays keep each stack array under the large-array lint limit.
        let fixtures: Vec<AnalysisResults> = [
            sample_results(&root),
            graph_boundary_catalog_override_results(&root),
            type_member_and_dependency_results(&root),
            framework_inject_and_render_results(&root),
            absent_component_prop_results(&root),
        ]
        .into_iter()
        .chain([
            server_action_load_data_and_route_results(&root),
            angular_input_output_and_policy_results(&root),
            unused_store_member_results(&root),
            production_and_directive_results(&root),
            AnalysisResults {
                prop_drilling_chains: vec![PropDrillingChainFinding::with_actions(
                    PropDrillingChain {
                        prop: "user".to_owned(),
                        depth: 3,
                        hops: vec![PropDrillHop {
                            file: root.join("src/page.ts"),
                            line: 4,
                            component: "Page".to_owned(),
                        }],
                    },
                )],
                ..effect_results(&root)
            },
        ])
        .collect();
        let findings = isolated_findings(&fixtures);
        let empty_base = FxHashSet::default();
        let mut covered = std::collections::BTreeSet::new();
        let mut mismatches = Vec::new();
        for (base, scoped) in [
            (["error", "error"], None),
            (["warn", "warn"], None),
            (["error", "warn"], None),
            (["error", "error"], Some(["warn", "warn"])),
            (["warn", "warn"], Some(["error", "error"])),
            (["off", "off"], Some(["error", "error"])),
            (["error", "warn"], Some(["warn", "error"])),
            (["warn", "error"], Some(["error", "warn"])),
        ] {
            let config = every_rule_config(base, scoped);
            for (collection, results) in &findings {
                let ledger = dead_code_audit_ledger(results, &root, &config, Some(&empty_base));
                covered.extend(ledger.records().iter().map(|record| record.collection));
                let exit_rule = fallow_engine::error_severity::has_error_severity_issues(
                    results,
                    &config.rules,
                    Some(&config),
                    false,
                );
                if ledger.has_introduced_errors() != exit_rule {
                    mismatches.push(format!(
                        "{collection} (rules {base:?}, overrides {scoped:?}): ledger {}, exit rule {exit_rule}",
                        ledger.has_introduced_errors()
                    ));
                }
            }
        }
        assert!(mismatches.is_empty(), "{}", mismatches.join("\n"));
        let missing: Vec<&str> = super::AuditCollection::ALL
            .iter()
            .map(|collection| collection.json_key())
            .filter(|key| !covered.contains(key))
            .collect();
        assert!(
            missing.is_empty(),
            "the fixtures hold no finding in {missing:?}"
        );
    }

    // Line-free, count-aware audit keys.

    fn audit_suppression(root: &Path, line: u32, reason: Option<&str>) -> StaleSuppression {
        StaleSuppression {
            finding_id: None,
            path: root.join("src/flags.ts"),
            line,
            col: 0,
            origin: SuppressionOrigin::Comment {
                issue_kind: Some("unused-export".to_string()),
                reason: reason.map(str::to_owned),
                is_file_level: false,
                kind_known: true,
            },
            missing_reason: false,
            actions: StaleSuppression::actions_for(false),
            effective_severity: None,
        }
    }

    /// Add `by` to the line of every finding whose old audit key held a line.
    fn shift_lines(results: &mut AnalysisResults, by: u32) {
        for item in &mut results.unlisted_dependencies {
            for site in &mut item.dep.imported_from {
                site.line += by;
            }
        }
        for item in &mut results.stale_suppressions {
            item.line += by;
        }
        for item in &mut results.unused_catalog_entries {
            item.entry.line += by;
        }
        for item in &mut results.empty_catalog_groups {
            item.group.line += by;
        }
        for item in &mut results.unresolved_catalog_references {
            item.reference.line += by;
        }
        for item in &mut results.unused_dependency_overrides {
            item.entry.line += by;
        }
        for item in &mut results.misconfigured_dependency_overrides {
            item.entry.line += by;
        }
        for item in &mut results.misplaced_directives {
            item.directive_site.line += by;
        }
        for item in &mut results.unused_exports {
            item.export.line += by;
        }
    }

    fn line_sensitive_results(root: &Path) -> AnalysisResults {
        let mut results = graph_boundary_catalog_override_results(root);
        let sample = sample_results(root);
        results.unlisted_dependencies = sample.unlisted_dependencies;
        results.unused_exports = sample.unused_exports;
        results
            .misplaced_directives
            .push(MisplacedDirectiveFinding::with_actions(
                MisplacedDirective {
                    path: root.join("src/action.ts"),
                    directive: "use server".to_string(),
                    line: 4,
                    col: 0,
                },
            ));
        results
    }

    #[test]
    fn dead_code_keys_do_not_change_when_lines_shift() {
        let root = root();
        let before = line_sensitive_results(&root);
        let mut after = before.clone();
        shift_lines(&mut after, 20);

        let before_keys = dead_code_keys(&before, &root);
        let after_keys = dead_code_keys(&after, &root);

        let mut changed: Vec<&String> = after_keys.difference(&before_keys).collect();
        changed.sort();
        assert!(changed.is_empty(), "keys that hold a line: {changed:?}");
    }

    #[test]
    fn stale_suppression_keys_ignore_the_reason_text() {
        let root = root();
        let with_reason = |reason: &str| AnalysisResults {
            stale_suppressions: vec![audit_suppression(&root, 3, Some(reason))],
            ..AnalysisResults::default()
        };

        assert_eq!(
            dead_code_keys(&with_reason("kept for the plugin API"), &root),
            dead_code_keys(&with_reason("removed in v3"), &root)
        );
    }

    #[test]
    fn unlisted_dependency_keys_ignore_the_import_sites() {
        let root = root();
        let base = sample_results(&root);
        let mut head = base.clone();
        let item = &mut head.unlisted_dependencies[0].dep;
        item.imported_from[0].line = 40;
        item.imported_from.push(ImportSite {
            path: root.join("src/other.ts"),
            line: 1,
            col: 0,
        });

        assert_eq!(dead_code_keys(&base, &root), dead_code_keys(&head, &root));
    }

    #[test]
    fn a_second_occurrence_of_an_inherited_key_is_introduced() {
        let root = root();
        let config: FallowConfig = serde_json::from_value(json!({
            "rules": { "stale-suppressions": "error" }
        }))
        .expect("config");
        let config = config.resolve(root.clone(), OutputFormat::Json, 1, false, true, None);
        let base_results = AnalysisResults {
            stale_suppressions: vec![audit_suppression(&root, 3, None)],
            ..AnalysisResults::default()
        };
        let base = dead_code_keys(&base_results, &root);
        let mut head = AnalysisResults {
            stale_suppressions: vec![
                audit_suppression(&root, 13, None),
                audit_suppression(&root, 17, None),
            ],
            ..AnalysisResults::default()
        };

        let ledger = dead_code_audit_ledger(&head, &root, &config, Some(&base));
        assert_eq!(ledger.introduced_count(), 1);
        assert_eq!(ledger.inherited_count(), 1);
        assert!(!ledger.records()[0].introduced);
        assert!(ledger.records()[1].introduced);

        retain_introduced_dead_code(&mut head, &root, Some(&base));
        assert_eq!(head.stale_suppressions.len(), 1);
        assert_eq!(head.stale_suppressions[0].line, 17);
    }

    #[test]
    fn a_renamed_file_keeps_its_findings_and_occurrences_inherited() {
        let root = root();
        let finding = |path: &str, line: u32| {
            let mut suppression = audit_suppression(&root, line, None);
            suppression.path = root.join(path);
            suppression
        };
        let base_results = AnalysisResults {
            stale_suppressions: vec![finding("src/old.ts", 3), finding("src/old.ts", 9)],
            ..AnalysisResults::default()
        };
        let head = AnalysisResults {
            stale_suppressions: vec![finding("src/new.ts", 4), finding("src/new.ts", 10)],
            ..AnalysisResults::default()
        };
        let renames = rustc_hash::FxHashMap::from_iter([(
            "src/old.ts".to_string(),
            "src/new.ts".to_string(),
        )]);

        let base = remap_keys_for_renames(&dead_code_keys(&base_results, &root), &renames);

        assert_eq!(base, dead_code_keys(&head, &root));
    }
}