slopguard_core/

scanner.rs

use std::collections::HashMap;
use std::fs::{self, read_to_string};
use std::path::{Path, PathBuf};

use ast_grep_config::{
    CombinedScan, GlobalRules, RuleCollection, RuleConfig, RuleConfigError, SerializableRuleConfig,
};
use ast_grep_core::tree_sitter::LanguageExt;
use ast_grep_core::Language as AstLanguage;
use ast_grep_core::{AstGrep, Doc};
use ast_grep_language::SupportLang;
use globset::{Error as GlobError, Glob, GlobSet, GlobSetBuilder};
use ignore::WalkBuilder;
use rayon::prelude::*;
use serde::Serialize;
use serde_yaml::with::singleton_map_recursive;
use serde_yaml::{to_value, Value};
use strum::IntoEnumIterator;
use thiserror::Error;

use crate::cache::{file_content_hash, rules_hash, CacheEntry, CacheStore};
use crate::config::Config;
use crate::cross_file::{self, CrossFileKind, DeclFilter, FileSymbols, SymbolIndex};
use crate::disable::filter_disabled;
use crate::finding::{CacheStats, Finding, ScanResult, ScanStats};
use crate::metric::{self, Metric};
use crate::rule::{Language, Rule, RuleId, Severity};
use crate::test_filter::{is_test_path, CfgTestRanges};

#[derive(Debug, Error)]
pub enum ScanError {
    #[error("failed to compile rule '{id}': {source}")]
    RuleCompile {
        id: RuleId,
        #[source]
        source: RuleConfigError,
    },

    #[error("invalid glob pattern: {0}")]
    Glob(#[from] GlobError),

    #[error("rule '{id}': metric rule is missing a threshold")]
    InvalidMetricRule { id: RuleId },
}

/// The subset of a slopguard rule that ast-grep understands. slopguard-only
/// fields (`category`, `fix` as free text, `tests`) are deliberately left out.
#[derive(Serialize)]
pub struct AstGrepRule<'a> {
    pub id: &'a str,
    pub language: SupportLang,
    pub severity: &'a Severity,
    pub message: &'a str,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub note: Option<&'a str>,
    pub rule: &'a Value,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub files: Option<&'a [String]>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub ignores: Option<&'a [String]>,
}

/// Rules compiled for scanning, plus a way back to the slopguard rule that
/// produced each ast-grep config.
struct CompiledRules<'a> {
    collection: RuleCollection<SupportLang>,
    by_id: HashMap<(&'a str, Language), &'a Rule>,
    metrics: Vec<MetricRule<'a>>,
    cross_file: Vec<CrossFileRule<'a>>,
}

/// A cross-file rule prepared for scanning: kind resolved and the declaration
/// filter compiled once.
struct CrossFileRule<'a> {
    rule: &'a Rule,
    kind: CrossFileKind,
    decl_filter: DeclFilter,
}

/// A metric rule prepared for scanning: threshold resolved and `files` /
/// `ignores` globs compiled once. ast-grep applies those globs for AST rules;
/// metric rules are evaluated outside ast-grep so they apply them here.
struct MetricRule<'a> {
    rule: &'a Rule,
    metric: Metric,
    threshold: f64,
    files: Option<GlobSet>,
    ignores: Option<GlobSet>,
}

impl MetricRule<'_> {
    fn applies_to(&self, path: &Path, lang: &Language) -> bool {
        self.rule.language == *lang
            && self.files.as_ref().is_none_or(|g| g.is_match(path))
            && !self.ignores.as_ref().is_some_and(|g| g.is_match(path))
    }
}

fn extension_to_lang(path: &Path) -> Option<SupportLang> {
    SupportLang::from_path(path)
        .filter(|lang| Language::iter().any(|l| l.ast_grep_langs().contains(lang)))
}

fn support_lang_to_language(lang: SupportLang) -> Language {
    match lang {
        SupportLang::Rust => Language::Rust,
        _ => Language::TypeScript,
    }
}

pub(crate) fn compile_ast_grep_rule(
    rule: &AstGrepRule,
) -> Result<RuleConfig<SupportLang>, RuleConfigError> {
    let inner: SerializableRuleConfig<SupportLang> = to_value(rule)
        .and_then(singleton_map_recursive::deserialize)
        .map_err(RuleConfigError::from)?;
    RuleConfig::try_from(inner, &GlobalRules::default())
}

fn compile_rule(rule: &Rule, lang: SupportLang) -> Result<RuleConfig<SupportLang>, ScanError> {
    let ast_grep_rule = AstGrepRule {
        id: rule.id.as_str(),
        language: lang,
        severity: &rule.severity,
        message: &rule.message,
        note: rule.note.as_deref(),
        rule: &rule.rule,
        files: rule.files.as_deref(),
        ignores: rule.ignores.as_deref(),
    };
    compile_ast_grep_rule(&ast_grep_rule).map_err(|source| ScanError::RuleCompile {
        id: rule.id.clone(),
        source,
    })
}

/// Resolve a metric rule's threshold and compile its path globs.
fn build_metric_rule(rule: &Rule) -> Result<MetricRule<'_>, ScanError> {
    let Some((metric, threshold)) = rule.metric_spec() else {
        return Err(ScanError::InvalidMetricRule {
            id: rule.id.clone(),
        });
    };
    Ok(MetricRule {
        rule,
        metric,
        threshold,
        files: rule.files.as_deref().map(build_glob_set).transpose()?,
        ignores: rule.ignores.as_deref().map(build_glob_set).transpose()?,
    })
}

/// Compile the globs that bound which declarations a cross-file rule may
/// report. The `kind` is resolved by the caller, which already partitioned the
/// rules on `is_cross_file()`.
fn build_cross_file_rule(rule: &Rule, kind: CrossFileKind) -> Result<CrossFileRule<'_>, ScanError> {
    Ok(CrossFileRule {
        rule,
        kind,
        decl_filter: DeclFilter {
            files: rule.files.as_deref().map(build_glob_set).transpose()?,
            ignores: rule.ignores.as_deref().map(build_glob_set).transpose()?,
            skip_test_code: rule.skip_test_code,
        },
    })
}

fn compile_rules(rules: &[Rule]) -> Result<CompiledRules<'_>, ScanError> {
    // Neither cross-file nor metric rules may reach ast-grep: their `rule`
    // field is null and would fail to compile.
    let (cross_rules, rest): (Vec<&Rule>, Vec<&Rule>) =
        rules.iter().partition(|r| r.is_cross_file());
    let (metric_rules, ast_rules): (Vec<&Rule>, Vec<&Rule>) =
        rest.into_iter().partition(|r| r.is_metric());

    let configs = ast_rules
        .iter()
        .copied()
        .flat_map(|rule| {
            rule.language
                .ast_grep_langs()
                .iter()
                .map(move |lang| compile_rule(rule, *lang))
        })
        .collect::<Result<Vec<_>, _>>()?;
    Ok(CompiledRules {
        collection: RuleCollection::try_new(configs)?,
        by_id: ast_rules
            .iter()
            .copied()
            .map(|rule| ((rule.id.as_str(), rule.language.clone()), rule))
            .collect::<HashMap<_, _>>(),
        metrics: metric_rules
            .into_iter()
            .map(build_metric_rule)
            .collect::<Result<Vec<_>, _>>()?,
        cross_file: cross_rules
            .into_iter()
            .filter_map(|rule| rule.cross_file_kind().map(|kind| (rule, kind)))
            .map(|(rule, kind)| build_cross_file_rule(rule, kind))
            .collect::<Result<Vec<_>, _>>()?,
    })
}

fn build_glob_set(patterns: &[String]) -> Result<GlobSet, GlobError> {
    let mut builder = GlobSetBuilder::new();
    for pattern in patterns {
        builder.add(Glob::new(pattern)?);
    }
    builder.build()
}

/// One finding per metric rule whose measured value exceeds its threshold.
///
/// File-level findings have no source position, so they are anchored at 1:1.
/// `skip_test_code` drops the whole file: a line-1 finding can never be inside
/// a `#[cfg(test)]` block.
fn metric_findings<D: Doc>(
    metrics: &[&MetricRule],
    path: &Path,
    root: &AstGrep<D>,
    source: &str,
    lang: &Language,
) -> Vec<Finding> {
    metrics
        .iter()
        .filter(|m| !(m.rule.skip_test_code && is_test_path(path)))
        .filter_map(|m| {
            let value = metric::compute(m.metric, lang, root, source);
            if !metric::exceeds(value, m.threshold) {
                return None;
            }
            let rendered = m.metric.format_value(value);
            Some(Finding {
                rule_id: m.rule.id.clone(),
                severity: m.rule.severity.clone(),
                category: m.rule.category.clone().unwrap_or_default(),
                message: m.rule.message.replace("$value", &rendered),
                note: m.rule.note.clone(),
                fix: m.rule.fix.clone(),
                file: path.to_path_buf(),
                line: 1,
                column: 1,
                end_line: 1,
                end_column: 1,
                matched_text: m.metric.describe(value),
                confidence: None,
                escalated: false,
            })
        })
        .collect()
}

/// One file's contribution to a scan: its findings plus, when a cross-file
/// rule is active, the symbols it adds to the project index. Both come out of
/// a single parse.
#[derive(Default)]
struct FileScan {
    findings: Vec<Finding>,
    symbols: FileSymbols,
}

fn scan_file(
    path: &Path,
    lang: SupportLang,
    rules: &CompiledRules,
    collect_symbols: bool,
) -> FileScan {
    let rule_lang = support_lang_to_language(lang);
    let applicable = rules.collection.get_rule_from_lang(path, lang);
    let metrics: Vec<&MetricRule> = rules
        .metrics
        .iter()
        .filter(|m| m.applies_to(path, &rule_lang))
        .collect();
    // A run scoped to a single cross-file rule has no ast-grep and no metric
    // rule, yet the file still has to be parsed for its symbols.
    let want_symbols = collect_symbols && lang == SupportLang::Rust;
    if applicable.is_empty() && metrics.is_empty() && !want_symbols {
        return FileScan::default();
    }
    let Ok(source) = read_to_string(path) else {
        return FileScan::default();
    };

    let root = lang.ast_grep(&source);
    // Built once and shared by the finding filter and the symbol extractor.
    let cfg_test = (lang == SupportLang::Rust).then(|| CfgTestRanges::from_root(&root));

    let mut findings: Vec<Finding> = if applicable.is_empty() {
        Vec::new()
    } else {
        let combined = CombinedScan::new(applicable);
        let result = combined.scan(&root, false);

        let cfg_test = cfg_test.as_ref();
        let is_test_file = is_test_path(path);

        result
            .matches
            .into_iter()
            .filter_map(|(config, matches)| {
                let rule = rules.by_id.get(&(config.id.as_str(), rule_lang.clone()))?;
                Some((*rule, matches))
            })
            .flat_map(|(rule, matches)| {
                let skip_test_code = rule.skip_test_code;
                matches
                    .into_iter()
                    .map(move |node_match| {
                        let start = node_match.start_pos();
                        let end = node_match.end_pos();
                        Finding {
                            rule_id: rule.id.clone(),
                            severity: rule.severity.clone(),
                            category: rule.category.clone().unwrap_or_default(),
                            message: rule.message.clone(),
                            note: rule.note.clone(),
                            fix: rule.fix.clone(),
                            file: path.to_path_buf(),
                            line: start.line() + 1,
                            column: start.byte_point().1 + 1,
                            end_line: end.line() + 1,
                            end_column: end.byte_point().1 + 1,
                            matched_text: node_match.text().to_string(),
                            confidence: None,
                            escalated: false,
                        }
                    })
                    .filter(move |f| {
                        if !skip_test_code {
                            return true;
                        }
                        let in_test_code =
                            is_test_file || cfg_test.is_some_and(|r| r.contains_line(f.line));
                        !in_test_code
                    })
            })
            .collect()
    };

    findings.extend(metric_findings(&metrics, path, &root, &source, &rule_lang));

    // Symbols are not run through `filter_disabled`: suppression applies to the
    // cross-file findings emitted later, against the declaration file's source.
    let symbols = match (want_symbols, cfg_test.as_ref()) {
        (true, Some(ranges)) => cross_file::extract_rust_symbols(&root, ranges),
        _ => FileSymbols::default(),
    };

    FileScan {
        findings: filter_disabled(findings, &source),
        symbols,
    }
}

/// Assemble the project index from every file's contribution, evaluate each
/// active cross-file rule, then drop the findings a disable comment suppresses
/// in the file that declares the symbol.
fn cross_file_findings(
    rules: &[CrossFileRule<'_>],
    contributions: &[(PathBuf, FileSymbols)],
) -> Vec<Finding> {
    let index = SymbolIndex::build(contributions.iter().map(|(p, s)| (p.as_path(), s)));
    let mut by_file: HashMap<PathBuf, Vec<Finding>> = HashMap::new();
    for rule in rules {
        let found = cross_file::evaluate(rule.rule, rule.kind, &index, &rule.decl_filter);
        for finding in found {
            by_file
                .entry(finding.file.clone())
                .or_default()
                .push(finding);
        }
    }
    by_file
        .into_iter()
        .flat_map(|(path, findings)| match read_to_string(&path) {
            // A file that can no longer be read keeps its findings unfiltered
            // rather than losing them.
            Ok(source) => filter_disabled(findings, &source),
            Err(_) => findings,
        })
        .collect()
}

/// Run the cross-file pass and append its findings, if it is due. A full scan
/// asks for it via `run_cross_file`; a partial scan (`--diff`, explicit files)
/// collects contributions to warm the cache but leaves the index incomplete, so
/// it must not evaluate. Centralises the `run_cross_file && has cross-file
/// rules` invariant shared by both scan paths.
fn append_cross_file(
    findings: &mut Vec<Finding>,
    compiled: &CompiledRules,
    run_cross_file: bool,
    contributions: &[(PathBuf, FileSymbols)],
) {
    if run_cross_file && !compiled.cross_file.is_empty() {
        findings.extend(cross_file_findings(&compiled.cross_file, contributions));
    }
}

/// Walk `paths` (gitignore-aware) and keep the source files slopguard can parse.
fn walk_files(paths: &[PathBuf], ignores: &GlobSet) -> Vec<(PathBuf, SupportLang)> {
    paths
        .iter()
        .flat_map(|path| WalkBuilder::new(path).build().flatten())
        .filter(|entry| entry.file_type().is_some_and(|t| t.is_file()))
        .map(|entry| entry.into_path())
        .filter(|path| !ignores.is_match(path))
        .filter_map(|path| extension_to_lang(&path).map(|lang| (path, lang)))
        .collect()
}

/// Keep the given files as-is (no directory walk), dropping the ones that are
/// ignored by config or written in an unsupported language.
///
/// Deliberately not gitignore-aware: a file git reports as changed must be
/// scanned even when it lives under a hidden or ignored directory.
fn explicit_files(files: &[PathBuf], ignores: &GlobSet) -> Vec<(PathBuf, SupportLang)> {
    files
        .iter()
        .filter(|path| path.is_file())
        .filter(|path| !ignores.is_match(path))
        .filter_map(|path| extension_to_lang(path).map(|lang| (path.clone(), lang)))
        .collect()
}

/// Count errors and warnings in one pass.
pub fn count_severities(findings: &[Finding]) -> (usize, usize) {
    let mut errors = 0;
    let mut warnings = 0;
    for finding in findings {
        match finding.severity {
            Severity::Error => errors += 1,
            Severity::Warning => warnings += 1,
        }
    }
    (errors, warnings)
}

/// Sort findings by location and drop duplicates from overlapping rules.
fn normalize_findings(findings: &mut Vec<Finding>) {
    findings.sort_by(|a, b| (&a.file, a.line, a.column).cmp(&(&b.file, b.line, b.column)));
    findings.dedup_by(|a, b| {
        a.rule_id == b.rule_id && a.file == b.file && a.line == b.line && a.column == b.column
    });
}

/// Scan an already-collected file list without touching the cache.
///
/// Symbol collection is driven by the active rules alone, never by
/// `run_cross_file`: a partial scan must still cache a complete contribution.
fn scan_collected(
    files: Vec<(PathBuf, SupportLang)>,
    compiled: &CompiledRules,
    run_cross_file: bool,
) -> ScanResult {
    let collect_symbols = !compiled.cross_file.is_empty();
    let scans: Vec<(PathBuf, FileScan)> = files
        .par_iter()
        .map(|(path, lang)| {
            let scan = scan_file(path, *lang, compiled, collect_symbols);
            (path.clone(), scan)
        })
        .collect();

    let mut findings: Vec<Finding> = Vec::new();
    let mut contributions: Vec<(PathBuf, FileSymbols)> = Vec::new();
    for (path, scan) in scans {
        findings.extend(scan.findings);
        if collect_symbols {
            contributions.push((path, scan.symbols));
        }
    }
    append_cross_file(&mut findings, compiled, run_cross_file, &contributions);
    normalize_findings(&mut findings);

    let (errors, warnings) = count_severities(&findings);

    ScanResult {
        findings,
        stats: ScanStats {
            errors,
            warnings,
            total: errors + warnings,
            files_scanned: files.len(),
            baseline_filtered: 0,
            diff_base: None,
            files_changed: None,
        },
        cache_stats: None,
    }
}

/// Scan an already-collected file list, reusing cached findings for files
/// whose content hash is unchanged.
///
/// `prune` drops cache entries that no longer correspond to a scanned file. A
/// partial scan must pass `false`: it never saw the other files, so their
/// entries are still valid.
fn scan_collected_cached(
    files: Vec<(PathBuf, SupportLang)>,
    compiled: &CompiledRules,
    rules: &[Rule],
    cache_dir: &Path,
    prune: bool,
    run_cross_file: bool,
) -> ScanResult {
    let collect_symbols = !compiled.cross_file.is_empty();
    let current_rules_hash = rules_hash(rules);
    let store = CacheStore::with_dir(cache_dir.to_path_buf()).scoped_to_rules(&current_rules_hash);
    let rules_changed = store
        .check_rules_changed(&current_rules_hash)
        .unwrap_or(true);

    let file_contents: Vec<(PathBuf, SupportLang, Vec<u8>, String)> = files
        .into_iter()
        .filter_map(|(path, lang)| {
            let content = fs::read(&path).ok()?;
            let hash = file_content_hash(&content);
            Some((path, lang, content, hash))
        })
        .collect();

    let mut cached_count = 0usize;
    let mut changed_count = 0usize;
    let mut all_findings: Vec<Finding> = Vec::new();
    let mut contributions: Vec<(PathBuf, FileSymbols)> = Vec::new();

    struct FileWork {
        path: PathBuf,
        lang: SupportLang,
        hash: String,
    }

    let mut to_scan: Vec<FileWork> = Vec::new();

    for (path, lang, _content, hash) in file_contents.iter() {
        if !rules_changed {
            if let Some(entry) = store.get(hash) {
                cached_count += 1;
                all_findings.extend(entry.findings);
                if collect_symbols {
                    contributions.push((path.clone(), entry.symbols));
                }
                continue;
            }
        }
        changed_count += 1;
        to_scan.push(FileWork {
            path: path.clone(),
            lang: *lang,
            hash: hash.clone(),
        });
    }

    let scanned: Vec<(PathBuf, String, FileScan)> = to_scan
        .par_iter()
        .map(|work| {
            let scan = scan_file(&work.path, work.lang, compiled, collect_symbols);
            (work.path.clone(), work.hash.clone(), scan)
        })
        .collect();

    for (path, hash, scan) in scanned {
        let entry = CacheEntry {
            findings: scan.findings,
            symbols: scan.symbols,
        };
        store.put(&hash, &entry).ok();
        all_findings.extend(entry.findings);
        if collect_symbols {
            contributions.push((path, entry.symbols));
        }
    }

    // Cross-file evaluation itself is never cached: it re-runs on every scan
    // from the assembled index.
    append_cross_file(&mut all_findings, compiled, run_cross_file, &contributions);

    if prune {
        let current_hashes: Vec<String> =
            file_contents.iter().map(|(_, _, _, h)| h.clone()).collect();
        store.cleanup(&current_hashes).ok();
    }

    normalize_findings(&mut all_findings);

    let (errors, warnings) = count_severities(&all_findings);

    let files_scanned = cached_count + changed_count;

    ScanResult {
        findings: all_findings,
        stats: ScanStats {
            errors,
            warnings,
            total: errors + warnings,
            files_scanned,
            baseline_filtered: 0,
            diff_base: None,
            files_changed: None,
        },
        cache_stats: Some(CacheStats {
            cached: cached_count,
            changed: changed_count,
        }),
    }
}

/// Scan the given paths for rule violations.
pub fn scan(paths: &[PathBuf], rules: &[Rule], config: &Config) -> Result<ScanResult, ScanError> {
    let compiled = compile_rules(rules)?;
    let ignores = build_glob_set(&config.scan.ignores)?;
    Ok(scan_collected(walk_files(paths, &ignores), &compiled, true))
}

/// Scan with file-level caching. Files whose content hash matches a cached
/// entry (and whose rules have not changed) return cached findings without
/// reparsing.
///
/// `cache_dir` is the directory where cache files are stored. When a custom
/// cache directory is specified (via `--cache-dir`, `SLOPGUARD_CACHE_DIR`,
/// or `scan.cache_dir` in config), pass it directly. Otherwise pass the
/// project root and use `CacheStore::new` which appends `.slopguard-cache`.
pub fn scan_cached(
    paths: &[PathBuf],
    rules: &[Rule],
    config: &Config,
    cache_dir: &Path,
) -> Result<ScanResult, ScanError> {
    let compiled = compile_rules(rules)?;
    let ignores = build_glob_set(&config.scan.ignores)?;
    Ok(scan_collected_cached(
        walk_files(paths, &ignores),
        &compiled,
        rules,
        cache_dir,
        true,
        true,
    ))
}

/// Scan an explicit list of files instead of walking directories.
///
/// Used by `--diff`, where git already produced the exact file set. Paths that
/// no longer exist or that slopguard cannot parse are silently skipped.
///
/// Cross-file rules are not evaluated here. `--diff` sees only the changed
/// files, so the project index would be incomplete and its impl counts wrong.
/// Symbol contributions are still collected and cached, so a later full scan is
/// not penalised.
pub fn scan_files(
    files: &[PathBuf],
    rules: &[Rule],
    config: &Config,
) -> Result<ScanResult, ScanError> {
    let compiled = compile_rules(rules)?;
    let ignores = build_glob_set(&config.scan.ignores)?;
    Ok(scan_collected(
        explicit_files(files, &ignores),
        &compiled,
        false,
    ))
}

/// Cached variant of [`scan_files`]. Cache pruning is skipped: a partial scan
/// must not evict the entries of files it did not look at.
///
/// Cross-file rules are not evaluated here. `--diff` sees only the changed
/// files, so the project index would be incomplete and its impl counts wrong.
/// Symbol contributions are still collected and cached, so a later full scan is
/// not penalised.
pub fn scan_files_cached(
    files: &[PathBuf],
    rules: &[Rule],
    config: &Config,
    cache_dir: &Path,
) -> Result<ScanResult, ScanError> {
    let compiled = compile_rules(rules)?;
    let ignores = build_glob_set(&config.scan.ignores)?;
    Ok(scan_collected_cached(
        explicit_files(files, &ignores),
        &compiled,
        rules,
        cache_dir,
        false,
        false,
    ))
}

#[cfg(test)]
mod tests {
    use std::fs::{create_dir, write};

    use tempfile::tempdir;

    use super::*;
    use crate::rule::{load_builtin_rules, parse_rule, RuleId};

    fn unwrap_rule() -> Rule {
        parse_rule(
            r#"
id: test-unwrap
language: rust
severity: error
category: correctness
message: ".unwrap() forbidden"
rule:
  kind: call_expression
  regex: '\.unwrap\(\)\s*$'
"#,
        )
        .unwrap()
    }

    fn scan_dir(dir: &Path, rules: &[Rule]) -> ScanResult {
        scan(&[dir.to_path_buf()], rules, &Config::default()).unwrap()
    }

    #[test]
    fn scan_finds_unwrap_violation() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("main.rs"),
            "fn main() {\n    foo().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(result.findings.len(), 1);
        let f = &result.findings[0];
        assert_eq!(f.rule_id, RuleId::from("test-unwrap"));
        assert_eq!(f.severity, Severity::Error);
        assert_eq!(f.line, 2);
        assert!(f.matched_text.contains("unwrap()"));
    }

    #[test]
    fn scan_clean_file_no_findings() {
        let dir = tempdir().unwrap();
        write(dir.path().join("main.rs"), "fn main() { let x = foo(); }\n").unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(result.findings.len(), 0);
        assert_eq!(result.stats.files_scanned, 1);
    }

    #[test]
    fn scan_unsupported_language_ignored() {
        let dir = tempdir().unwrap();
        write(dir.path().join("script.py"), "x.unwrap()\n").unwrap();
        write(dir.path().join("main.rs"), "fn main() {}\n").unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(result.findings.len(), 0);
        assert_eq!(result.stats.files_scanned, 1);
    }

    #[test]
    fn scan_explicit_file_path() {
        let dir = tempdir().unwrap();
        let file = dir.path().join("main.rs");
        write(&file, "fn main() { foo().unwrap(); }\n").unwrap();
        let result = scan(&[file], &[unwrap_rule()], &Config::default()).unwrap();
        assert_eq!(result.findings.len(), 1);
        assert_eq!(result.stats.files_scanned, 1);
    }

    #[test]
    fn rule_ignores_glob_respected() {
        let dir = tempdir().unwrap();
        let tests_dir = dir.path().join("tests");
        create_dir(&tests_dir).unwrap();
        write(
            tests_dir.join("test_main.rs"),
            "fn t() { foo().unwrap(); }\n",
        )
        .unwrap();
        write(
            dir.path().join("main.rs"),
            "fn main() { foo().unwrap(); }\n",
        )
        .unwrap();
        let rule = parse_rule(
            r#"
id: ign
language: rust
severity: error
category: correctness
message: x
rule:
  kind: call_expression
  regex: '\.unwrap\(\)\s*$'
ignores:
  - "**/tests/**"
"#,
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 1);
        assert!(result.findings[0]
            .file
            .to_string_lossy()
            .contains("main.rs"));
    }

    #[test]
    fn config_ignores_respected() {
        let dir = tempdir().unwrap();
        let gen = dir.path().join("generated");
        create_dir(&gen).unwrap();
        write(gen.join("out.rs"), "fn g() { foo().unwrap(); }\n").unwrap();
        write(
            dir.path().join("main.rs"),
            "fn main() { foo().unwrap(); }\n",
        )
        .unwrap();
        let mut cfg = Config::default();
        cfg.scan.ignores = vec!["**/generated/**".to_string()];
        let result = scan(&[dir.path().to_path_buf()], &[unwrap_rule()], &cfg).unwrap();
        assert_eq!(result.stats.files_scanned, 1);
        assert_eq!(result.findings.len(), 1);
    }

    #[test]
    fn config_invalid_glob_is_an_error() {
        let dir = tempdir().unwrap();
        let mut cfg = Config::default();
        cfg.scan.ignores = vec!["[".to_string()];
        let err = scan(&[dir.path().to_path_buf()], &[unwrap_rule()], &cfg).unwrap_err();
        assert!(matches!(err, ScanError::Glob(_)), "{err:?}");
    }

    #[test]
    fn rule_without_kind_fails_to_compile() {
        let dir = tempdir().unwrap();
        let rule = parse_rule(
            r#"
id: no-kind
language: rust
severity: error
category: correctness
message: x
rule:
  regex: 'unwrap'
"#,
        )
        .unwrap();
        let err = scan(&[dir.path().to_path_buf()], &[rule], &Config::default()).unwrap_err();
        assert!(
            matches!(&err, ScanError::RuleCompile { id, .. } if *id == RuleId::from("no-kind")),
            "{err:?}"
        );
    }

    #[test]
    fn stats_counting_accurate() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("a.rs"),
            "fn f() { foo().unwrap(); bar().unwrap(); }\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(result.stats.errors, 2);
        assert_eq!(result.stats.warnings, 0);
        assert_eq!(result.stats.total, 2);
        assert_eq!(result.stats.files_scanned, 1);
    }

    #[test]
    fn scan_empty_file() {
        let dir = tempdir().unwrap();
        write(dir.path().join("empty.rs"), "").unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(result.findings.len(), 0);
        assert_eq!(result.stats.files_scanned, 1);
    }

    #[test]
    fn scan_complex_rule() {
        let rule = parse_rule(
            r#"
id: dbg
language: rust
severity: error
category: security
message: debug on secret
rule:
  kind: attribute_item
  all:
    - regex: 'derive\([^)]*Debug'
    - precedes:
        kind: struct_item
        has:
          kind: field_identifier
          regex: '^(api_key|password|secret)$'
          stopBy: end
"#,
        )
        .unwrap();
        let dir = tempdir().unwrap();
        write(
            dir.path().join("t.rs"),
            "#[derive(Debug)]\nstruct Config {\n    api_key: String,\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 1);
        assert_eq!(result.findings[0].rule_id, RuleId::from("dbg"));
    }

    #[test]
    fn typescript_rule_applies_to_tsx_files() {
        let rule = parse_rule(
            r#"
id: ts-any
language: typescript
severity: warning
category: slop
message: no any
rule:
  kind: predefined_type
  regex: '^any$'
"#,
        )
        .unwrap();
        let dir = tempdir().unwrap();
        write(dir.path().join("a.ts"), "let x: any = 1;\n").unwrap();
        write(dir.path().join("b.tsx"), "let y: any = 2;\n").unwrap();
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.stats.files_scanned, 2);
        assert_eq!(result.stats.warnings, 2);
    }

    #[test]
    fn scan_with_disable_comment_filters_findings() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("main.rs"),
            "fn main() {\n    // slopguard-disable-next-line\n    foo().unwrap();\n    bar().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(
            result.findings.len(),
            1,
            "only the non-disabled unwrap should remain"
        );
        assert_eq!(result.findings[0].line, 4);
    }

    #[test]
    fn scan_with_disable_rule_id_filters_only_that_rule() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("main.rs"),
            "fn main() {\n    // slopguard-disable-next-line test-unwrap\n    foo().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(result.findings.len(), 0);
    }

    fn unwrap_rule_skipping_test_code() -> Rule {
        parse_rule(
            r#"
id: test-unwrap
language: rust
severity: error
category: correctness
message: ".unwrap() forbidden"
rule:
  kind: call_expression
  regex: '\.unwrap\(\)\s*$'
skip_test_code: true
"#,
        )
        .unwrap()
    }

    #[test]
    fn cfg_test_block_excluded_by_post_filter() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("main.rs"),
            "fn prod() {\n    foo().unwrap();\n}\n\n#[cfg(test)]\nmod tests {\n    fn test_it() {\n        bar().unwrap();\n    }\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule_skipping_test_code()]);
        assert_eq!(
            result.findings.len(),
            1,
            "should only find the prod unwrap, not the one inside #[cfg(test)]"
        );
        assert_eq!(result.findings[0].line, 2);
    }

    #[test]
    fn cfg_test_kept_without_skip_test_code() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("main.rs"),
            "fn prod() {\n    foo().unwrap();\n}\n\n#[cfg(test)]\nmod tests {\n    fn test_it() {\n        bar().unwrap();\n    }\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(
            result.findings.len(),
            2,
            "rule without skip_test_code should find both"
        );
    }

    #[test]
    fn integration_test_file_excluded_by_skip_test_code() {
        let dir = tempdir().unwrap();
        let tests_dir = dir.path().join("tests");
        std::fs::create_dir(&tests_dir).unwrap();
        write(
            tests_dir.join("it.rs"),
            "fn check() {\n    foo().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule_skipping_test_code()]);
        assert_eq!(
            result.findings.len(),
            0,
            "unwrap inside a tests/ integration file should be skipped"
        );
    }

    #[test]
    fn integration_test_file_kept_without_skip_test_code() {
        let dir = tempdir().unwrap();
        let tests_dir = dir.path().join("tests");
        std::fs::create_dir(&tests_dir).unwrap();
        write(
            tests_dir.join("it.rs"),
            "fn check() {\n    foo().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(
            result.findings.len(),
            1,
            "rule without skip_test_code should still flag tests/ files"
        );
    }

    #[test]
    fn test_crate_directory_excluded_by_skip_test_code() {
        let dir = tempdir().unwrap();
        let test_crate = dir
            .path()
            .join("crates")
            .join("integrations_tests")
            .join("src");
        std::fs::create_dir_all(&test_crate).unwrap();
        write(
            test_crate.join("api.rs"),
            "fn check() {\n    foo().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule_skipping_test_code()]);
        assert_eq!(
            result.findings.len(),
            0,
            "unwrap inside a *_tests crate should be skipped"
        );
    }

    #[test]
    fn test_crate_directory_kept_without_skip_test_code() {
        let dir = tempdir().unwrap();
        let test_crate = dir
            .path()
            .join("crates")
            .join("integrations_tests")
            .join("src");
        std::fs::create_dir_all(&test_crate).unwrap();
        write(
            test_crate.join("api.rs"),
            "fn check() {\n    foo().unwrap();\n}\n",
        )
        .unwrap();
        let result = scan_dir(dir.path(), &[unwrap_rule()]);
        assert_eq!(
            result.findings.len(),
            1,
            "rule without skip_test_code should still flag *_tests crate files"
        );
    }

    #[test]
    fn all_builtin_rules_compile() {
        let rules = load_builtin_rules().unwrap();
        assert!(
            rules.len() >= 55,
            "expected at least 55 rules, got {}",
            rules.len()
        );
        let compiled = compile_rules(&rules).expect("all builtin rules should compile");
        let ast_rule_count = rules
            .iter()
            .filter(|r| !r.is_metric() && !r.is_cross_file())
            .count();
        assert_eq!(compiled.by_id.len(), ast_rule_count);
        assert!(
            !compiled.cross_file.is_empty(),
            "builtin rules should include cross-file rules"
        );
        assert!(
            !compiled.metrics.is_empty(),
            "builtin rules should include metric rules"
        );
    }

    #[test]
    fn scan_files_only_scans_given_files() {
        let dir = tempdir().unwrap();
        let a = dir.path().join("a.rs");
        let b = dir.path().join("b.rs");
        write(&a, "fn a() {\n    foo().unwrap();\n}\n").unwrap();
        write(&b, "fn b() {\n    bar().unwrap();\n}\n").unwrap();

        let result = scan_files(&[a], &[unwrap_rule()], &Config::default()).unwrap();
        assert_eq!(result.findings.len(), 1);
        assert_eq!(result.stats.files_scanned, 1);
        assert!(result.findings[0].file.to_string_lossy().contains("a.rs"));
    }

    #[test]
    fn scan_files_skips_unsupported_language() {
        let dir = tempdir().unwrap();
        let py = dir.path().join("script.py");
        write(&py, "x.unwrap()\n").unwrap();

        let result = scan_files(&[py], &[unwrap_rule()], &Config::default()).unwrap();
        assert_eq!(result.findings.len(), 0);
        assert_eq!(result.stats.files_scanned, 0);
    }

    #[test]
    fn scan_files_skips_missing_file() {
        let dir = tempdir().unwrap();
        let missing = dir.path().join("gone.rs");

        let result = scan_files(&[missing], &[unwrap_rule()], &Config::default()).unwrap();
        assert_eq!(result.findings.len(), 0);
        assert_eq!(result.stats.files_scanned, 0);
    }

    #[test]
    fn scan_files_respects_config_ignores() {
        let dir = tempdir().unwrap();
        let gen = dir.path().join("generated");
        create_dir(&gen).unwrap();
        let out = gen.join("out.rs");
        write(&out, "fn g() { foo().unwrap(); }\n").unwrap();

        let mut cfg = Config::default();
        cfg.scan.ignores = vec!["**/generated/**".to_string()];
        let result = scan_files(&[out], &[unwrap_rule()], &cfg).unwrap();
        assert_eq!(result.findings.len(), 0);
        assert_eq!(result.stats.files_scanned, 0);
    }

    #[test]
    fn scan_files_cached_keeps_other_entries() {
        let src_dir = tempdir().unwrap();
        let cache_dir = tempdir().unwrap();
        let cache_path = cache_dir.path().join("cache");
        let a = src_dir.path().join("a.rs");
        let b = src_dir.path().join("b.rs");
        write(&a, "fn a() {\n    foo().unwrap();\n}\n").unwrap();
        write(&b, "fn b() {\n    bar().unwrap();\n}\n").unwrap();

        let rules = [unwrap_rule()];
        let config = Config::default();
        let paths = [src_dir.path().to_path_buf()];

        scan_cached(&paths, &rules, &config, &cache_path).unwrap();

        // A partial scan must not evict the entry of the file it skipped.
        scan_files_cached(&[a], &rules, &config, &cache_path).unwrap();

        let result = scan_cached(&paths, &rules, &config, &cache_path).unwrap();
        let stats = result.cache_stats.as_ref().unwrap();
        assert_eq!(stats.cached, 2, "a partial scan must not prune");
        assert_eq!(stats.changed, 0);
    }

    fn metric_rule(body: &str) -> Rule {
        parse_rule(body).unwrap()
    }

    fn file_lines_rule() -> Rule {
        metric_rule(
            r#"
id: test-file-lines
language: rust
severity: warning
category: slop
metric: file_lines
threshold: 10
message: "File is too long"
"#,
        )
    }

    /// `n` lines of trivial Rust, one statement per line.
    fn rust_lines(n: usize) -> String {
        (0..n).map(|i| format!("// line {i}\n")).collect()
    }

    #[test]
    fn scan_finds_file_lines_violation() {
        let dir = tempdir().unwrap();
        write(dir.path().join("big.rs"), rust_lines(12)).unwrap();
        let result = scan_dir(dir.path(), &[file_lines_rule()]);
        assert_eq!(result.findings.len(), 1);
        let f = &result.findings[0];
        assert_eq!(f.rule_id, RuleId::from("test-file-lines"));
        assert_eq!(f.line, 1);
        assert_eq!(f.column, 1);
        assert_eq!(f.end_line, 1);
        assert_eq!(f.end_column, 1);
        assert_eq!(f.matched_text, "12 lines");
    }

    #[test]
    fn metric_message_interpolates_value() {
        let dir = tempdir().unwrap();
        write(dir.path().join("big.rs"), rust_lines(12)).unwrap();
        let rule = metric_rule(
            r#"
id: test-interpolate
language: rust
severity: warning
category: slop
metric: file_lines
threshold: 10
message: "File exceeds 10 lines ($value lines)"
"#,
        );
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 1);
        let message = &result.findings[0].message;
        assert!(message.contains("(12 lines)"), "got: {message}");
        assert!(!message.contains("$value"), "got: {message}");
    }

    #[test]
    fn metric_rule_below_threshold_no_finding() {
        let dir = tempdir().unwrap();
        write(dir.path().join("exact.rs"), rust_lines(10)).unwrap();
        let result = scan_dir(dir.path(), &[file_lines_rule()]);
        assert_eq!(
            result.findings.len(),
            0,
            "a file of exactly the threshold length must not fire"
        );
    }

    #[test]
    fn metric_comment_ratio_finding() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("commented.rs"),
            "// a\n// b\n// c\n// d\nfn f() {}\nfn g() {}\nfn h() {}\n",
        )
        .unwrap();
        let rule = metric_rule(
            r#"
id: test-comment-ratio
language: rust
severity: warning
category: slop
metric: comment_ratio
threshold: 0.4
message: "Too many comments ($value)"
"#,
        );
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 1);
        assert!(
            result.findings[0].matched_text.ends_with("comment ratio"),
            "got: {}",
            result.findings[0].matched_text
        );
    }

    #[test]
    fn metric_rule_respects_ignores_glob() {
        let dir = tempdir().unwrap();
        let gen = dir.path().join("generated");
        create_dir(&gen).unwrap();
        write(gen.join("out.rs"), rust_lines(12)).unwrap();
        write(dir.path().join("main.rs"), rust_lines(12)).unwrap();
        let rule = metric_rule(
            r#"
id: test-metric-ignores
language: rust
severity: warning
category: slop
metric: file_lines
threshold: 10
message: "too long"
ignores:
  - "**/generated/**"
"#,
        );
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 1);
        assert!(result.findings[0]
            .file
            .to_string_lossy()
            .contains("main.rs"));
    }

    #[test]
    fn metric_rule_respects_files_glob() {
        let dir = tempdir().unwrap();
        let src = dir.path().join("src");
        create_dir(&src).unwrap();
        write(src.join("lib.rs"), rust_lines(12)).unwrap();
        write(dir.path().join("build.rs"), rust_lines(12)).unwrap();
        let rule = metric_rule(
            r#"
id: test-metric-files
language: rust
severity: warning
category: slop
metric: file_lines
threshold: 10
message: "too long"
files:
  - "**/src/**/*.rs"
"#,
        );
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 1);
        assert!(result.findings[0].file.to_string_lossy().contains("lib.rs"));
    }

    #[test]
    fn metric_rule_skip_test_code_skips_test_files() {
        let dir = tempdir().unwrap();
        let tests_dir = dir.path().join("tests");
        create_dir(&tests_dir).unwrap();
        write(tests_dir.join("it.rs"), rust_lines(12)).unwrap();

        let skipping = metric_rule(
            r#"
id: test-metric-skip
language: rust
severity: warning
category: slop
metric: file_lines
threshold: 10
message: "too long"
skip_test_code: true
"#,
        );
        let skipped = scan_dir(dir.path(), &[skipping]);
        assert_eq!(skipped.findings.len(), 0);
        let reported = scan_dir(dir.path(), &[file_lines_rule()]);
        assert_eq!(reported.findings.len(), 1);
    }

    #[test]
    fn metric_only_ruleset_still_scans() {
        let dir = tempdir().unwrap();
        write(dir.path().join("big.rs"), rust_lines(12)).unwrap();
        let result = scan_dir(dir.path(), &[file_lines_rule()]);
        assert_eq!(
            result.findings.len(),
            1,
            "a rule set with only metric rules must still scan files"
        );
    }

    #[test]
    fn metric_and_ast_rules_together() {
        let dir = tempdir().unwrap();
        let mut source = String::from("fn main() {\n    foo().unwrap();\n}\n");
        source.push_str(&rust_lines(12));
        write(dir.path().join("main.rs"), source).unwrap();

        let result = scan_dir(dir.path(), &[unwrap_rule(), file_lines_rule()]);
        assert_eq!(result.findings.len(), 2);
        let first = &result.findings[0];
        assert_eq!(first.rule_id, RuleId::from("test-file-lines"));
        assert_eq!(first.line, 1);
        let second = &result.findings[1];
        assert_eq!(second.rule_id, RuleId::from("test-unwrap"));
    }

    #[test]
    fn metric_rule_wrong_language_not_applied() {
        let dir = tempdir().unwrap();
        write(dir.path().join("big.rs"), rust_lines(12)).unwrap();
        let rule = metric_rule(
            r#"
id: test-metric-ts
language: typescript
severity: warning
category: slop
metric: file_lines
threshold: 10
message: "too long"
"#,
        );
        let result = scan_dir(dir.path(), &[rule]);
        assert_eq!(result.findings.len(), 0);
    }

    #[test]
    fn metric_findings_are_cached() {
        let src_dir = tempdir().unwrap();
        let cache_dir = tempdir().unwrap();
        let cache_path = cache_dir.path().join("cache");
        write(src_dir.path().join("big.rs"), rust_lines(12)).unwrap();

        let rules = [file_lines_rule()];
        let config = Config::default();
        let paths = [src_dir.path().to_path_buf()];

        let first = scan_cached(&paths, &rules, &config, &cache_path).unwrap();
        assert_eq!(first.findings.len(), 1);
        assert_eq!(first.cache_stats.as_ref().unwrap().changed, 1);

        let second = scan_cached(&paths, &rules, &config, &cache_path).unwrap();
        assert_eq!(second.cache_stats.as_ref().unwrap().cached, 1);
        assert_eq!(second.findings.len(), 1);
        assert_eq!(second.findings[0].matched_text, "12 lines");
    }

    #[test]
    fn scan_with_cache() {
        let src_dir = tempdir().unwrap();
        let cache_dir = tempdir().unwrap();
        let cache_path = cache_dir.path().join("cache");
        write(
            src_dir.path().join("main.rs"),
            "fn main() {\n    foo().unwrap();\n}\n",
        )
        .unwrap();

        let rules = [unwrap_rule()];
        let config = Config::default();

        let result1 = scan_cached(
            &[src_dir.path().to_path_buf()],
            &rules,
            &config,
            &cache_path,
        )
        .unwrap();

        assert_eq!(result1.findings.len(), 1);
        let cache_stats1 = result1.cache_stats.as_ref().unwrap();
        assert_eq!(cache_stats1.cached, 0, "first scan: nothing cached");
        assert_eq!(cache_stats1.changed, 1, "first scan: one file scanned");

        let result2 = scan_cached(
            &[src_dir.path().to_path_buf()],
            &rules,
            &config,
            &cache_path,
        )
        .unwrap();

        assert_eq!(result2.findings.len(), 1);
        let cache_stats2 = result2.cache_stats.as_ref().unwrap();
        assert_eq!(cache_stats2.cached, 1, "second scan: one file from cache");
        assert_eq!(cache_stats2.changed, 0, "second scan: nothing changed");
    }

    fn single_impl_trait_rule() -> Rule {
        parse_rule(
            r#"
id: no-single-impl-trait
language: rust
severity: warning
category: slop
cross_file: single_impl_trait
message: "Trait with a single implementation in the project."
skip_test_code: true
"#,
        )
        .unwrap()
    }

    #[test]
    fn cross_file_single_impl_trait_reported() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("repo.rs"),
            "pub trait Repository {\n    fn get(&self);\n}\n",
        )
        .unwrap();
        write(
            dir.path().join("pg.rs"),
            "pub struct Pg;\n\nimpl Repository for Pg {\n    fn get(&self) {}\n}\n",
        )
        .unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(result.findings.len(), 1);
        let f = &result.findings[0];
        assert_eq!(f.rule_id, RuleId::from("no-single-impl-trait"));
        assert!(f.file.to_string_lossy().ends_with("repo.rs"));
        assert_eq!(f.line, 1);
        assert_eq!(f.matched_text, "pub trait Repository");
    }

    #[test]
    fn cross_file_two_impls_not_reported() {
        let dir = tempdir().unwrap();
        write(dir.path().join("repo.rs"), "pub trait Repository {}\n").unwrap();
        write(dir.path().join("pg.rs"), "impl Repository for Pg {}\n").unwrap();
        write(dir.path().join("mem.rs"), "impl Repository for Mem {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(result.findings.len(), 0);
    }

    #[test]
    fn cross_file_no_impl_not_reported() {
        let dir = tempdir().unwrap();
        write(dir.path().join("repo.rs"), "pub trait Repository {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(result.findings.len(), 0);
    }

    #[test]
    fn cross_file_blanket_impl_not_reported() {
        let dir = tempdir().unwrap();
        write(dir.path().join("desc.rs"), "pub trait Describe {}\n").unwrap();
        write(dir.path().join("all.rs"), "impl<T> Describe for T {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(result.findings.len(), 0);
    }

    #[test]
    fn cross_file_duplicate_trait_name_not_reported() {
        let dir = tempdir().unwrap();
        write(dir.path().join("a.rs"), "pub trait Repository {}\n").unwrap();
        write(dir.path().join("b.rs"), "pub trait Repository {}\n").unwrap();
        write(dir.path().join("pg.rs"), "impl Repository for Pg {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(result.findings.len(), 0);
    }

    #[test]
    fn cross_file_disable_comment_on_declaration() {
        let dir = tempdir().unwrap();
        write(
            dir.path().join("repo.rs"),
            "// slopguard-disable-next-line no-single-impl-trait\npub trait Repository {}\n",
        )
        .unwrap();
        write(dir.path().join("pg.rs"), "impl Repository for Pg {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(
            result.findings.len(),
            0,
            "a disable comment above the declaration must suppress the finding"
        );
    }

    #[test]
    fn cross_file_cfg_test_mock_counts_as_second_impl() {
        let dir = tempdir().unwrap();
        write(dir.path().join("repo.rs"), "pub trait Repository {}\n").unwrap();
        write(dir.path().join("pg.rs"), "impl Repository for Pg {}\n").unwrap();
        write(
            dir.path().join("mock.rs"),
            "#[cfg(test)]\nmod tests {\n    struct MockRepo;\n    impl Repository for MockRepo {}\n}\n",
        )
        .unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(
            result.findings.len(),
            0,
            "a test mock counts as a second implementation"
        );
    }

    #[test]
    fn cross_file_declaration_in_test_path_not_reported() {
        let dir = tempdir().unwrap();
        let tests_dir = dir.path().join("tests");
        create_dir(&tests_dir).unwrap();
        write(tests_dir.join("support.rs"), "pub trait Repository {}\n").unwrap();
        write(tests_dir.join("pg.rs"), "impl Repository for Pg {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(result.findings.len(), 0);
    }

    #[test]
    fn cross_file_not_run_for_scan_files() {
        let dir = tempdir().unwrap();
        let repo = dir.path().join("repo.rs");
        let pg = dir.path().join("pg.rs");
        write(&repo, "pub trait Repository {}\n").unwrap();
        write(&pg, "impl Repository for Pg {}\n").unwrap();

        let rules = [single_impl_trait_rule()];
        let partial = scan_files(&[repo, pg], &rules, &Config::default()).unwrap();
        assert_eq!(
            partial.findings.len(),
            0,
            "an explicit file list has an incomplete project index"
        );

        let full = scan_dir(dir.path(), &rules);
        assert_eq!(full.findings.len(), 1);
    }

    #[test]
    fn cross_file_survives_cache_round_trip() {
        let src_dir = tempdir().unwrap();
        let cache_dir = tempdir().unwrap();
        let cache_path = cache_dir.path().join("cache");
        write(src_dir.path().join("repo.rs"), "pub trait Repository {}\n").unwrap();
        write(src_dir.path().join("pg.rs"), "impl Repository for Pg {}\n").unwrap();

        let rules = [single_impl_trait_rule()];
        let config = Config::default();
        let paths = [src_dir.path().to_path_buf()];

        let first = scan_cached(&paths, &rules, &config, &cache_path).unwrap();
        assert_eq!(first.findings.len(), 1);
        assert_eq!(first.cache_stats.as_ref().unwrap().changed, 2);

        let second = scan_cached(&paths, &rules, &config, &cache_path).unwrap();
        let stats = second.cache_stats.as_ref().unwrap();
        assert_eq!(stats.cached, 2, "both files should come from the cache");
        assert_eq!(stats.changed, 0);
        assert_eq!(
            second.findings.len(),
            1,
            "symbols must survive the cache round trip"
        );
    }

    #[test]
    fn cross_file_rule_with_no_ast_rules_still_parses_files() {
        let dir = tempdir().unwrap();
        write(dir.path().join("repo.rs"), "pub trait Repository {}\n").unwrap();
        write(dir.path().join("pg.rs"), "impl Repository for Pg {}\n").unwrap();

        let result = scan_dir(dir.path(), &[single_impl_trait_rule()]);
        assert_eq!(
            result.findings.len(),
            1,
            "a cross-file-only ruleset must still parse every file"
        );
    }
}