deps-core 0.11.0

//! Shared LSP response builders.

use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use tower_lsp_server::ls_types::{Position, Range, TextEdit, Uri};

use crate::osv::VulnerabilityMap;
use crate::{Dependency, InvalidPackageName, PackageName, VersionReq};

mod code_actions;
mod code_lenses;
mod diagnostics;
mod hover;
mod inlay_hints;
#[cfg(test)]
mod test_support;

pub use code_actions::generate_code_actions;
pub use code_lenses::{collect_update_all_edits, generate_code_lenses};
pub use diagnostics::{
    DiagnosticSeverities, UNSATISFIABLE_DIAGNOSTIC_CODE, compile_requirement_unless,
    generate_diagnostics, generate_diagnostics_from_cache, requirement_is_unsatisfiable,
};
pub use hover::generate_hover;
pub use inlay_hints::generate_inlay_hints;

/// Maximum number of recent versions hover's "Recent versions" section renders.
///
/// Also the walk target for registries (NuGet, npm) that must fetch publish times for
/// only the versions actually rendered, rather than the entire version history.
pub const HOVER_RECENT_VERSIONS: usize = 8;

/// Registry version data for one package, fetched together in a single round trip.
///
/// `latest` and `available` are deliberately asymmetric — this is load-bearing, not an
/// oversight:
/// - `latest` comes from this ecosystem's own `Registry::select_latest_matching(.., "*")`
///   pick, which excludes yanked (and, for semver/node-semver `*`, prerelease) versions —
///   the same value `get_latest_matching` returned before this type existed.
/// - `available` is the **unfiltered** `get_versions` output: every published version,
///   newest-first, yanked and prerelease entries included.
///
/// The unsatisfiable-requirement check (see `crate::lsp_helpers::requirement_is_unsatisfiable`)
/// scans `available` and deliberately does not filter it: a requirement that only matches a
/// yanked or prerelease version is still satisfied, so filtering `available` the same way
/// `latest` is filtered would produce false "no published version satisfies" warnings.
///
/// `yanked` is the subset of `available` (same version-string encoding) that the registry
/// reported as yanked/deprecated. It exists because `Registry::get_latest_matching` — the
/// call that used to populate this cache — filters yanked entries out by contract on every
/// current registry implementation, so a per-version yanked flag threaded through *that*
/// call would always read `false` (see #233). `available` now comes from the unfiltered
/// `get_versions` instead, which does observe yanked entries, so `yanked` is derived from
/// that same fetch rather than discarded.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PackageVersions {
    /// Latest usable version for this package.
    pub latest: String,
    /// Every published version, newest-first, unfiltered.
    pub available: Arc<[String]>,
    /// Subset of `available` reported as yanked/deprecated by the registry.
    pub yanked: Arc<[String]>,
    /// When `latest` was published, if the registry exposes it. `None` when
    /// the ecosystem doesn't wire [`crate::Version::published_at`] or the fetch
    /// never ran.
    ///
    /// Deliberately a field on this single per-package struct rather than a
    /// second parallel map keyed alongside `latest` — the earlier two-map
    /// design (issue #227 critique C3) let `latest` and its age drift apart
    /// silently whenever one map was updated (e.g. lockfile-resolved
    /// overwrite) without the other. Bundling them here makes that
    /// desync impossible: whoever sets `latest` sets `published_at` too.
    pub published_at: Option<crate::freshness::PublishTime>,
}

impl PackageVersions {
    /// Builds a `PackageVersions` from only the "latest" version string, with `available`
    /// populated as the single-element list `[latest]`.
    ///
    /// **Test-only in intent.** The one-element `available` this produces is a real, if
    /// small, version list — it is not "empty/unknown", so `requirement_is_unsatisfiable`
    /// will evaluate a requirement against it. Do **not** use this for a lock-file-only
    /// population path that has no real version list to offer (use
    /// [`latest_without_list`](Self::latest_without_list) there instead, which leaves
    /// `available` genuinely empty) — that exact substitution is the false-positive N5 was
    /// written to prevent: it would let the unsatisfiable-requirement check produce a
    /// verdict against a fabricated one-entry list before any registry fetch has run. Real
    /// registry fetches always populate `available` from the full `get_versions` result
    /// instead of using either constructor.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::PackageVersions;
    ///
    /// let versions = PackageVersions::latest_only("1.0.214");
    /// assert_eq!(versions.latest, "1.0.214");
    /// assert_eq!(&*versions.available, &["1.0.214".to_string()]);
    /// ```
    pub fn latest_only(latest: impl Into<String>) -> Self {
        let latest = latest.into();
        let available = Arc::from(vec![latest.clone()]);
        Self {
            latest,
            available,
            yanked: Arc::from(Vec::new()),
            published_at: None,
        }
    }

    /// Builds a `PackageVersions` with no version list — used where only the "latest" value
    /// is known and probing further would be misleading, notably the lock-file population
    /// path (`crates/deps-lsp/src/document/lifecycle.rs`), which must not populate a
    /// plausible-looking one-element `available` list before any registry fetch has run: the
    /// unsatisfiable-requirement check treats an empty `available` as "still loading, skip".
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::PackageVersions;
    ///
    /// let versions = PackageVersions::latest_without_list("1.0.195");
    /// assert_eq!(versions.latest, "1.0.195");
    /// assert!(versions.available.is_empty());
    /// ```
    pub fn latest_without_list(latest: impl Into<String>) -> Self {
        Self {
            latest: latest.into(),
            available: Arc::from(Vec::new()),
            yanked: Arc::from(Vec::new()),
            published_at: None,
        }
    }
}

/// Bundles the two per-package version maps (`cached`, `resolved`) that LSP handlers pass
/// together everywhere.
///
/// Grouping them prevents accidentally swapping the two map arguments at a call site, since
/// the compiler can no longer typecheck them positionally.
///
/// # Examples
///
/// ```
/// use deps_core::{PackageName, PackageVersions, VersionData};
/// use std::collections::HashMap;
///
/// let mut cached = HashMap::new();
/// cached.insert(PackageName::new("serde"), PackageVersions::latest_only("1.0.214"));
///
/// let mut resolved = HashMap::new();
/// resolved.insert(PackageName::new("serde"), "1.0.200".to_string());
///
/// let versions = VersionData::new(&cached, &resolved);
///
/// assert_eq!(versions.cached.get("serde").map(|v| v.latest.as_str()), Some("1.0.214"));
/// assert_eq!(versions.resolved.get("serde"), Some(&"1.0.200".to_string()));
/// ```
#[derive(Debug, Clone, Copy)]
pub struct VersionData<'a> {
    /// Latest known versions and full version lists from the registry, keyed by package name.
    pub cached: &'a HashMap<PackageName, PackageVersions>,
    /// Versions actually resolved in the lock file, keyed by package name.
    pub resolved: &'a HashMap<PackageName, String>,
    /// OSV scan results, keyed by normalized package name. `None` when no
    /// scan has run yet (e.g. the feature is disabled) — distinct from an
    /// empty map, which would mean "scanned, nothing found".
    pub vulnerabilities: Option<&'a VulnerabilityMap>,
    /// Yanked-version findings, keyed by normalized package name -> the
    /// version string found yanked (the in-use version, or `latest` when
    /// only `latest` itself is yanked — see `deps-lsp`'s lifecycle probe).
    /// `None` when no yanked check has run yet — distinct from an empty map,
    /// which would mean "checked, nothing yanked".
    pub yanked: Option<&'a HashMap<String, String>>,
    /// Packages whose registry fetch errored or timed out during the most
    /// recent lifecycle fetch, keyed by normalized package name. Lets
    /// [`generate_diagnostics_from_cache`] distinguish "the registry was
    /// asked and said this package doesn't exist" from "the registry
    /// couldn't be asked" (#267) — a `cached` miss alone conflates both into
    /// a misleading "Unknown package" diagnostic. `None` when no fetch has
    /// run yet, same convention as [`Self::yanked`].
    pub fetch_failed: Option<&'a HashSet<String>>,
}

impl<'a> VersionData<'a> {
    /// Creates a new `VersionData` from the cached and resolved version maps.
    ///
    /// `vulnerabilities` starts `None`; chain [`Self::with_vulnerabilities`]
    /// to attach a scan result.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::VersionData;
    /// use std::collections::HashMap;
    ///
    /// let cached = HashMap::new();
    /// let resolved = HashMap::new();
    /// let versions = VersionData::new(&cached, &resolved);
    /// assert!(versions.cached.is_empty());
    /// assert!(versions.vulnerabilities.is_none());
    /// ```
    pub fn new(
        cached: &'a HashMap<PackageName, PackageVersions>,
        resolved: &'a HashMap<PackageName, String>,
    ) -> Self {
        Self {
            cached,
            resolved,
            vulnerabilities: None,
            yanked: None,
            fetch_failed: None,
        }
    }

    /// Attaches an OSV scan result to this `VersionData`.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::VersionData;
    /// use deps_core::osv::VulnerabilityMap;
    /// use std::collections::HashMap;
    ///
    /// let cached = HashMap::new();
    /// let resolved = HashMap::new();
    /// let vulns = VulnerabilityMap::new();
    /// let versions = VersionData::new(&cached, &resolved).with_vulnerabilities(&vulns);
    /// assert!(versions.vulnerabilities.is_some());
    /// ```
    #[must_use]
    pub fn with_vulnerabilities(mut self, vulnerabilities: &'a VulnerabilityMap) -> Self {
        self.vulnerabilities = Some(vulnerabilities);
        self
    }

    /// Attaches yanked-version findings to this `VersionData`.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::VersionData;
    /// use std::collections::HashMap;
    ///
    /// let cached = HashMap::new();
    /// let resolved = HashMap::new();
    /// let yanked = HashMap::new();
    /// let versions = VersionData::new(&cached, &resolved).with_yanked(&yanked);
    /// assert!(versions.yanked.is_some());
    /// ```
    #[must_use]
    pub fn with_yanked(mut self, yanked: &'a HashMap<String, String>) -> Self {
        self.yanked = Some(yanked);
        self
    }

    /// Attaches the set of packages whose registry fetch failed (error or timeout)
    /// during the most recent lifecycle fetch.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::VersionData;
    /// use std::collections::{HashMap, HashSet};
    ///
    /// let cached = HashMap::new();
    /// let resolved = HashMap::new();
    /// let fetch_failed = HashSet::new();
    /// let versions = VersionData::new(&cached, &resolved).with_fetch_failed(&fetch_failed);
    /// assert!(versions.fetch_failed.is_some());
    /// ```
    #[must_use]
    pub fn with_fetch_failed(mut self, fetch_failed: &'a HashSet<String>) -> Self {
        self.fetch_failed = Some(fetch_failed);
        self
    }
}

/// Checks whether a cursor position falls within an LSP range (inclusive on both ends).
pub fn position_in_range(pos: Position, range: Range) -> bool {
    if pos.line < range.start.line || pos.line > range.end.line {
        return false;
    }
    if pos.line == range.start.line && pos.character < range.start.character {
        return false;
    }
    if pos.line == range.end.line && pos.character > range.end.character {
        return false;
    }
    true
}

/// Converts byte offsets in source text to LSP `Position` values.
///
/// Precomputes line-start byte offsets once, then maps any byte offset to a
/// `(line, character)` position. Characters are counted as UTF-16 code units
/// as required by the LSP specification.
pub struct LineOffsetTable {
    line_starts: Vec<usize>,
}

impl LineOffsetTable {
    /// Builds the table for `content`.
    pub fn new(content: &str) -> Self {
        let mut line_starts = vec![0];
        for (i, c) in content.char_indices() {
            if c == '\n' {
                line_starts.push(i + 1);
            }
        }
        Self { line_starts }
    }

    /// Absolute byte offset where `line` (0-indexed) starts, or `None` if
    /// `line` is out of range.
    ///
    /// Prefer this over re-deriving a line's start via cursor arithmetic
    /// (`cursor += line.len() + 1`): `str::lines()` strips a trailing `\r`,
    /// so that approach under-counts by one byte per CRLF line and corrupts
    /// every subsequent offset in the file. This table is built by scanning
    /// `char_indices()` for `\n` (see [`new`](Self::new)), which counts the
    /// `\r`, so it stays correct for LF, CRLF and mixed line endings alike.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::LineOffsetTable;
    ///
    /// let table = LineOffsetTable::new("a\r\nb\r\nc");
    /// assert_eq!(table.line_start(0), Some(0));
    /// assert_eq!(table.line_start(1), Some(3));
    /// assert_eq!(table.line_start(2), Some(6));
    /// assert_eq!(table.line_start(3), None);
    /// ```
    pub fn line_start(&self, line: usize) -> Option<usize> {
        self.line_starts.get(line).copied()
    }

    /// Converts a byte offset into an LSP `Position`.
    pub fn byte_offset_to_position(&self, content: &str, offset: usize) -> Position {
        let offset = offset.min(content.len());
        // `offset` is not always a toml-span offset (boundary-safe by
        // construction) — the requirements.txt line parser derives offsets
        // via hand-rolled byte arithmetic, which can land inside a
        // multi-byte character (e.g. a non-ASCII comment or marker string
        // combined with an off-by-a-byte cut). Clamp down to the nearest
        // char boundary rather than panicking on the slice below.
        let mut offset = offset;
        while offset > 0 && !content.is_char_boundary(offset) {
            offset -= 1;
        }
        let line = self
            .line_starts
            .partition_point(|&start| start <= offset)
            .saturating_sub(1);
        let line_start = self.line_starts[line];
        let character = content[line_start..offset]
            .chars()
            .map(|c| c.len_utf16() as u32)
            .sum();
        Position::new(line as u32, character)
    }

    /// Converts an LSP `Position` back into a byte offset — the inverse of
    /// [`byte_offset_to_position`](Self::byte_offset_to_position). Out-of-range lines or
    /// UTF-16 characters clamp to `content.len()` rather than panicking, matching the
    /// forward conversion's `.min(content.len())` guard.
    pub fn position_to_byte_offset(&self, content: &str, position: Position) -> usize {
        let Some(&line_start) = self.line_starts.get(position.line as usize) else {
            return content.len();
        };
        let line_end = self
            .line_starts
            .get(position.line as usize + 1)
            .copied()
            .unwrap_or(content.len());
        let line = &content[line_start..line_end];
        crate::completion::utf16_to_byte_offset(line, position.character)
            .map_or(line_end, |offset| line_start + offset)
            .min(content.len())
    }
}

/// Escapes Markdown syntax characters so untrusted text cannot break out of the
/// Markdown structure it is embedded in.
///
/// Applied to manifest-controlled text (dependency names) before it is written into
/// hover markdown link labels, and to registry-controlled completion metadata
/// (package name/version, description, repository/documentation URLs) before it is
/// written into completion-item link labels and link destinations. Every ASCII
/// punctuation character is backslash-escaped (CommonMark's full escapable set — not
/// just brackets/parens, which would still leave e.g. `<https://evil.example>`
/// autolinks live), and control characters (including newlines) are replaced with a
/// space so the text cannot terminate the single-line block it is embedded in and
/// splice in new content.
///
/// Backslash-escaping is valid in link destinations as well as regular text, so this
/// also neutralizes `)`/`]` breakout attempts in a `[label](destination)` URL. It does
/// *not* block dangerous URI schemes (e.g. `javascript:`) in a destination — that is a
/// separate concern from breaking out of the surrounding Markdown structure.
///
/// Backslash-escaping does *not* work inside inline code spans (CommonMark §6.1) —
/// use [`markdown_code_span`] for text embedded in `` `...` `` instead.
///
/// # Examples
///
/// ```
/// use deps_core::lsp_helpers::escape_markdown;
///
/// assert_eq!(escape_markdown("pkg](evil)[pkg"), r"pkg\]\(evil\)\[pkg");
/// assert_eq!(escape_markdown("a\nb"), "a b");
/// ```
pub fn escape_markdown(s: &str) -> String {
    let mut escaped = String::with_capacity(s.len());
    for c in s.chars() {
        if c.is_control() {
            escaped.push(' ');
            continue;
        }
        if c.is_ascii_punctuation() {
            escaped.push('\\');
        }
        escaped.push(c);
    }
    escaped
}

/// Wraps `content` in a Markdown inline code span (backticks included) that safely
/// contains arbitrary untrusted text, regardless of embedded backticks.
///
/// Backslash-escaping does not work inside code spans (CommonMark §6.1), so instead
/// this fences with one more backtick than the longest run found in `content`, and
/// pads with a single space on each side when `content` starts or ends with a
/// backtick or space (required by CommonMark to keep the fence unambiguous). Control
/// characters (including newlines) are replaced with a space first, since the raw
/// hover string is otherwise free to merge into an adjacent Markdown block.
///
/// # Examples
///
/// ```
/// use deps_core::lsp_helpers::markdown_code_span;
///
/// assert_eq!(markdown_code_span("1.0.0"), "`1.0.0`");
/// assert_eq!(markdown_code_span("a`b"), "``a`b``");
/// ```
pub fn markdown_code_span(content: &str) -> String {
    let sanitized: String = content
        .chars()
        .map(|c| if c.is_control() { ' ' } else { c })
        .collect();

    let max_backtick_run = sanitized
        .split(|c| c != '`')
        .map(str::len)
        .max()
        .unwrap_or(0);
    let fence = "`".repeat(max_backtick_run + 1);

    if sanitized.is_empty() {
        format!("{fence} {fence}")
    } else if sanitized.starts_with(['`', ' ']) || sanitized.ends_with(['`', ' ']) {
        format!("{fence} {sanitized} {fence}")
    } else {
        format!("{fence}{sanitized}{fence}")
    }
}

/// Checks if two version strings have the same major and minor version.
pub fn is_same_major_minor(v1: &str, v2: &str) -> bool {
    if v1.is_empty() || v2.is_empty() {
        return false;
    }

    let mut parts1 = v1.split('.');
    let mut parts2 = v2.split('.');

    if parts1.next() != parts2.next() {
        return false;
    }

    match (parts1.next(), parts2.next()) {
        (Some(m1), Some(m2)) => m1 == m2,
        _ => true,
    }
}

/// Result of checking whether a dependency's declared requirement is already satisfied by
/// the latest known version.
///
/// Diagnostics and inlay hints read this result differently: diagnostics only need to know
/// whether it is safe to skip the "Newer version available" warning, so both `UpToDate` and
/// `Unresolved` suppress it. Inlay hints additionally need to distinguish `Unresolved` from
/// `UpToDate`, since an unresolved requirement (e.g. a dangling Gradle version-catalog
/// `version.ref` alias, or an unexpanded Maven `${property}`) must not render an "up to
/// date" badge that was never actually verified.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum RequirementStatus {
    /// The latest version satisfies the declared requirement.
    UpToDate,
    /// The latest version does not satisfy the declared requirement — a newer version is
    /// available.
    Outdated,
    /// The requirement could not be resolved to a concrete constraint, so no comparison
    /// could be made.
    Unresolved,
}

/// A `requirement` compiled by one ecosystem, ready to test candidate versions against.
///
/// Produced by [`EcosystemFormatter::compile_requirement`]. Kept as a separate object
/// (rather than a single "does any version match" function) so the requirement is parsed
/// once per dependency, and so the scanning loop — including the empty-list guard, the
/// early-exit on first match, and the "skip an unparseable candidate" rule — lives once in
/// [`requirement_is_unsatisfiable`] instead of being reimplemented by all eleven ecosystems.
///
/// # Examples
///
/// ```
/// use deps_core::lsp_helpers::RequirementMatcher;
///
/// struct ExactMatch(String);
///
/// impl RequirementMatcher for ExactMatch {
///     fn matches(&self, version: &str) -> Option<bool> {
///         Some(version == self.0)
///     }
/// }
///
/// let matcher = ExactMatch("1.0.0".to_string());
/// assert_eq!(matcher.matches("1.0.0"), Some(true));
/// assert_eq!(matcher.matches("2.0.0"), Some(false));
/// ```
pub trait RequirementMatcher: Send + Sync {
    /// Tests one candidate version string against the compiled requirement.
    ///
    /// `Some(true)` / `Some(false)`: this candidate provably does / does not satisfy the
    /// requirement. `None`: this candidate *string* could not be parsed by this ecosystem's
    /// version format (e.g. a PyPI legacy release identifier, a Maven timestamped snapshot
    /// qualifier) — the caller skips it and keeps scanning the rest of the list. Never
    /// return `None` to mean "the requirement itself is unusable"; that is
    /// [`EcosystemFormatter::compile_requirement`]'s job, via returning `None` from that
    /// method instead of constructing a matcher at all.
    fn matches(&self, version: &str) -> Option<bool>;
}

/// Ecosystem-specific formatting and comparison logic.
pub trait EcosystemFormatter: Send + Sync {
    /// Normalize package name for lookup (default: identity).
    fn normalize_package_name(&self, name: &PackageName) -> String {
        name.to_string()
    }

    /// Lints `name` against ecosystem-specific naming rules.
    ///
    /// Default: permissive, always `Ok(())`. This is a diagnostic lint, not a
    /// construction-time gate — [`PackageName::new`](crate::PackageName::new)
    /// stays infallible regardless of what this returns. Override only to warn
    /// on names an ecosystem's own tooling would never accept; err on the side
    /// of accepting anything ambiguous, since a false positive here is a
    /// warning on a manifest the user's actual package manager treats as fine.
    ///
    /// # Errors
    ///
    /// Returns [`InvalidPackageName`] carrying the reason `name` fails this
    /// ecosystem's naming rules. The default implementation never errs.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::PackageName;
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    ///
    /// struct PermissiveFormatter;
    ///
    /// impl EcosystemFormatter for PermissiveFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         format!("https://example.com/{name}")
    ///     }
    /// }
    ///
    /// // The default is permissive: any name, including one that would fail an
    /// // ecosystem-specific override, is accepted.
    /// assert!(PermissiveFormatter.validate_package_name("../not/a/real/rule").is_ok());
    /// ```
    fn validate_package_name(&self, _name: &str) -> Result<(), InvalidPackageName> {
        Ok(())
    }

    /// Format version string for code action text edit.
    fn format_version_for_text_edit(&self, version: &str) -> String;

    /// Format `version` as a replacement for the existing requirement text
    /// `current`, preserving `current`'s operator/pin style where the
    /// ecosystem supports more than one.
    ///
    /// Default: ignores `current`, delegating to
    /// [`format_version_for_text_edit`](Self::format_version_for_text_edit).
    /// Override when a bare `format_version_for_text_edit` replacement would
    /// silently change the requirement's semantics — e.g. PyPI's `==1.0.1`
    /// pin becoming `>=1.0.1,<2` on "update version" would defeat the point
    /// of pinning.
    fn format_version_replacing(&self, version: &str, _current: &str) -> String {
        self.format_version_for_text_edit(version)
    }

    /// Check if a version satisfies a requirement string.
    ///
    /// General constraint check (e.g. for completion/candidate filtering) — not the
    /// "is this dependency up to date" hook. That is `is_requirement_up_to_date` below,
    /// which has its own default and its own override points; an ecosystem whose bare
    /// requirement is a floor rather than an auto-following range (see `deps-nuget`)
    /// overrides that method, not this one.
    fn version_satisfies_requirement(&self, version: &str, requirement: &str) -> bool {
        // Handle caret (^) - allows changes that don't modify left-most non-zero
        // ^2.0 allows 2.x.x, ^0.2 allows 0.2.x, ^0.0.3 allows only 0.0.3
        if let Some(req) = requirement.strip_prefix('^') {
            let req_parts: Vec<&str> = req.split('.').collect();
            let ver_parts: Vec<&str> = version.split('.').collect();

            // Must have same major version
            if req_parts.first() != ver_parts.first() {
                return false;
            }

            // For ^X.Y where X > 0, any X.*.* is allowed
            if req_parts.first().is_some_and(|m| *m != "0") {
                return true;
            }

            // For ^0.Y, must have same minor
            if req_parts.len() >= 2 && ver_parts.len() >= 2 {
                return req_parts[1] == ver_parts[1];
            }

            return true;
        }

        // Handle tilde (~) - allows patch-level changes
        // ~2.0 allows 2.0.x, ~2.0.1 allows 2.0.x where x >= 1
        if let Some(req) = requirement.strip_prefix('~') {
            return is_same_major_minor(req, version);
        }

        // Plain version or partial version
        let req_parts: Vec<&str> = requirement.split('.').collect();
        let is_partial_version = req_parts.len() <= 2;

        version == requirement
            || (is_partial_version && is_same_major_minor(requirement, version))
            || (is_partial_version && version.starts_with(requirement))
    }

    /// Whether an unresolved dependency (no lock-file version) should be reported as
    /// up to date against `latest`, given its declared `requirement`.
    ///
    /// Default: `latest` satisfies `requirement` — correct for range-based ecosystems
    /// (Cargo's `^1.2`, npm's `~1.2`, ...) where the declared requirement already
    /// expresses forward compatibility, so a `latest` it accepts is not "newer" in any
    /// actionable sense. Ecosystems where a bare requirement is a minimum floor rather
    /// than an auto-following range (NuGet's bare `Version="1.0.0"`) must override this,
    /// since "does the floor accept `latest`" and "is the pin already `latest`" are
    /// different questions there.
    fn is_requirement_up_to_date(&self, requirement: &VersionReq, latest: &str) -> bool {
        self.version_satisfies_requirement(latest, requirement.as_str())
    }

    /// Whether `requirement` could not be resolved to a concrete version constraint (e.g. an
    /// unexpanded property/variable placeholder rather than a real version or range).
    ///
    /// Default: always resolvable. Ecosystems whose requirement syntax can contain
    /// unresolved placeholders (Maven's `${property}`, Gradle's `$var`/`${var}`) override
    /// this single predicate; both `version_satisfies_requirement`'s "treat as satisfied"
    /// short-circuit and `requirement_status`'s `Unresolved` variant are derived from it, so
    /// the two can't drift out of sync with each other.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    /// use deps_core::{PackageName, VersionReq};
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert!(!DefaultFormatter.requirement_is_unresolved(&VersionReq::new("^1.2")));
    /// ```
    fn requirement_is_unresolved(&self, _requirement: &VersionReq) -> bool {
        false
    }

    /// Tri-state variant of `is_requirement_up_to_date` that distinguishes "confirmed up to
    /// date" from "could not be resolved, so we don't know."
    ///
    /// Default: `Unresolved` when `requirement_is_unresolved` says so, otherwise maps the
    /// boolean result of `is_requirement_up_to_date` to `UpToDate`/`Outdated`. Callers
    /// needing the distinction — inlay hints, in particular — use this instead of
    /// `is_requirement_up_to_date` so they can tell "verified up to date" apart from
    /// "resolution failed."
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::{EcosystemFormatter, RequirementStatus};
    /// use deps_core::{PackageName, VersionReq};
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert_eq!(
    ///     DefaultFormatter.requirement_status(&VersionReq::new("^1.2"), "1.5.0"),
    ///     RequirementStatus::UpToDate
    /// );
    /// assert_eq!(
    ///     DefaultFormatter.requirement_status(&VersionReq::new("^1.2"), "2.0.0"),
    ///     RequirementStatus::Outdated
    /// );
    /// ```
    fn requirement_status(&self, requirement: &VersionReq, latest: &str) -> RequirementStatus {
        if self.requirement_is_unresolved(requirement) {
            return RequirementStatus::Unresolved;
        }
        if self.is_requirement_up_to_date(requirement, latest) {
            RequirementStatus::UpToDate
        } else {
            RequirementStatus::Outdated
        }
    }

    /// Compiles `requirement` into a matcher for precise membership testing against a list
    /// of candidate version strings, or `None` when this ecosystem cannot parse or cannot
    /// model this requirement form — in which case no unsatisfiable-requirement diagnostic
    /// is produced for it.
    ///
    /// Distinct from `version_satisfies_requirement`, which answers the looser "treat as up
    /// to date" question and is deliberately permissive (see that method's docs). This one
    /// gates a WARNING diagnostic claiming "no published version satisfies this
    /// requirement", so it must never guess: an ecosystem that has not opted in by
    /// overriding this method emits no such diagnostic at all, rather than one derived from
    /// a loose heuristic.
    ///
    /// `None` has two distinct causes, both correct to suppress the diagnostic for: the
    /// requirement string fails to parse under this ecosystem's own comparator (`deps-cargo`,
    /// `deps-npm`, `deps-pypi`, `deps-swift` — `.ok()` on a fallible parse), or the
    /// requirement parses fine but names a version-space region the fetched `available` list
    /// structurally cannot contain regardless — a Go pseudo-version, a Composer
    /// dev-branch/`@dev` flag, a RubyGems exact pin indistinguishable from one that matches
    /// only a yanked release, a malformed Maven/Gradle/NuGet range. Scanning either case would
    /// always decide `Some(false)` for every candidate, producing a false "no published
    /// version satisfies" verdict instead of correctly suppressing the check. Implementors of
    /// the second (predicate-guard) shape should use
    /// [`compile_requirement_unless`], which
    /// centralizes this contract instead of re-deriving it per ecosystem. `deps-dart` is the
    /// only ecosystem with neither cause: every requirement string is a valid Dart constraint
    /// by construction, so its override is always `Some`.
    ///
    /// Default: `None` — an ecosystem that has not opted in emits no unsatisfiable-requirement
    /// diagnostics.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    /// use deps_core::{PackageName, VersionReq};
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert!(
    ///     DefaultFormatter
    ///         .compile_requirement(&VersionReq::new("^1.2"))
    ///         .is_none()
    /// );
    /// ```
    fn compile_requirement(
        &self,
        _requirement: &VersionReq,
    ) -> Option<Box<dyn RequirementMatcher>> {
        None
    }

    /// Whether this ecosystem's registry can silently omit a *published* version from
    /// `available` in a way indistinguishable from "never published" — and, if so, whether
    /// `requirement` names a version-space region that specific omission could explain, given
    /// the versions actually observed in `available`.
    ///
    /// Called by [`requirement_is_unsatisfiable`] before compiling `requirement`; returning
    /// `true` suppresses the "no published version satisfies this requirement" diagnostic for
    /// this dependency, the same as [`Self::compile_requirement`] returning `None` — but,
    /// unlike that method, this one sees `available` and can therefore narrow the suppression
    /// instead of disabling it for every requirement of a given shape.
    ///
    /// Default `false` — no ecosystem has this problem unless it opts in. `deps-bundler`
    /// overrides it (see `BundlerFormatter::requirement_is_undecidable_given_available` and
    /// its helper for the RubyGems-specific rationale and heuristic).
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    /// use deps_core::{PackageName, VersionReq};
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert!(!DefaultFormatter.requirement_is_undecidable_given_available(
    ///     &VersionReq::new("1.6.13"),
    ///     &["1.6.9".to_string(), "1.6.14".to_string()],
    /// ));
    /// ```
    fn requirement_is_undecidable_given_available(
        &self,
        _requirement: &VersionReq,
        _available: &[String],
    ) -> bool {
        false
    }

    /// Whether this ecosystem's requirement/version syntax follows strict SemVer 2.0.0
    /// pre-release semantics: a pre-release version (`X.Y.Z-pre`) is excluded from matching
    /// `requirement` unless `requirement` itself pins to the same `X.Y.Z` tuple with a
    /// pre-release tag — the rule Cargo's `semver` crate and npm's `node-semver` both
    /// implement, and that `compile_requirement`'s matcher inherits from its underlying
    /// comparator.
    ///
    /// Used by [`requirement_is_unsatisfiable`]'s caller in `generate_diagnostics_from_cache`
    /// to decide whether the unsatisfiable-requirement WARNING should be enriched with a
    /// mention of a published pre-release that would satisfy `requirement` if pre-release
    /// exclusion were relaxed (#299). Maven/NuGet/Composer/Gradle use non-strict,
    /// ecosystem-specific range models where this premise does not hold — they must not
    /// override this.
    ///
    /// Default `false`. `deps-cargo`, `deps-npm`, and `deps-swift` override this to `true`.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    /// use deps_core::PackageName;
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert!(!DefaultFormatter.strict_semver_prerelease_exclusion());
    /// ```
    fn strict_semver_prerelease_exclusion(&self) -> bool {
        false
    }

    /// Get package URL for hover markdown.
    fn package_url(&self, name: &PackageName) -> String;

    /// Message for yanked/deprecated versions in diagnostics.
    fn yanked_message(&self) -> &'static str {
        "This version has been yanked"
    }

    /// Label for yanked versions in hover.
    fn yanked_label(&self) -> &'static str {
        "*(yanked)*"
    }

    /// Whether the "requirement satisfiable only by a yanked version" diagnostic
    /// (`crate::lsp_helpers::requirement_matches_only_yanked`) should evaluate `requirement`
    /// at all for this ecosystem.
    ///
    /// Default `true` — no restriction, every requirement shape is checked. Override to
    /// `false` for a requirement shape where this ecosystem's `Version::removal_status()` is
    /// not a genuine per-version signal. `NpmFormatter` and `ComposerFormatter` restrict this to
    /// exact-pin requirements: npm's yanked flag is sourced from `deprecated`
    /// (`NpmVersion::deprecated`), and Composer's from `abandoned`
    /// (`ComposerVersion::abandoned`) — both are commonly package-wide (a live-verified
    /// npm package had 126/126 versions marked deprecated), so evaluating a range
    /// requirement against them would flag every dependency on a deprecated/abandoned
    /// package under this diagnostic's wording, conflating it with package-level
    /// deprecation — a distinct, separately-planned diagnostic (issue #205). Restricting to
    /// an exact pin keeps this diagnostic scoped to #247's actual scenario: "you are pinned
    /// to this one specific version, and it has been yanked."
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    /// use deps_core::{PackageName, VersionReq};
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert!(DefaultFormatter.yanked_diagnostic_applies_to(&VersionReq::new("^1.2")));
    /// ```
    fn yanked_diagnostic_applies_to(&self, _requirement: &VersionReq) -> bool {
        true
    }

    /// Detect if cursor position is on a dependency for code actions.
    fn is_position_on_dependency(&self, dep: &dyn Dependency, position: Position) -> bool {
        dep.version_range()
            .is_some_and(|r| position_in_range(position, r))
    }

    /// OSV.dev's canonical spelling for `dep`'s package name, or `None` if
    /// this dependency cannot be mapped (e.g. a non-GitHub Swift package).
    ///
    /// Deliberately **not** routed through [`Self::normalize_package_name`]:
    /// that method produces this project's internal lookup key, while this
    /// one produces the name sent on the wire to OSV. They coincide for most
    /// ecosystems and diverge for NuGet (case-preserving; normalizing would
    /// lowercase it and zero out results), Composer (OSV wants lowercase,
    /// overridden in `deps-composer`), and Swift (prefixed to
    /// `github.com/{owner}/{repo}`, overridden in `deps-swift`). Takes
    /// `&dyn Dependency` rather than `&str` because the Swift override needs
    /// to downcast to inspect the dependency's source URL host — see
    /// `architecture.md` §2.
    ///
    /// The default implementation is the identity: OSV is case-sensitive in
    /// every ecosystem this project supports except PyPI, and for Cargo, npm,
    /// Go, Maven, Gradle, Dart, Bundler, NuGet, and PyPI the manifest's raw
    /// name already matches OSV's canonical spelling.
    fn osv_package_name(&self, dep: &dyn Dependency) -> Option<String> {
        Some(dep.name().to_string())
    }

    /// Converts a version string as it appears in an OSV advisory record
    /// (e.g. [`crate::osv::Advisory::fixed_versions`]) into this ecosystem's
    /// own version namespace, as used in manifests and by the registry.
    ///
    /// Default: identity — correct for ecosystems whose OSV records carry
    /// the native version string verbatim. Override when OSV's namespace
    /// diverges from the native one (Go module versions carry a `v` prefix
    /// that OSV's SEMVER ranges never use).
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::PackageName;
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert_eq!(DefaultFormatter.osv_version_to_native("1.2.3"), "1.2.3");
    /// ```
    fn osv_version_to_native(&self, version: &str) -> String {
        version.to_string()
    }

    /// Rewrites a native-ecosystem version string into the spelling OSV.dev's
    /// SEMVER range matching expects.
    ///
    /// Deliberately the inverse of [`Self::osv_package_name`] rather than a
    /// field on [`crate::osv::ScanTarget`] itself: the caller (`deps-lsp`'s
    /// scan-target builder) has only the native version string at hand, so
    /// each ecosystem's formatter is the natural place to own the transform.
    /// The default implementation is the identity: OSV accepts every
    /// supported ecosystem's native version spelling unchanged except Go,
    /// whose module versions carry a mandatory `v` prefix
    /// (`golang.org/x/mod/module` convention) that OSV's SEMVER matcher
    /// rejects — overridden in `deps-go` to strip it.
    ///
    /// # Examples
    ///
    /// ```
    /// use deps_core::PackageName;
    /// use deps_core::lsp_helpers::EcosystemFormatter;
    ///
    /// struct DefaultFormatter;
    /// impl EcosystemFormatter for DefaultFormatter {
    ///     fn format_version_for_text_edit(&self, version: &str) -> String {
    ///         version.to_string()
    ///     }
    ///     fn package_url(&self, name: &PackageName) -> String {
    ///         name.to_string()
    ///     }
    /// }
    ///
    /// assert_eq!(DefaultFormatter.osv_version("1.2.3"), "1.2.3");
    /// ```
    fn osv_version(&self, version: &str) -> String {
        version.to_string()
    }

    /// Whether `dep`'s manifest version-requirement line is itself the exact
    /// version already selected — never a range.
    ///
    /// True only for a Go `require`-directive dependency: `go.mod`'s
    /// `require` line already holds the module version selected by Go's
    /// MVS, unlike Cargo/npm where the manifest holds a range and the lock
    /// file holds the pin. When true, hover and inlay hints prefer
    /// [`Dependency::version_requirement`] over the lock-file-derived entry
    /// in [`VersionData::resolved`], because `go.sum` is a checksum ledger
    /// that `go get`/`go build` only ever append to (only `go mod tidy`
    /// prunes it) — a stale, no-longer-selected higher version can remain
    /// recorded there after a downgrade and, since go.sum is written sorted
    /// ascending by semver, always sorts last and wins naive
    /// last-occurrence-wins parsing (overridden in `deps-go`; see `#235`).
    ///
    /// Takes `dep` (precedent: [`Self::osv_package_name`]) because Go's
    /// `exclude`/`replace` directives are also surfaced as dependencies
    /// whose `version_requirement()` is *not* an in-use version (the
    /// excluded version, or the replaced-from version) — the `deps-go`
    /// override inspects the directive kind and returns `true` only for
    /// `require`.
    fn manifest_requirement_is_resolved_version(&self, dep: &dyn Dependency) -> bool {
        let _ = dep;
        false
    }
}

/// Whether `segment` is exactly `.` or `..`.
///
/// Unlike ordinary path characters, a literal `.`/`..` segment is not neutralized by
/// percent-encoding: `.` is an unreserved character (RFC 3986), so `urlencoding::encode`
/// leaves it untouched, and the URL parser's dot-segment removal (RFC 3986 §5.2.4) still
/// collapses it after encoding — `%2E` decodes back to `.` before that normalization runs.
/// A registry-fetch URL built as `{base}/{prefix}/{name}` (no fixed suffix after `name`)
/// must reject a `name`/path segment satisfying this predicate rather than encode it,
/// since encoding alone does not stop the collapse (#341, #349).
///
/// Shared by `deps-npm`'s scope/package segment guard and `deps-dart`'s package-name
/// guard — both ecosystems' registry APIs key a fetch on a bare, suffix-less path segment.
///
/// **Scope**: this predicate (and the `#365` regression sweep built around it) guards
/// registry-*fetch* URL builders — the sink is a request this process actually
/// dereferences, so a retargeted URL can make it fetch attacker-chosen data. It
/// deliberately does *not* extend to a "docs link"/`package_url`-style builder (the
/// per-ecosystem hover/display link, e.g. `deps_cargo::crate_url`, `deps_go::package_url`):
/// those interpolate the name into a link rendered in hover text and never fetched by
/// this process, so an unrejected `.`/`..` name there produces at worst a misleading
/// same-host link (the registry's package-listing root), not a traversal off-host (#379).
///
/// # Examples
///
/// ```
/// use deps_core::lsp_helpers::is_dot_segment;
///
/// assert!(is_dot_segment(".."));
/// assert!(is_dot_segment("."));
/// assert!(!is_dot_segment("left-pad"));
/// ```
pub fn is_dot_segment(segment: &str) -> bool {
    segment == "." || segment == ".."
}

/// Whether `version` is safe to embed in a manifest [`TextEdit`] or completion item.
///
/// Guards every call into
/// [`EcosystemFormatter::format_version_replacing`]/[`EcosystemFormatter::format_version_for_text_edit`]
/// and every completion item's `insert_text`/`text_edit`.
///
/// Must be applied to the raw version string *before* formatting, never to a
/// formatter's output: some formatters legitimately produce structural
/// characters in their output from an already-validated version plus fixed,
/// trusted operators (e.g. PyPI's `>=1.2.3,<2`), so validating the output
/// would wrongly reject those.
///
/// An allowlist, not a denylist: `version` must be non-empty, at most 64
/// bytes, and contain only `[A-Za-z0-9.+_~:*^!-]` — the character set real
/// version strings use across every ecosystem this workspace supports
/// (SemVer, PEP 440 including epochs like `1!2.0`, Maven qualifiers, npm's
/// `^`/`~`/`*` range tokens, Go's `+incompatible` suffix). A denylist here
/// would need to anticipate every dangerous token a target manifest format
/// (or a build tool evaluating it, e.g. Gradle's Kotlin/Groovy DSL
/// interpolating `${...}` inside a version literal) could ever act on;
/// failing closed on an unrecognized character is cheaper and safer.
///
/// This is the single validation chokepoint shared by every producer of a
/// version-derived `TextEdit`/completion item in this workspace, including
/// OSV advisory data (an `Advisory.fixed_versions` entry is exactly as
/// untrusted as a registry-reported version).
///
/// # Examples
///
/// ```
/// use deps_core::is_safe_version_string;
///
/// assert!(is_safe_version_string("1.2.3-alpha.1+build"));
/// assert!(!is_safe_version_string("1.2.3\", git = \"https://evil"));
/// ```
pub fn is_safe_version_string(version: &str) -> bool {
    !version.is_empty()
        && version.len() <= 64
        && version.chars().all(|c| {
            c.is_ascii_alphanumeric()
                || matches!(c, '.' | '+' | '_' | '~' | ':' | '*' | '^' | '!' | '-')
        })
}

/// Whether `segment` is safe to embed as a Maven `groupId`/`artifactId` value in a
/// pom.xml [`TextEdit`] or completion item.
///
/// Guards Maven's group/artifact completion producer, which builds a completion item's
/// `insert_text`/`text_edit` from one field of a Maven Central search result — a value
/// type distinct from a version string (see [`is_safe_version_string`]'s doc comment for
/// why version-derived and non-version-derived sinks each get their own allowlist).
///
/// An allowlist, not a denylist: `segment` must be non-empty, at most 128 bytes, not
/// exactly `.`/`..` (see [`is_dot_segment`]), and contain only `[A-Za-z0-9._-]` — the
/// character set real Maven Central group ids (reverse-DNS style, e.g.
/// `org.apache.commons`) and artifact ids (hyphen/underscore separated, e.g.
/// `commons-lang3`) use. Deliberately excludes `:` — the `groupId:artifactId` separator —
/// because this validates one already-split coordinate field at a time, never the joined
/// pair. Failing closed on an unrecognized character (e.g. `<`, `"`, a newline) keeps a
/// malicious/compromised search result from restructuring the pom.xml it's inserted into;
/// the dedicated `.`/`..` rejection closes the same dot-segment URL-normalization gap
/// [`is_dot_segment`] guards elsewhere (`artifactId` reaches a registry-fetch URL as a bare
/// path segment in `deps-maven::registry::metadata_urls`, unlike `groupId`, whose `.`→`/`
/// expansion can never itself produce a literal `..` component).
///
/// # Examples
///
/// ```
/// use deps_core::is_safe_maven_coordinate_segment;
///
/// assert!(is_safe_maven_coordinate_segment("org.apache.commons"));
/// assert!(is_safe_maven_coordinate_segment("commons-lang3"));
/// assert!(!is_safe_maven_coordinate_segment("commons</artifactId><parent>"));
/// assert!(!is_safe_maven_coordinate_segment(".."));
/// ```
pub fn is_safe_maven_coordinate_segment(segment: &str) -> bool {
    !segment.is_empty()
        && segment.len() <= 128
        && !is_dot_segment(segment)
        && segment
            .chars()
            .all(|c| c.is_ascii_alphanumeric() || matches!(c, '.' | '-' | '_'))
}

/// Whether `url` is safe to embed as a Swift Package Manager repository URL in a
/// Package.swift [`TextEdit`] or completion item.
///
/// Guards Swift's URL-completion producer, which builds a `.package(url: "...")`
/// string-literal replacement from a package registry search result's URL — a value
/// type distinct from a version string (see [`is_safe_version_string`]'s doc comment for
/// why version-derived and non-version-derived sinks each get their own allowlist).
///
/// An allowlist, not a denylist: `url` must be non-empty, at most 2048 bytes, start with
/// `https://` — every real Swift package registry response is HTTPS (GitHub's `html_url`
/// never downgrades), so accepting plain `http://` would only hand a
/// compromised/malicious registry a transport-downgrade lever for zero legitimate
/// benefit — and otherwise contain only RFC 3986 URL characters (`A-Za-z0-9` plus
/// `` -._~:/?#[]@!$&'()*+,;=% ``). Deliberately excludes `"`, `\`, control characters,
/// and whitespace — none of those are valid unencoded URL characters, and any of them
/// could close the surrounding Swift string literal or otherwise corrupt the manifest.
/// Failing closed on an unrecognized character keeps a malicious/compromised search
/// result from breaking out of the string it's inserted into.
///
/// # Examples
///
/// ```
/// use deps_core::is_safe_registry_url;
///
/// assert!(is_safe_registry_url("https://github.com/apple/swift-nio"));
/// assert!(!is_safe_registry_url("https://evil.example\", .exact(\"1\")) // "));
/// ```
pub fn is_safe_registry_url(url: &str) -> bool {
    !url.is_empty()
        && url.len() <= 2048
        && url.starts_with("https://")
        && url.chars().all(|c| {
            c.is_ascii_alphanumeric()
                || matches!(
                    c,
                    '-' | '.'
                        | '_'
                        | '~'
                        | ':'
                        | '/'
                        | '?'
                        | '#'
                        | '['
                        | ']'
                        | '@'
                        | '!'
                        | '$'
                        | '&'
                        | '\''
                        | '('
                        | ')'
                        | '*'
                        | '+'
                        | ','
                        | ';'
                        | '='
                        | '%'
                )
        })
}

/// Whether `name` is safe to embed as a package name in a manifest [`TextEdit`] or
/// completion item.
///
/// Guards every arm of `create_package_completion_item`
/// (`crates/deps-lsp/src/handlers/completion.rs`) as a single upfront check, applied
/// before the raw `name` reaches any ecosystem-specific snippet — including Maven and
/// Swift, which additionally validate a *derived* value on top of this gate
/// ([`is_safe_maven_coordinate_segment`] on each split coordinate segment,
/// [`is_safe_registry_url`] on the constructed URL) because a value type distinct from
/// the raw name needs its own allowlist — see [`is_safe_version_string`]'s doc comment
/// for why version-derived and non-version-derived sinks each get their own allowlist.
/// [`PackageName::new`](crate::PackageName::new) is documented as never validating or
/// modifying its input, so this predicate is the first gate a registry-reported name
/// passes through before reaching a manifest. Two sinks that key a bare TOML/YAML
/// entry by `name` (Cargo/PyPI, Dart) additionally quote that key in the snippet, since
/// `.` and `@` are legal here but would otherwise be read as TOML's dotted-key
/// separator or break a YAML plain scalar.
///
/// An allowlist, not a denylist: `name` must be non-empty, at most 256 bytes, and
/// contain only `[A-Za-z0-9._@:/~-]` — the character set real package names use across
/// every ecosystem this predicate guards: Cargo/PyPI/Dart/NuGet/Bundler
/// (alphanumeric, `-`, `_`, `.`), npm/Deno scoped names (`@scope/name`, adding `@` and
/// `/`), Composer (`vendor/package`, `/`), Go module paths (domain-qualified paths like
/// `github.com/org/repo`, `/`, `.`, and `~` — legal in a Go path element and already
/// allowed by [`is_safe_version_string`]/[`is_safe_registry_url`]), and Gradle's
/// colon-delimited `group:artifact` short form (`:`). A denylist here would need to
/// anticipate every dangerous token a target manifest format (TOML/JSON/YAML/XML
/// string literals, a live Kotlin/Groovy build-script DSL) could ever act on; failing
/// closed on an unrecognized character — notably `"`, `'`, `<`, `>`, `` ` ``, and all
/// control characters/newlines — is cheaper and safer.
///
/// # Examples
///
/// ```
/// use deps_core::is_safe_package_name;
///
/// assert!(is_safe_package_name("serde"));
/// assert!(is_safe_package_name("@scope/name"));
/// assert!(is_safe_package_name("org.apache.commons:commons-lang3"));
/// assert!(!is_safe_package_name("evil\"\nbackdoor = \"9.9.9"));
/// ```
pub fn is_safe_package_name(name: &str) -> bool {
    !name.is_empty()
        && name.len() <= 256
        && name.chars().all(|c| {
            c.is_ascii_alphanumeric() || matches!(c, '.' | '_' | '@' | ':' | '/' | '-' | '~')
        })
}

/// Logs a `tracing::warn!` for a value rejected by an `is_safe_*` predicate (or an
/// equivalent value-rejecting gate) before it reaches a manifest edit or registry URL.
///
/// Deliberately logs only `value`'s byte length, never its content: `value` is
/// registry-controlled and, by construction, already failed an allowlist — logging it
/// verbatim at `warn` would let a malicious/compromised registry response inject arbitrary
/// content into this project's own log stream (a second-order log-injection concern),
/// mirroring why `deps-pypi`'s `truncate_for_log` bounds a logged excerpt instead of
/// logging a value verbatim. This is this helper's own contract, not a claim that every
/// `tracing` call site in the workspace avoids logging a raw value — e.g. `deps-lsp`'s
/// `deps-lsp.updateVersion` handler and an OSV malformed-`fixed`-version warning predate
/// this helper and log their rejected value directly; they are unrelated call sites, not a
/// place this helper is used.
///
/// `gate` names the predicate/guard that rejected `value` (e.g.
/// `"is_safe_maven_coordinate_segment"`); `context` is a short description of the call site
/// (e.g. `"maven groupId completion"`).
///
/// # Examples
///
/// ```
/// use deps_core::lsp_helpers::warn_rejected_value;
///
/// warn_rejected_value("is_safe_version_string", "code lens latest version", "1.0.0\"; evil");
/// ```
pub fn warn_rejected_value(gate: &str, context: &str, value: &str) {
    tracing::warn!(
        gate,
        context,
        len = value.len(),
        "rejected unsafe value before manifest/registry sink"
    );
}

/// Builds a single-entry [`WorkspaceEdit::changes`] map replacing `range` in `uri`
/// with `new_text`.
///
/// Shared by every quickfix/refactor code action in `code_actions` that edits exactly
/// one span in the current document (`build_vulnerability_fix_action`,
/// `build_unsatisfiable_fix_action`, and the plain "update to `<version>`" loop in
/// [`generate_code_actions`]).
fn single_file_edit(uri: &Uri, range: Range, new_text: String) -> HashMap<Uri, Vec<TextEdit>> {
    let mut edits = HashMap::new();
    edits.insert(uri.clone(), vec![TextEdit { range, new_text }]);
    edits
}

/// Strips every whitespace character from `s`, so two textually-equivalent strings that
/// differ only in spacing compare equal.
///
/// Shared by every no-op/literal-match guard across `code_actions` and `code_lenses`
/// (`build_vulnerability_fix_action`'s N1 guard, `generate_code_actions`'s REFACTOR-loop
/// guard, `literal_span_matches`, and `collect_update_all_edits`'s no-op guard), all of
/// which compare a declared requirement
/// string against a differently-normalized counterpart — e.g. pep508's `>=1.7, <2.0` vs. a
/// formatter's `>=1.7,<2.0`.
fn strip_whitespace(s: &str) -> String {
    s.chars().filter(|c| !c.is_whitespace()).collect()
}

/// Slices `content` over an LSP `Range` using a pre-built `LineOffsetTable`, returning
/// `""` for an inverted or out-of-bounds range instead of panicking.
///
/// `table` is document-invariant — callers iterating over multiple dependencies in the
/// same document must build it once and reuse it, rather than rebuilding it (an O(n)
/// scan of `content`) per dependency.
fn slice_for_range<'a>(content: &'a str, table: &LineOffsetTable, range: Range) -> &'a str {
    let start = table.position_to_byte_offset(content, range.start);
    let end = table.position_to_byte_offset(content, range.end);
    if start > end {
        return "";
    }
    content.get(start..end).unwrap_or("")
}

/// Checks whether `slice` — `content` sliced over a dependency's `version_range` — still
/// holds the literal version text declared by `requirement`.
///
/// Whitespace is stripped from both sides before comparison, since pep508's normalized
/// requirement string can diverge from the original source spacing (PyPI's `>=1.7,<2.0`
/// renders as `>=1.7, <2.0`) while `version_range` still spans the un-normalized source.
///
/// The second branch accepts `slice` wrapped in brackets matching `requirement` — the
/// exact inverse of NuGet's parser wrapping a bare source version as `format!("[{v}]")`
/// (`crates/deps-nuget/src/parser.rs`). This is deliberately **not** a symmetric bracket
/// strip: NuGet's `Version="1.0.0"` produces requirement `[1.0.0]` over a bare-literal
/// span, so a *symmetric* strip (stripping one bracket pair from both operands) would
/// compare `1.0.0` against `1.0.0` — coincidentally correct there, but the same strip
/// applied to `Version="[1.0.0]"` (requirement `[[1.0.0]]`, a spelling
/// `crates/deps-nuget/src/formatter.rs` explicitly supports) leaves `[1.0.0]` vs
/// `1.0.0` and **falsely rejects** an editable dependency. Wrapping only the slice side
/// handles both spellings without that false reject.
fn literal_span_matches(slice: &str, requirement: &str) -> bool {
    let norm_slice = strip_whitespace(slice);
    let norm_req = strip_whitespace(requirement);
    norm_slice == norm_req || format!("[{norm_slice}]") == norm_req
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::PackageName;
    use crate::lsp_helpers::test_support::*;

    #[test]
    fn test_line_offset_table_line_start_crlf() {
        let table = LineOffsetTable::new("a\r\nbb\r\nc");
        assert_eq!(table.line_start(0), Some(0));
        assert_eq!(table.line_start(1), Some(3));
        assert_eq!(table.line_start(2), Some(7));
        assert_eq!(table.line_start(3), None);
    }

    #[test]
    fn test_byte_offset_to_position_clamps_to_char_boundary_instead_of_panicking() {
        // "é" is a 2-byte UTF-8 sequence; offset 1 lands inside it.
        let content = "é";
        let table = LineOffsetTable::new(content);
        // Must not panic; clamps down to the nearest boundary (offset 0).
        let pos = table.byte_offset_to_position(content, 1);
        assert_eq!(pos, Position::new(0, 0));
    }

    #[test]
    fn test_byte_offset_to_position_multi_byte_boundary_in_longer_line() {
        let content = "ab é cd";
        let table = LineOffsetTable::new(content);
        // Byte 3 is 'é's leading byte (boundary); byte 4 is its continuation
        // byte (not a boundary) and must clamp back to 3 rather than panic.
        assert!(content.is_char_boundary(3));
        assert!(!content.is_char_boundary(4));
        let pos = table.byte_offset_to_position(content, 4);
        assert_eq!(pos, table.byte_offset_to_position(content, 3));
    }

    #[test]
    fn test_position_in_range_inside() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(5, 15);
        assert!(position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_at_start() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(5, 10);
        assert!(position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_at_end() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(5, 20);
        assert!(position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_before() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(5, 5);
        assert!(!position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_after() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(5, 25);
        assert!(!position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_different_line_before() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(4, 15);
        assert!(!position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_different_line_after() {
        let range = Range::new(Position::new(5, 10), Position::new(5, 20));
        let position = Position::new(6, 15);
        assert!(!position_in_range(position, range));
    }

    #[test]
    fn test_position_in_range_multiline() {
        let range = Range::new(Position::new(5, 10), Position::new(7, 5));
        let position = Position::new(6, 0);
        assert!(position_in_range(position, range));
    }

    #[test]
    fn test_escape_markdown_link_breakout_payload() {
        let payload = "real-pkg](https://legit-looking-typosquat.example/download)[real-pkg";
        let escaped = escape_markdown(payload);
        assert_eq!(
            escaped,
            r"real\-pkg\]\(https\:\/\/legit\-looking\-typosquat\.example\/download\)\[real\-pkg"
        );
        assert!(!escaped.contains("]("));
    }

    #[test]
    fn test_escape_markdown_backslash_and_backtick() {
        assert_eq!(escape_markdown(r"a\b`c"), r"a\\b\`c");
    }

    #[test]
    fn test_escape_markdown_autolink_angle_brackets() {
        // `<...>` around a bare URL is a CommonMark autolink; `<`/`>` must be escaped
        // so it cannot render as a live link independent of the `[]`/`()` escaping.
        let escaped = escape_markdown("pkg <https://evil.example>");
        assert_eq!(escaped, r"pkg \<https\:\/\/evil\.example\>");
        assert!(!escaped.contains('<') || escaped.contains(r"\<"));
    }

    #[test]
    fn test_escape_markdown_control_chars_become_spaces() {
        assert_eq!(escape_markdown("a\nb"), "a b");
        assert_eq!(escape_markdown("a\r\nb"), "a  b");
        assert_eq!(escape_markdown("a\tb"), "a b");
        assert_eq!(escape_markdown("a\0b"), "a b");
    }

    #[test]
    fn test_escape_markdown_newline_cannot_break_out_of_heading() {
        // A raw newline used to terminate the ATX heading line early, letting the
        // rest of the name (potentially another "# [...](...)" sequence) render as
        // separate, unescaped Markdown blocks.
        let escaped = escape_markdown("react\n# [fake](https://evil.example)");
        assert!(!escaped.contains('\n'));
    }

    #[test]
    fn test_escape_markdown_hyphenated_name_round_trips_visually() {
        // Escaping a hyphen (ASCII punctuation) is visually inert on render — CommonMark
        // renders `\-` as a literal `-` — so common package names are unaffected in
        // practice even though the raw Markdown source now escapes them.
        assert_eq!(escape_markdown("tokio-util"), r"tokio\-util");
    }

    #[test]
    fn test_markdown_code_span_plain_content() {
        assert_eq!(markdown_code_span("1.0.0"), "`1.0.0`");
    }

    #[test]
    fn test_markdown_code_span_widens_fence_for_embedded_backticks() {
        assert_eq!(markdown_code_span("a`b"), "``a`b``");
        assert_eq!(markdown_code_span("``double``"), "``` ``double`` ```");
    }

    #[test]
    fn test_markdown_code_span_pads_when_content_starts_or_ends_with_backtick() {
        let span = markdown_code_span("`leading");
        assert!(span.starts_with("`` `"));
    }

    #[test]
    fn test_markdown_code_span_replaces_control_chars() {
        let span = markdown_code_span("1.0\n[evil](https://evil.example)");
        assert!(!span.contains('\n'));
    }

    #[test]
    fn test_markdown_code_span_empty_content() {
        assert_eq!(markdown_code_span(""), "` `");
    }

    #[test]
    fn test_markdown_code_span_backtick_payload_cannot_break_span() {
        // A payload attempting to close the code span early and splice in a live
        // link must not succeed regardless of backtick count in the content.
        let payload = "1.0` <https://evil.example>` more";
        let span = markdown_code_span(payload);
        // The fence must be strictly longer than any backtick run in the (sanitized)
        // content, so no substring of `span` after the opening fence can act as a
        // closing fence before the real one.
        let opening_fence_len = span.chars().take_while(|&c| c == '`').count();
        let inner = &span[opening_fence_len..span.len() - opening_fence_len];
        assert!(
            !inner.contains(&"`".repeat(opening_fence_len)),
            "content contains a run of backticks as long as the fence: {span}"
        );
    }

    #[test]
    fn test_is_same_major_minor_full_match() {
        assert!(is_same_major_minor("1.2.3", "1.2.9"));
    }

    #[test]
    fn test_is_same_major_minor_exact_match() {
        assert!(is_same_major_minor("1.2.3", "1.2.3"));
    }

    #[test]
    fn test_is_same_major_minor_major_only_match() {
        assert!(is_same_major_minor("1", "1.2.3"));
        assert!(is_same_major_minor("1.2.3", "1"));
    }

    #[test]
    fn test_is_same_major_minor_no_match_different_minor() {
        assert!(!is_same_major_minor("1.2.3", "1.3.0"));
    }

    #[test]
    fn test_is_same_major_minor_no_match_different_major() {
        assert!(!is_same_major_minor("1.2.3", "2.2.3"));
    }

    #[test]
    fn test_is_same_major_minor_empty_strings() {
        assert!(!is_same_major_minor("", ""));
        assert!(!is_same_major_minor("1.2.3", ""));
        assert!(!is_same_major_minor("", "1.2.3"));
    }

    #[test]
    fn test_is_safe_version_string_accepts_ordinary_versions() {
        assert!(is_safe_version_string("1.2.3"));
        assert!(is_safe_version_string("1.2.3-beta.1+build"));
        assert!(is_safe_version_string("v1.2.3"));
    }

    #[test]
    fn test_is_safe_version_string_rejects_empty_or_whitespace() {
        assert!(!is_safe_version_string(""));
        assert!(!is_safe_version_string("   "));
        assert!(!is_safe_version_string("\t\n"));
    }

    #[test]
    fn test_is_safe_version_string_rejects_control_and_structural_characters() {
        for bad in [
            "1.2.3\n",
            "1.2.3\t",
            "1.2.3\"",
            "1.2.3'",
            "1.2.3<",
            "1.2.3>",
            "1.2.3&",
            "1.2.3\\",
            "1.0.0\", \"malicious\": \"true",
        ] {
            assert!(
                !is_safe_version_string(bad),
                "expected {bad:?} to be rejected"
            );
        }
    }

    #[test]
    fn test_is_safe_version_string_rejects_gradle_interpolation_payload() {
        // Regression (critic S2): `$`/`{`/`}` are outside the allowlist, so a
        // Gradle Kotlin/Groovy `${...}` interpolation payload written into
        // build.gradle(.kts) can never reach a version literal via this gate.
        for bad in ["1.0${System.getenv(\"X\")}", "1.0$var", "${evil}"] {
            assert!(
                !is_safe_version_string(bad),
                "expected {bad:?} to be rejected"
            );
        }
    }

    #[test]
    fn test_is_safe_version_string_rejects_invisible_unicode() {
        // Regression (critic M1): `char::is_control()` alone only covers
        // category Cc — format/separator characters like the bidi override
        // U+202E, zero-width space U+200B, and the JS/JSON5 line terminators
        // U+2028/U+2029 must also be rejected by the allowlist.
        for bad in ["1.2.3\u{202E}", "1.2.3\u{200B}", "1.2.3\u{2028}"] {
            assert!(
                !is_safe_version_string(bad),
                "expected {bad:?} to be rejected"
            );
        }
    }

    #[test]
    fn test_is_safe_version_string_accepts_pep440_epoch() {
        // PEP 440 epochs (`1!2.0`) are legitimate PyPI versions.
        assert!(is_safe_version_string("1!2.0"));
    }

    #[test]
    fn test_is_safe_version_string_length_cap() {
        assert!(is_safe_version_string(&"1".repeat(64)));
        assert!(!is_safe_version_string(&"1".repeat(65)));
    }

    #[test]
    fn test_is_safe_maven_coordinate_segment_accepts_real_ids() {
        assert!(is_safe_maven_coordinate_segment("org.apache.commons"));
        assert!(is_safe_maven_coordinate_segment("commons-lang3"));
        assert!(is_safe_maven_coordinate_segment("jackson-core_2.13"));
    }

    #[test]
    fn test_is_safe_maven_coordinate_segment_rejects_empty() {
        assert!(!is_safe_maven_coordinate_segment(""));
    }

    #[test]
    fn test_is_safe_maven_coordinate_segment_rejects_xml_structural_characters() {
        for bad in [
            "commons</artifactId><parent>",
            "commons\"",
            "commons'",
            "commons&amp;",
            "commons\nlang3",
            "commons\tlang3",
        ] {
            assert!(
                !is_safe_maven_coordinate_segment(bad),
                "expected {bad:?} to be rejected"
            );
        }
    }

    #[test]
    fn test_is_safe_maven_coordinate_segment_rejects_group_artifact_colon() {
        assert!(!is_safe_maven_coordinate_segment(
            "org.apache.commons:commons-lang3"
        ));
    }

    #[test]
    fn test_is_safe_maven_coordinate_segment_length_cap() {
        assert!(is_safe_maven_coordinate_segment(&"a".repeat(128)));
        assert!(!is_safe_maven_coordinate_segment(&"a".repeat(129)));
    }

    #[test]
    fn test_is_safe_registry_url_accepts_real_urls() {
        assert!(is_safe_registry_url("https://github.com/apple/swift-nio"));
        assert!(is_safe_registry_url(
            "https://github.com/apple/swift-nio.git"
        ));
        assert!(is_safe_registry_url("https://github.com/apple/swift%2Dnio"));
    }

    #[test]
    fn test_is_safe_registry_url_rejects_non_https_scheme() {
        // Every real Swift package registry response is HTTPS; accepting `http://` would
        // only hand a compromised registry a transport-downgrade lever.
        assert!(!is_safe_registry_url("http://example.com/repo"));
        assert!(!is_safe_registry_url("file:///etc/passwd"));
        assert!(!is_safe_registry_url("javascript:alert(1)"));
        assert!(!is_safe_registry_url("ftp://example.com/repo"));
        assert!(!is_safe_registry_url(""));
    }

    #[test]
    fn test_is_safe_registry_url_rejects_swift_string_literal_breakout() {
        for bad in [
            "https://evil.example\", .exact(\"1.0.0\")), .package(url: \"https://real",
            "https://evil.example\\",
            "https://evil.example\nlet x = 1",
            "https://evil.example`echo`",
            "https://evil.example<script>",
        ] {
            assert!(
                !is_safe_registry_url(bad),
                "expected {bad:?} to be rejected"
            );
        }
    }

    #[test]
    fn test_is_safe_registry_url_length_cap() {
        let prefix = "https://example.com/";
        let at_cap = format!("{prefix}{}", "a".repeat(2048 - prefix.len()));
        assert_eq!(at_cap.len(), 2048);
        assert!(is_safe_registry_url(&at_cap));

        let over_cap = format!("{at_cap}a");
        assert_eq!(over_cap.len(), 2049);
        assert!(!is_safe_registry_url(&over_cap));
    }

    #[test]
    fn test_is_safe_package_name_accepts_real_names_across_ecosystems() {
        for good in [
            "serde",                            // Cargo
            "requests",                         // PyPI
            "@scope/name",                      // npm/Deno scoped
            "monolog/monolog",                  // Composer vendor/package
            "github.com/org/repo",              // Go module path
            "path",                             // Dart
            "org.apache.commons:commons-lang3", // Gradle group:artifact
            "Newtonsoft.Json",                  // NuGet
            "rails",                            // Bundler
            "npm:react",                        // Deno npm-scheme specifier
            "jsr:@std/fs",                      // Deno jsr-scheme specifier
            "github.com/foo/bar~compat",        // Go path element with `~`
        ] {
            assert!(
                is_safe_package_name(good),
                "expected {good:?} to be accepted"
            );
        }
    }

    #[test]
    fn test_is_safe_package_name_rejects_empty() {
        assert!(!is_safe_package_name(""));
    }

    #[test]
    fn test_is_safe_package_name_rejects_non_ascii() {
        // Deliberately excluded: the allowlist is ASCII-only, so a legacy non-ASCII
        // npm package name (a handful exist, e.g. Unicode-normalized scopes) is
        // rejected rather than risking homograph/normalization tricks in a manifest.
        assert!(!is_safe_package_name("café"));
        assert!(!is_safe_package_name("пакет"));
    }

    #[test]
    fn test_is_safe_package_name_accepts_dot_dot_shapes() {
        // `.`/`/` are individually legal (PyPI dotted names, npm/Composer scopes), so
        // `..`/`../..` pass the charset too. This is not a path-traversal risk: every
        // sink treats `name` as manifest text (a TOML/JSON/YAML/XML value or a
        // string-literal argument), never as a filesystem path.
        assert!(is_safe_package_name(".."));
        assert!(is_safe_package_name("../.."));
    }

    #[test]
    fn test_is_safe_package_name_rejects_structural_breakout_characters() {
        for bad in [
            "evil\"\nbackdoor = \"9.9.9",
            "evil\", git = \"https://evil",
            "evil\\",
            "evil'",
            "evil<script>",
            "evil`echo`",
            "evil\ninjected = true",
            "evil\tname",
        ] {
            assert!(
                !is_safe_package_name(bad),
                "expected {bad:?} to be rejected"
            );
        }
    }

    #[test]
    fn test_is_safe_package_name_length_cap() {
        assert!(is_safe_package_name(&"a".repeat(256)));
        assert!(!is_safe_package_name(&"a".repeat(257)));
    }

    #[test]
    fn test_is_same_major_minor_partial_versions() {
        assert!(is_same_major_minor("1.2", "1.2.3"));
        assert!(is_same_major_minor("1.2.3", "1.2"));
    }

    #[test]
    fn test_ecosystem_formatter_defaults() {
        let formatter = MockFormatter;
        assert_eq!(
            formatter.normalize_package_name(&pkg("test-pkg")),
            "test-pkg"
        );
        assert_eq!(formatter.yanked_message(), "This version has been yanked");
        assert_eq!(formatter.yanked_label(), "*(yanked)*");
    }

    #[test]
    fn test_ecosystem_formatter_version_satisfies() {
        let formatter = MockFormatter;

        assert!(formatter.version_satisfies_requirement("1.2.3", "1.2.3"));

        assert!(formatter.version_satisfies_requirement("1.2.3", "^1.2"));
        assert!(formatter.version_satisfies_requirement("1.2.3", "~1.2"));

        assert!(formatter.version_satisfies_requirement("1.2.3", "1"));
        assert!(formatter.version_satisfies_requirement("1.2.3", "1.2"));

        assert!(!formatter.version_satisfies_requirement("1.2.3", "2.0.0"));
        assert!(!formatter.version_satisfies_requirement("1.2.3", "1.3"));
    }

    #[test]
    fn test_ecosystem_formatter_custom_normalize() {
        struct PyPIFormatter;

        impl EcosystemFormatter for PyPIFormatter {
            fn normalize_package_name(&self, name: &PackageName) -> String {
                name.as_str().to_lowercase().replace('-', "_")
            }

            fn format_version_for_text_edit(&self, version: &str) -> String {
                format!(
                    ">={},<{}",
                    version,
                    version.split('.').next().unwrap_or("0")
                )
            }

            fn package_url(&self, name: &PackageName) -> String {
                format!("https://pypi.org/project/{}", name)
            }
        }

        let formatter = PyPIFormatter;
        assert_eq!(
            formatter.normalize_package_name(&pkg("Test-Package")),
            "test_package"
        );
        assert_eq!(
            formatter.format_version_for_text_edit("1.2.3"),
            ">=1.2.3,<1"
        );
        assert_eq!(
            formatter.package_url(&pkg("requests")),
            "https://pypi.org/project/requests"
        );
    }
}