fallow_config/

workspace.rs

use std::io::Read as _;
use std::path::{Path, PathBuf};

use schemars::JsonSchema;
use serde::{Deserialize, Serialize};

/// Workspace configuration for monorepo support.
#[derive(Debug, Clone, Deserialize, Serialize, JsonSchema)]
pub struct WorkspaceConfig {
    /// Additional workspace patterns (beyond what's in root package.json).
    #[serde(default)]
    pub patterns: Vec<String>,
}

/// Discovered workspace info from package.json, pnpm-workspace.yaml, or tsconfig.json references.
#[derive(Debug, Clone)]
pub struct WorkspaceInfo {
    /// Workspace root path.
    pub root: PathBuf,
    /// Package name from package.json.
    pub name: String,
    /// Whether this workspace is depended on by other workspaces.
    pub is_internal_dependency: bool,
}

/// Discover all workspace packages in a monorepo.
///
/// Sources (additive, deduplicated by canonical path):
/// 1. `package.json` `workspaces` field
/// 2. `pnpm-workspace.yaml` `packages` field
/// 3. `tsconfig.json` `references` field (TypeScript project references)
pub fn discover_workspaces(root: &Path) -> Vec<WorkspaceInfo> {
    let mut patterns = Vec::new();

    // 1. Check root package.json for workspace patterns
    let pkg_path = root.join("package.json");
    if let Ok(pkg) = PackageJson::load(&pkg_path) {
        patterns.extend(pkg.workspace_patterns());
    }

    // 2. Check pnpm-workspace.yaml
    let pnpm_workspace = root.join("pnpm-workspace.yaml");
    if pnpm_workspace.exists()
        && let Ok(content) = std::fs::read_to_string(&pnpm_workspace)
    {
        patterns.extend(parse_pnpm_workspace_yaml(&content));
    }

    // Pre-compute canonical root once for security checks
    let canonical_root = root.canonicalize().unwrap_or_else(|_| root.to_path_buf());
    let mut workspaces = Vec::new();

    // 3. Expand package.json/pnpm workspace patterns to find workspace directories
    if !patterns.is_empty() {
        // Separate positive and negated patterns.
        // Negated patterns (e.g., `!**/test/**`) are used as exclusion filters —
        // the `glob` crate does not support `!` prefixed patterns natively.
        let (positive, negative): (Vec<&String>, Vec<&String>) =
            patterns.iter().partition(|p| !p.starts_with('!'));
        let negation_matchers: Vec<globset::GlobMatcher> = negative
            .iter()
            .filter_map(|p| {
                let stripped = p.strip_prefix('!').unwrap_or(p);
                globset::Glob::new(stripped)
                    .ok()
                    .map(|g| g.compile_matcher())
            })
            .collect();

        for pattern in &positive {
            // Normalize the pattern for directory matching:
            // - `packages/*` → glob for `packages/*` (find all subdirs)
            // - `packages/` → glob for `packages/*` (trailing slash means "contents of")
            // - `apps`       → glob for `apps` (exact directory)
            let glob_pattern = if pattern.ends_with('/') {
                format!("{pattern}*")
            } else if !pattern.contains('*') && !pattern.contains('?') && !pattern.contains('{') {
                // Bare directory name — treat as exact match
                (*pattern).clone()
            } else {
                (*pattern).clone()
            };

            // Walk directories matching the glob
            let matched_dirs = expand_workspace_glob(root, &glob_pattern, &canonical_root);
            for dir in matched_dirs {
                // Skip workspace entries that point to the project root itself
                // (e.g. pnpm-workspace.yaml listing `.` as a workspace)
                let canonical_dir = dir.canonicalize().unwrap_or_else(|_| dir.clone());
                if canonical_dir == canonical_root {
                    continue;
                }

                // Check against negation patterns — skip directories that match any negated pattern
                let relative = dir.strip_prefix(root).unwrap_or(&dir);
                let relative_str = relative.to_string_lossy();
                if negation_matchers
                    .iter()
                    .any(|m| m.is_match(relative_str.as_ref()))
                {
                    continue;
                }

                let ws_pkg_path = dir.join("package.json");
                if ws_pkg_path.exists()
                    && let Ok(pkg) = PackageJson::load(&ws_pkg_path)
                {
                    // Collect dependency names during initial load to avoid
                    // re-reading package.json in step 5.
                    let dep_names = pkg.all_dependency_names();
                    let name = pkg.name.unwrap_or_else(|| {
                        dir.file_name()
                            .map(|n| n.to_string_lossy().to_string())
                            .unwrap_or_default()
                    });
                    workspaces.push((
                        WorkspaceInfo {
                            root: dir,
                            name,
                            is_internal_dependency: false,
                        },
                        dep_names,
                    ));
                }
            }
        }
    }

    // 4. Check root tsconfig.json for TypeScript project references.
    // Referenced directories are added as workspaces, supplementing npm/pnpm workspaces.
    // This enables cross-workspace resolution for TypeScript composite projects.
    for dir in parse_tsconfig_references(root) {
        let canonical_dir = dir.canonicalize().unwrap_or_else(|_| dir.clone());
        // Security: skip references pointing to project root or outside it
        if canonical_dir == canonical_root || !canonical_dir.starts_with(&canonical_root) {
            continue;
        }

        // Read package.json if available; otherwise use directory name
        let ws_pkg_path = dir.join("package.json");
        let (name, dep_names) = if ws_pkg_path.exists() {
            if let Ok(pkg) = PackageJson::load(&ws_pkg_path) {
                let deps = pkg.all_dependency_names();
                let n = pkg.name.unwrap_or_else(|| dir_name(&dir));
                (n, deps)
            } else {
                (dir_name(&dir), Vec::new())
            }
        } else {
            // No package.json — use directory name, no deps.
            // Valid for TypeScript-only composite projects.
            (dir_name(&dir), Vec::new())
        };

        workspaces.push((
            WorkspaceInfo {
                root: dir,
                name,
                is_internal_dependency: false,
            },
            dep_names,
        ));
    }

    if workspaces.is_empty() {
        return Vec::new();
    }

    // 5. Deduplicate workspaces by canonical path.
    // Overlapping sources (npm workspaces + tsconfig references pointing to the same
    // directory) are collapsed. npm-discovered entries take precedence (they appear first).
    {
        let mut seen = rustc_hash::FxHashSet::default();
        workspaces.retain(|(ws, _)| {
            let canonical = ws.root.canonicalize().unwrap_or_else(|_| ws.root.clone());
            seen.insert(canonical)
        });
    }

    // 6. Mark workspaces that are depended on by other workspaces.
    // Uses dep names collected during initial package.json load (step 3)
    // to avoid re-reading all workspace package.json files.
    let all_dep_names: rustc_hash::FxHashSet<String> = workspaces
        .iter()
        .flat_map(|(_, deps)| deps.iter().cloned())
        .collect();
    for (ws, _) in &mut workspaces {
        ws.is_internal_dependency = all_dep_names.contains(&ws.name);
    }

    workspaces.into_iter().map(|(ws, _)| ws).collect()
}

/// Extract the directory name as a string, for workspace name fallback.
fn dir_name(dir: &Path) -> String {
    dir.file_name()
        .map(|n| n.to_string_lossy().to_string())
        .unwrap_or_default()
}

/// Parse `tsconfig.json` at the project root and extract `references[].path` directories.
///
/// Returns directories that exist on disk. tsconfig.json is JSONC (comments + trailing commas),
/// so we strip both before parsing.
fn parse_tsconfig_references(root: &Path) -> Vec<PathBuf> {
    let tsconfig_path = root.join("tsconfig.json");
    let Ok(content) = std::fs::read_to_string(&tsconfig_path) else {
        return Vec::new();
    };

    // Strip UTF-8 BOM if present (common in Windows-authored tsconfig files)
    let content = content.trim_start_matches('\u{FEFF}');

    // Strip JSONC comments
    let mut stripped = String::new();
    if json_comments::StripComments::new(content.as_bytes())
        .read_to_string(&mut stripped)
        .is_err()
    {
        return Vec::new();
    }

    // Strip trailing commas (common in tsconfig.json)
    let cleaned = strip_trailing_commas(&stripped);

    let Ok(value) = serde_json::from_str::<serde_json::Value>(&cleaned) else {
        return Vec::new();
    };

    let Some(refs) = value.get("references").and_then(|v| v.as_array()) else {
        return Vec::new();
    };

    refs.iter()
        .filter_map(|r| {
            r.get("path").and_then(|p| p.as_str()).map(|p| {
                // strip_prefix removes exactly one leading "./" (unlike trim_start_matches
                // which would strip repeatedly)
                let cleaned = p.strip_prefix("./").unwrap_or(p);
                root.join(cleaned)
            })
        })
        .filter(|p| p.is_dir())
        .collect()
}

/// Strip trailing commas before `]` and `}` in JSON-like content.
///
/// tsconfig.json commonly uses trailing commas which are valid JSONC but not valid JSON.
/// This strips them so `serde_json` can parse the content.
fn strip_trailing_commas(input: &str) -> String {
    let bytes = input.as_bytes();
    let len = bytes.len();
    let mut result = Vec::with_capacity(len);
    let mut in_string = false;
    let mut i = 0;

    while i < len {
        let b = bytes[i];

        if in_string {
            result.push(b);
            if b == b'\\' && i + 1 < len {
                // Push escaped character and skip it
                i += 1;
                result.push(bytes[i]);
            } else if b == b'"' {
                in_string = false;
            }
            i += 1;
            continue;
        }

        if b == b'"' {
            in_string = true;
            result.push(b);
            i += 1;
            continue;
        }

        if b == b',' {
            // Look ahead past whitespace for ] or }
            let mut j = i + 1;
            while j < len && bytes[j].is_ascii_whitespace() {
                j += 1;
            }
            if j < len && (bytes[j] == b']' || bytes[j] == b'}') {
                // Skip the trailing comma
                i += 1;
                continue;
            }
        }

        result.push(b);
        i += 1;
    }

    // We only removed ASCII commas and preserved all other bytes unchanged,
    // so the result is valid UTF-8 if the input was. Use from_utf8 to be safe.
    String::from_utf8(result).unwrap_or_else(|_| input.to_string())
}

/// Expand a workspace glob pattern to matching directories.
///
/// Uses the `glob` crate for full glob support including `**` (deep matching).
/// `canonical_root` is pre-computed to avoid repeated `canonicalize()` syscalls.
#[expect(clippy::print_stderr)]
fn expand_workspace_glob(root: &Path, pattern: &str, canonical_root: &Path) -> Vec<PathBuf> {
    let full_pattern = root.join(pattern).to_string_lossy().to_string();
    match glob::glob(&full_pattern) {
        Ok(paths) => paths
            .filter_map(Result::ok)
            .filter(|p| p.is_dir())
            .filter(|p| {
                // Security: ensure workspace directory is within project root
                p.canonicalize()
                    .ok()
                    .is_some_and(|cp| cp.starts_with(canonical_root))
            })
            .collect(),
        Err(e) => {
            eprintln!("Warning: Invalid workspace glob pattern '{pattern}': {e}");
            Vec::new()
        }
    }
}

/// Parse pnpm-workspace.yaml to extract package patterns.
fn parse_pnpm_workspace_yaml(content: &str) -> Vec<String> {
    // Simple YAML parsing for the common format:
    // packages:
    //   - 'packages/*'
    //   - 'apps/*'
    let mut patterns = Vec::new();
    let mut in_packages = false;

    for line in content.lines() {
        let trimmed = line.trim();
        if trimmed == "packages:" {
            in_packages = true;
            continue;
        }
        if in_packages {
            if trimmed.starts_with("- ") {
                let value = trimmed
                    .strip_prefix("- ")
                    .unwrap_or(trimmed)
                    .trim_matches('\'')
                    .trim_matches('"');
                patterns.push(value.to_string());
            } else if !trimmed.is_empty() && !trimmed.starts_with('#') {
                break; // New top-level key
            }
        }
    }

    patterns
}

/// Type alias for standard `HashMap` used in serde-deserialized structs.
/// `rustc-hash` v2 does not have a `serde` feature, so fields deserialized
/// from JSON must use `std::collections::HashMap`.
#[expect(clippy::disallowed_types)]
type StdHashMap<K, V> = std::collections::HashMap<K, V>;

/// Parsed package.json with fields relevant to fallow.
#[derive(Debug, Clone, Default, Deserialize, Serialize)]
pub struct PackageJson {
    #[serde(default)]
    pub name: Option<String>,
    #[serde(default)]
    pub main: Option<String>,
    #[serde(default)]
    pub module: Option<String>,
    #[serde(default)]
    pub types: Option<String>,
    #[serde(default)]
    pub typings: Option<String>,
    #[serde(default)]
    pub source: Option<String>,
    #[serde(default)]
    pub browser: Option<serde_json::Value>,
    #[serde(default)]
    pub bin: Option<serde_json::Value>,
    #[serde(default)]
    pub exports: Option<serde_json::Value>,
    #[serde(default)]
    pub dependencies: Option<StdHashMap<String, String>>,
    #[serde(default, rename = "devDependencies")]
    pub dev_dependencies: Option<StdHashMap<String, String>>,
    #[serde(default, rename = "peerDependencies")]
    pub peer_dependencies: Option<StdHashMap<String, String>>,
    #[serde(default)]
    pub scripts: Option<StdHashMap<String, String>>,
    #[serde(default)]
    pub workspaces: Option<serde_json::Value>,
}

impl PackageJson {
    /// Load from a package.json file.
    pub fn load(path: &std::path::Path) -> Result<Self, String> {
        let content = std::fs::read_to_string(path)
            .map_err(|e| format!("Failed to read {}: {}", path.display(), e))?;
        serde_json::from_str(&content)
            .map_err(|e| format!("Failed to parse {}: {}", path.display(), e))
    }

    /// Get all dependency names (production + dev + peer).
    pub fn all_dependency_names(&self) -> Vec<String> {
        let mut deps = Vec::new();
        if let Some(d) = &self.dependencies {
            deps.extend(d.keys().cloned());
        }
        if let Some(d) = &self.dev_dependencies {
            deps.extend(d.keys().cloned());
        }
        if let Some(d) = &self.peer_dependencies {
            deps.extend(d.keys().cloned());
        }
        deps
    }

    /// Get production dependency names only.
    pub fn production_dependency_names(&self) -> Vec<String> {
        self.dependencies
            .as_ref()
            .map(|d| d.keys().cloned().collect())
            .unwrap_or_default()
    }

    /// Get dev dependency names only.
    pub fn dev_dependency_names(&self) -> Vec<String> {
        self.dev_dependencies
            .as_ref()
            .map(|d| d.keys().cloned().collect())
            .unwrap_or_default()
    }

    /// Extract entry points from package.json fields.
    pub fn entry_points(&self) -> Vec<String> {
        let mut entries = Vec::new();

        if let Some(main) = &self.main {
            entries.push(main.clone());
        }
        if let Some(module) = &self.module {
            entries.push(module.clone());
        }
        if let Some(types) = &self.types {
            entries.push(types.clone());
        }
        if let Some(typings) = &self.typings {
            entries.push(typings.clone());
        }
        if let Some(source) = &self.source {
            entries.push(source.clone());
        }

        // Handle browser field (string or object with path values)
        if let Some(browser) = &self.browser {
            match browser {
                serde_json::Value::String(s) => entries.push(s.clone()),
                serde_json::Value::Object(map) => {
                    for v in map.values() {
                        if let serde_json::Value::String(s) = v
                            && (s.starts_with("./") || s.starts_with("../"))
                        {
                            entries.push(s.clone());
                        }
                    }
                }
                _ => {}
            }
        }

        // Handle bin field (string or object)
        if let Some(bin) = &self.bin {
            match bin {
                serde_json::Value::String(s) => entries.push(s.clone()),
                serde_json::Value::Object(map) => {
                    for v in map.values() {
                        if let serde_json::Value::String(s) = v {
                            entries.push(s.clone());
                        }
                    }
                }
                _ => {}
            }
        }

        // Handle exports field (recursive)
        if let Some(exports) = &self.exports {
            extract_exports_entries(exports, &mut entries);
        }

        entries
    }

    /// Extract workspace patterns from package.json.
    pub fn workspace_patterns(&self) -> Vec<String> {
        match &self.workspaces {
            Some(serde_json::Value::Array(arr)) => arr
                .iter()
                .filter_map(|v| v.as_str().map(String::from))
                .collect(),
            Some(serde_json::Value::Object(obj)) => obj
                .get("packages")
                .and_then(|v| v.as_array())
                .map(|arr| {
                    arr.iter()
                        .filter_map(|v| v.as_str().map(String::from))
                        .collect()
                })
                .unwrap_or_default(),
            _ => Vec::new(),
        }
    }
}

/// Recursively extract file paths from package.json exports field.
fn extract_exports_entries(value: &serde_json::Value, entries: &mut Vec<String>) {
    match value {
        serde_json::Value::String(s) => {
            if s.starts_with("./") || s.starts_with("../") {
                entries.push(s.clone());
            }
        }
        serde_json::Value::Object(map) => {
            for v in map.values() {
                extract_exports_entries(v, entries);
            }
        }
        serde_json::Value::Array(arr) => {
            for v in arr {
                extract_exports_entries(v, entries);
            }
        }
        _ => {}
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn parse_pnpm_workspace_basic() {
        let yaml = "packages:\n  - 'packages/*'\n  - 'apps/*'\n";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert_eq!(patterns, vec!["packages/*", "apps/*"]);
    }

    #[test]
    fn parse_pnpm_workspace_double_quotes() {
        let yaml = "packages:\n  - \"packages/*\"\n  - \"apps/*\"\n";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert_eq!(patterns, vec!["packages/*", "apps/*"]);
    }

    #[test]
    fn parse_pnpm_workspace_no_quotes() {
        let yaml = "packages:\n  - packages/*\n  - apps/*\n";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert_eq!(patterns, vec!["packages/*", "apps/*"]);
    }

    #[test]
    fn parse_pnpm_workspace_empty() {
        let yaml = "";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert!(patterns.is_empty());
    }

    #[test]
    fn parse_pnpm_workspace_no_packages_key() {
        let yaml = "other:\n  - something\n";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert!(patterns.is_empty());
    }

    #[test]
    fn parse_pnpm_workspace_with_comments() {
        let yaml = "packages:\n  # Comment\n  - 'packages/*'\n";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert_eq!(patterns, vec!["packages/*"]);
    }

    #[test]
    fn parse_pnpm_workspace_stops_at_next_key() {
        let yaml = "packages:\n  - 'packages/*'\ncatalog:\n  react: ^18\n";
        let patterns = parse_pnpm_workspace_yaml(yaml);
        assert_eq!(patterns, vec!["packages/*"]);
    }

    #[test]
    fn strip_trailing_commas_basic() {
        assert_eq!(
            strip_trailing_commas(r#"{"a": 1, "b": 2,}"#),
            r#"{"a": 1, "b": 2}"#
        );
    }

    #[test]
    fn strip_trailing_commas_array() {
        assert_eq!(strip_trailing_commas(r#"[1, 2, 3,]"#), r#"[1, 2, 3]"#);
    }

    #[test]
    fn strip_trailing_commas_with_whitespace() {
        assert_eq!(
            strip_trailing_commas("{\n  \"a\": 1,\n}"),
            "{\n  \"a\": 1\n}"
        );
    }

    #[test]
    fn strip_trailing_commas_preserves_strings() {
        // Commas inside strings should NOT be stripped
        assert_eq!(
            strip_trailing_commas(r#"{"a": "hello,}"}"#),
            r#"{"a": "hello,}"}"#
        );
    }

    #[test]
    fn strip_trailing_commas_nested() {
        let input = r#"{"refs": [{"path": "./a",}, {"path": "./b",},],}"#;
        let expected = r#"{"refs": [{"path": "./a"}, {"path": "./b"}]}"#;
        assert_eq!(strip_trailing_commas(input), expected);
    }

    #[test]
    fn strip_trailing_commas_escaped_quotes() {
        assert_eq!(
            strip_trailing_commas(r#"{"a": "he\"llo,}",}"#),
            r#"{"a": "he\"llo,}"}"#
        );
    }

    #[test]
    fn tsconfig_references_from_dir() {
        let temp_dir = std::env::temp_dir().join("fallow-test-tsconfig-refs");
        let _ = std::fs::remove_dir_all(&temp_dir);
        std::fs::create_dir_all(temp_dir.join("packages/core")).unwrap();
        std::fs::create_dir_all(temp_dir.join("packages/ui")).unwrap();

        std::fs::write(
            temp_dir.join("tsconfig.json"),
            r#"{
                // Root tsconfig with project references
                "references": [
                    {"path": "./packages/core"},
                    {"path": "./packages/ui"},
                ],
            }"#,
        )
        .unwrap();

        let refs = parse_tsconfig_references(&temp_dir);
        assert_eq!(refs.len(), 2);
        assert!(refs.iter().any(|p| p.ends_with("packages/core")));
        assert!(refs.iter().any(|p| p.ends_with("packages/ui")));

        let _ = std::fs::remove_dir_all(&temp_dir);
    }

    #[test]
    fn tsconfig_references_no_file() {
        let refs = parse_tsconfig_references(std::path::Path::new("/nonexistent"));
        assert!(refs.is_empty());
    }

    #[test]
    fn tsconfig_references_no_references_field() {
        let temp_dir = std::env::temp_dir().join("fallow-test-tsconfig-no-refs");
        let _ = std::fs::remove_dir_all(&temp_dir);
        std::fs::create_dir_all(&temp_dir).unwrap();

        std::fs::write(
            temp_dir.join("tsconfig.json"),
            r#"{"compilerOptions": {"strict": true}}"#,
        )
        .unwrap();

        let refs = parse_tsconfig_references(&temp_dir);
        assert!(refs.is_empty());

        let _ = std::fs::remove_dir_all(&temp_dir);
    }

    #[test]
    fn tsconfig_references_skips_nonexistent_dirs() {
        let temp_dir = std::env::temp_dir().join("fallow-test-tsconfig-missing-dir");
        let _ = std::fs::remove_dir_all(&temp_dir);
        std::fs::create_dir_all(temp_dir.join("packages/core")).unwrap();

        std::fs::write(
            temp_dir.join("tsconfig.json"),
            r#"{"references": [{"path": "./packages/core"}, {"path": "./packages/missing"}]}"#,
        )
        .unwrap();

        let refs = parse_tsconfig_references(&temp_dir);
        assert_eq!(refs.len(), 1);
        assert!(refs[0].ends_with("packages/core"));

        let _ = std::fs::remove_dir_all(&temp_dir);
    }

    #[test]
    fn discover_workspaces_from_tsconfig_references() {
        let temp_dir = std::env::temp_dir().join("fallow-test-ws-tsconfig-refs");
        let _ = std::fs::remove_dir_all(&temp_dir);
        std::fs::create_dir_all(temp_dir.join("packages/core")).unwrap();
        std::fs::create_dir_all(temp_dir.join("packages/ui")).unwrap();

        // No package.json workspaces — only tsconfig references
        std::fs::write(
            temp_dir.join("tsconfig.json"),
            r#"{"references": [{"path": "./packages/core"}, {"path": "./packages/ui"}]}"#,
        )
        .unwrap();

        // core has package.json with a name
        std::fs::write(
            temp_dir.join("packages/core/package.json"),
            r#"{"name": "@project/core"}"#,
        )
        .unwrap();

        // ui has NO package.json — name should fall back to directory name
        let workspaces = discover_workspaces(&temp_dir);
        assert_eq!(workspaces.len(), 2);
        assert!(workspaces.iter().any(|ws| ws.name == "@project/core"));
        assert!(workspaces.iter().any(|ws| ws.name == "ui"));

        let _ = std::fs::remove_dir_all(&temp_dir);
    }

    #[test]
    fn tsconfig_references_outside_root_rejected() {
        let temp_dir = std::env::temp_dir().join("fallow-test-tsconfig-outside");
        let _ = std::fs::remove_dir_all(&temp_dir);
        std::fs::create_dir_all(temp_dir.join("project/packages/core")).unwrap();
        // "outside" is a sibling of "project", not inside it
        std::fs::create_dir_all(temp_dir.join("outside")).unwrap();

        std::fs::write(
            temp_dir.join("project/tsconfig.json"),
            r#"{"references": [{"path": "./packages/core"}, {"path": "../outside"}]}"#,
        )
        .unwrap();

        // Security: "../outside" points outside the project root and should be rejected
        let workspaces = discover_workspaces(&temp_dir.join("project"));
        assert_eq!(
            workspaces.len(),
            1,
            "reference outside project root should be rejected: {workspaces:?}"
        );
        assert!(
            workspaces[0]
                .root
                .to_string_lossy()
                .contains("packages/core")
        );

        let _ = std::fs::remove_dir_all(&temp_dir);
    }

    #[test]
    fn package_json_workspace_patterns_array() {
        let pkg: PackageJson =
            serde_json::from_str(r#"{"workspaces": ["packages/*", "apps/*"]}"#).unwrap();
        let patterns = pkg.workspace_patterns();
        assert_eq!(patterns, vec!["packages/*", "apps/*"]);
    }

    #[test]
    fn package_json_workspace_patterns_object() {
        let pkg: PackageJson =
            serde_json::from_str(r#"{"workspaces": {"packages": ["packages/*"]}}"#).unwrap();
        let patterns = pkg.workspace_patterns();
        assert_eq!(patterns, vec!["packages/*"]);
    }

    #[test]
    fn package_json_workspace_patterns_none() {
        let pkg: PackageJson = serde_json::from_str(r#"{"name": "test"}"#).unwrap();
        let patterns = pkg.workspace_patterns();
        assert!(patterns.is_empty());
    }

    #[test]
    fn package_json_workspace_patterns_empty_array() {
        let pkg: PackageJson = serde_json::from_str(r#"{"workspaces": []}"#).unwrap();
        let patterns = pkg.workspace_patterns();
        assert!(patterns.is_empty());
    }

    #[test]
    fn package_json_load_valid() {
        let temp_dir = std::env::temp_dir().join("fallow-test-pkg-json");
        let _ = std::fs::create_dir_all(&temp_dir);
        let pkg_path = temp_dir.join("package.json");
        std::fs::write(&pkg_path, r#"{"name": "test", "main": "index.js"}"#).unwrap();

        let pkg = PackageJson::load(&pkg_path).unwrap();
        assert_eq!(pkg.name, Some("test".to_string()));
        assert_eq!(pkg.main, Some("index.js".to_string()));

        let _ = std::fs::remove_dir_all(&temp_dir);
    }

    #[test]
    fn package_json_load_missing_file() {
        let result = PackageJson::load(std::path::Path::new("/nonexistent/package.json"));
        assert!(result.is_err());
    }

    #[test]
    fn package_json_entry_points_combined() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "main": "dist/index.js",
            "module": "dist/index.mjs",
            "types": "dist/index.d.ts",
            "typings": "dist/types.d.ts"
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        assert_eq!(entries.len(), 4);
        assert!(entries.contains(&"dist/index.js".to_string()));
        assert!(entries.contains(&"dist/index.mjs".to_string()));
        assert!(entries.contains(&"dist/index.d.ts".to_string()));
        assert!(entries.contains(&"dist/types.d.ts".to_string()));
    }

    #[test]
    fn package_json_exports_nested() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "exports": {
                ".": {
                    "import": "./dist/index.mjs",
                    "require": "./dist/index.cjs"
                },
                "./utils": {
                    "import": "./dist/utils.mjs"
                }
            }
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        assert!(entries.contains(&"./dist/index.mjs".to_string()));
        assert!(entries.contains(&"./dist/index.cjs".to_string()));
        assert!(entries.contains(&"./dist/utils.mjs".to_string()));
    }

    #[test]
    fn package_json_exports_array() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "exports": {
                ".": ["./dist/index.mjs", "./dist/index.cjs"]
            }
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        assert!(entries.contains(&"./dist/index.mjs".to_string()));
        assert!(entries.contains(&"./dist/index.cjs".to_string()));
    }

    #[test]
    fn extract_exports_ignores_non_relative() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "exports": {
                ".": "not-a-relative-path"
            }
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        // "not-a-relative-path" doesn't start with "./" so should be excluded
        assert!(entries.is_empty());
    }

    #[test]
    fn package_json_source_field() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "main": "dist/index.js",
            "source": "src/index.ts"
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        assert!(entries.contains(&"src/index.ts".to_string()));
        assert!(entries.contains(&"dist/index.js".to_string()));
    }

    #[test]
    fn package_json_browser_field_string() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "browser": "./dist/browser.js"
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        assert!(entries.contains(&"./dist/browser.js".to_string()));
    }

    #[test]
    fn package_json_browser_field_object() {
        let pkg: PackageJson = serde_json::from_str(
            r#"{
            "browser": {
                "./server.js": "./browser.js",
                "module-name": false
            }
        }"#,
        )
        .unwrap();
        let entries = pkg.entry_points();
        assert!(entries.contains(&"./browser.js".to_string()));
        // non-relative paths and false values should be excluded
        assert_eq!(entries.len(), 1);
    }
}