Fix discard in linked worktrees

macgit/Services/AdvancedMaintenanceService.swift

@@ -42,12 +42,12 @@ actor AdvancedMaintenanceService {
     func orphanedUndoBackups(in repositories: [URL]) -> OrphanedUndoBackupReport {
         var directories: [URL] = []
         var byteCount: Int64 = 0
+        let snapshotStore = GitFileUndoSnapshotStore()
 
         for repositoryURL in Set(repositories.map(\.standardizedFileURL)) {
-            let root = repositoryURL.appendingPathComponent(
-                ".git/macgit/undo",
-                isDirectory: true
-            )
+            guard let root = try? snapshotStore.undoRoot(in: repositoryURL) else {
+                continue
+            }
             guard let children = try? fileManager.contentsOfDirectory(
                 at: root,
                 includingPropertiesForKeys: [.isDirectoryKey],

macgit/Services/GitFileUndoSnapshotStore.swift

@@ -27,7 +27,7 @@ struct GitFileUndoSnapshotStore {
 
     func capture(paths: [String], in repositoryURL: URL) throws -> GitFileUndoSnapshot {
         let snapshotID = UUID()
-        let directory = snapshotDirectory(snapshotID, in: repositoryURL)
+        let directory = try snapshotDirectory(snapshotID, in: repositoryURL)
         try fileManager.createDirectory(at: directory, withIntermediateDirectories: true)
 
         let items = try paths.map { path in
@@ -56,11 +56,12 @@ struct GitFileUndoSnapshotStore {
     func restore(snapshotID: UUID, in repositoryURL: URL) throws {
         let data = try Data(contentsOf: manifestURL(snapshotID, in: repositoryURL))
         let snapshot = try JSONDecoder().decode(GitFileUndoSnapshot.self, from: data)
+        let snapshotDirectory = try snapshotDirectory(snapshotID, in: repositoryURL)
 
         for item in snapshot.items {
             let destination = repositoryURL.appendingPathComponent(item.path)
             if item.existed, let backupRelativePath = item.backupRelativePath {
-                let backup = snapshotDirectory(snapshotID, in: repositoryURL).appendingPathComponent(backupRelativePath)
+                let backup = snapshotDirectory.appendingPathComponent(backupRelativePath)
                 try fileManager.createDirectory(at: destination.deletingLastPathComponent(), withIntermediateDirectories: true)
                 if fileManager.fileExists(atPath: destination.path) {
                     try fileManager.removeItem(at: destination)
@@ -73,22 +74,58 @@ struct GitFileUndoSnapshotStore {
     }
 
     func delete(snapshotID: UUID, in repositoryURL: URL) throws {
-        let directory = snapshotDirectory(snapshotID, in: repositoryURL)
+        let directory = try snapshotDirectory(snapshotID, in: repositoryURL)
         if fileManager.fileExists(atPath: directory.path) {
             try fileManager.removeItem(at: directory)
         }
         GitUndoSnapshotRegistry.shared.unregister(snapshotID)
     }
 
-    private func undoRoot(in repositoryURL: URL) -> URL {
-        repositoryURL.appendingPathComponent(".git/macgit/undo", isDirectory: true)
+    func undoRoot(in repositoryURL: URL) throws -> URL {
+        try gitDirectory(in: repositoryURL)
+            .appendingPathComponent("macgit/undo", isDirectory: true)
     }
 
-    private func snapshotDirectory(_ id: UUID, in repositoryURL: URL) -> URL {
-        undoRoot(in: repositoryURL).appendingPathComponent(id.uuidString, isDirectory: true)
+    private func gitDirectory(in repositoryURL: URL) throws -> URL {
+        let dotGitURL = repositoryURL.appendingPathComponent(".git")
+        var isDirectory: ObjCBool = false
+
+        if fileManager.fileExists(atPath: dotGitURL.path, isDirectory: &isDirectory),
+           isDirectory.boolValue {
+            return dotGitURL.standardizedFileURL
+        }
+
+        let contents = try String(contentsOf: dotGitURL, encoding: .utf8)
+        let firstLine = contents.split(whereSeparator: \.isNewline).first.map(String.init) ?? ""
+        let prefix = "gitdir:"
+        guard firstLine.hasPrefix(prefix) else {
+            throw GitError.commandFailed("The repository's .git file does not contain a valid gitdir pointer.")
+        }
+
+        let path = firstLine.dropFirst(prefix.count)
+            .trimmingCharacters(in: .whitespaces)
+        guard !path.isEmpty else {
+            throw GitError.commandFailed("The repository's .git file contains an empty gitdir pointer.")
+        }
+
+        let gitDirectory = URL(
+            fileURLWithPath: path,
+            isDirectory: true,
+            relativeTo: dotGitURL.deletingLastPathComponent()
+        ).standardizedFileURL
+        var resolvedIsDirectory: ObjCBool = false
+        guard fileManager.fileExists(atPath: gitDirectory.path, isDirectory: &resolvedIsDirectory),
+              resolvedIsDirectory.boolValue else {
+            throw GitError.commandFailed("The repository's git directory could not be found.")
+        }
+        return gitDirectory
+    }
+
+    private func snapshotDirectory(_ id: UUID, in repositoryURL: URL) throws -> URL {
+        try undoRoot(in: repositoryURL).appendingPathComponent(id.uuidString, isDirectory: true)
     }
 
-    private func manifestURL(_ id: UUID, in repositoryURL: URL) -> URL {
-        snapshotDirectory(id, in: repositoryURL).appendingPathComponent("manifest.json")
+    private func manifestURL(_ id: UUID, in repositoryURL: URL) throws -> URL {
+        try snapshotDirectory(id, in: repositoryURL).appendingPathComponent("manifest.json")
     }
 }

macgitTests/GitFileUndoSnapshotStoreTests.swift

@@ -48,10 +48,76 @@ final class GitFileUndoSnapshotStoreTests: XCTestCase {
         XCTAssertFalse(FileManager.default.fileExists(atPath: repoURL.appendingPathComponent("Missing.txt").path))
     }
 
+    func testCaptureRestoreAndDeleteInLinkedWorktree() throws {
+        let repositoryURL = try makeGitRepository()
+        let worktreeURL = repositoryURL.deletingLastPathComponent()
+            .appendingPathComponent("linked-worktree-\(UUID().uuidString)", isDirectory: true)
+        try runGit(["worktree", "add", "-b", "linked-worktree", worktreeURL.path], in: repositoryURL)
+        addTeardownBlock {
+            try? self.runGit(["worktree", "remove", "--force", worktreeURL.path], in: repositoryURL)
+            try? FileManager.default.removeItem(at: repositoryURL)
+        }
+
+        let gitMarkerURL = worktreeURL.appendingPathComponent(".git")
+        var isDirectory: ObjCBool = false
+        XCTAssertTrue(FileManager.default.fileExists(atPath: gitMarkerURL.path, isDirectory: &isDirectory))
+        XCTAssertFalse(isDirectory.boolValue)
+
+        let fileURL = worktreeURL.appendingPathComponent("Notes.md")
+        try "before\n".write(to: fileURL, atomically: true, encoding: .utf8)
+        let store = GitFileUndoSnapshotStore()
+        let snapshot = try store.capture(paths: ["Notes.md"], in: worktreeURL)
+
+        try "after\n".write(to: fileURL, atomically: true, encoding: .utf8)
+        try store.restore(snapshotID: snapshot.id, in: worktreeURL)
+        XCTAssertEqual(try String(contentsOf: fileURL, encoding: .utf8), "before\n")
+
+        let snapshotDirectory = try store.undoRoot(in: worktreeURL)
+            .appendingPathComponent(snapshot.id.uuidString, isDirectory: true)
+        XCTAssertTrue(FileManager.default.fileExists(atPath: snapshotDirectory.path))
+        try store.delete(snapshotID: snapshot.id, in: worktreeURL)
+        XCTAssertFalse(FileManager.default.fileExists(atPath: snapshotDirectory.path))
+    }
+
     private func makeRepoDirectory() throws -> URL {
         let repoURL = FileManager.default.temporaryDirectory
             .appendingPathComponent("macgit-file-snapshot-\(UUID().uuidString)", isDirectory: true)
         try FileManager.default.createDirectory(at: repoURL.appendingPathComponent(".git"), withIntermediateDirectories: true)
         return repoURL
     }
+
+    private func makeGitRepository() throws -> URL {
+        let repositoryURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("macgit-file-snapshot-repository-\(UUID().uuidString)", isDirectory: true)
+        try FileManager.default.createDirectory(at: repositoryURL, withIntermediateDirectories: true)
+        try runGit(["init", "-b", "main"], in: repositoryURL)
+        try runGit(["config", "user.name", "Mac Git Tests"], in: repositoryURL)
+        try runGit(["config", "user.email", "tests@example.com"], in: repositoryURL)
+        try "base\n".write(
+            to: repositoryURL.appendingPathComponent("README.md"),
+            atomically: true,
+            encoding: .utf8
+        )
+        try runGit(["add", "README.md"], in: repositoryURL)
+        try runGit(["commit", "-m", "initial"], in: repositoryURL)
+        return repositoryURL
+    }
+
+    private func runGit(_ arguments: [String], in repositoryURL: URL) throws {
+        let task = Process()
+        task.executableURL = URL(fileURLWithPath: "/usr/bin/git")
+        task.arguments = arguments
+        task.currentDirectoryURL = repositoryURL
+        let stderr = Pipe()
+        task.standardError = stderr
+        try task.run()
+        task.waitUntilExit()
+        if task.terminationStatus != 0 {
+            let output = String(
+                data: stderr.fileHandleForReading.readDataToEndOfFile(),
+                encoding: .utf8
+            ) ?? "git failed"
+            throw GitError.commandFailed(output)
+        }
+    }
 }