From 2d5a6a678a779bd7e8198da6c1a69b2f00a3d847 Mon Sep 17 00:00:00 2001
From: Alberto De Bortoli <albertodebortoli@gmail.com>
Date: Thu, 9 Apr 2026 00:14:51 +0100
Subject: [PATCH] Skip post-checkout hook installation in git worktrees
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In a git worktree, `.git` is a regular file (containing a gitdir
pointer) rather than a directory. The previous code used
`fileExists(atPath:)` to detect whether the current directory was
a git repository, but that method returns true for both files and
directories. As a result, `GitHookInstaller` would proceed past the
guard and attempt to copy the hook to `.git/hooks/post-checkout` —
a path that cannot exist when `.git` is a file — causing an error.

Additionally, when the post-checkout hook fires in a worktree context
(git shares the main repo's hooks across all worktrees), it invokes
`luca install`, which would re-trigger the same failing installation.

Fix: after confirming `.git` exists, check that it is a directory
using `attributesOfItem(atPath:)`. If it is a file (worktree), return
early — hooks are owned by the main repository.

Add `attributesOfItem(atPath:)` to `GitHookInstallerFileManaging` and
a new test covering the worktree case.
---
 .../GitHookInstallerFileManaging.swift           |  1 +
 .../Core/GitHookInstaller/GitHookInstaller.swift |  6 ++++++
 Tests/Core/GitHookInstallerTests.swift           | 16 ++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/Sources/LucaCore/Core/FileManagerProtocols/GitHookInstallerFileManaging.swift b/Sources/LucaCore/Core/FileManagerProtocols/GitHookInstallerFileManaging.swift
index b630ac9..d5b5b35 100644
--- a/Sources/LucaCore/Core/FileManagerProtocols/GitHookInstallerFileManaging.swift
+++ b/Sources/LucaCore/Core/FileManagerProtocols/GitHookInstallerFileManaging.swift
@@ -12,4 +12,5 @@ public protocol GitHookInstallerFileManaging {
     func readString(at url: URL) throws -> String
     func writeString(_ content: String, to url: URL) throws
     func setAttributes(_ attributes: [FileAttributeKey: Any], ofItemAtPath path: String) throws
+    func attributesOfItem(atPath path: String) throws -> [FileAttributeKey: Any]
 }
diff --git a/Sources/LucaCore/Core/GitHookInstaller/GitHookInstaller.swift b/Sources/LucaCore/Core/GitHookInstaller/GitHookInstaller.swift
index ba74c6a..b527ebb 100644
--- a/Sources/LucaCore/Core/GitHookInstaller/GitHookInstaller.swift
+++ b/Sources/LucaCore/Core/GitHookInstaller/GitHookInstaller.swift
@@ -30,6 +30,12 @@ public struct GitHookInstaller {
             return
         }
 
+        // In a git worktree, `.git` is a file (not a directory) pointing to the main repo.
+        // Hooks live in the main repo; skip installation to avoid failing in a worktree context.
+        guard (try? fileManager.attributesOfItem(atPath: gitDirectory.path)[.type] as? FileAttributeType) == .typeDirectory else {
+            return
+        }
+
         let sourceHookPath = fileManager.homeDirectoryForCurrentUser
             .appending(components: Constants.toolFolder, "post-checkout")
 
diff --git a/Tests/Core/GitHookInstallerTests.swift b/Tests/Core/GitHookInstallerTests.swift
index eb691e4..52b8d7d 100644
--- a/Tests/Core/GitHookInstallerTests.swift
+++ b/Tests/Core/GitHookInstallerTests.swift
@@ -40,6 +40,22 @@ final class GitHookInstallerTests: XCTestCase {
         XCTAssertTrue(printer.printedMessages.isEmpty)
     }
 
+    // MARK: - Git Worktree
+
+    func test_installPostCheckoutHook_whenGitWorktree_doesNothing() throws {
+        // Given: `.git` is a file (worktree), not a directory
+        let currentDirectory = URL(fileURLWithPath: fileManager.currentDirectoryPath)
+        try fileManager.createDirectory(at: currentDirectory, withIntermediateDirectories: true)
+        let gitFile = currentDirectory.appending(component: ".git")
+        _ = fileManager.createFile(atPath: gitFile.path, contents: Data("gitdir: /some/main/repo/.git/worktrees/feature\n".utf8))
+
+        // When
+        try sut.installPostCheckoutHook()
+
+        // Then
+        XCTAssertTrue(printer.printedMessages.isEmpty)
+    }
+
     // MARK: - Source Hook Missing
 
     func test_installPostCheckoutHook_whenSourceHookMissing_printsWarning() throws {