From af69d18a556e1137e6c68bfea8db3a3b99e750e8 Mon Sep 17 00:00:00 2001
From: "S. M. Mohiuddin Khan Shiam" <mohiuddin.khan.shiam@gmail.com>
Date: Fri, 13 Jun 2025 07:29:05 +0600
Subject: [PATCH] Fix: Robust Cross-Platform Fallback for Git Hook Linking in
 [link-hooks.mjs](cci:7://file:///d:/Github/TypeScript/scripts/link-hooks.mjs:0:0-0:0)

Previously, [scripts/link-hooks.mjs](cci:7://file:///d:/Github/TypeScript/scripts/link-hooks.mjs:0:0-0:0) attempted to install git hooks using `fs.linkSync` to create hard links from the source-controlled hook scripts into `.git/hooks`. However, this approach fails on Windows in several common scenarios, such as:

- When the repository is on a FAT/FAT32 drive (no hard link support)
- When the working copy and `.git` are on different volumes (`EXDEV`)
- When the user lacks the required privileges (`EPERM`)

This prevented contributors on such systems from setting up the required git hooks, blocking or complicating development and contribution.

**This PR adds a robust fallback:**
- The script first tries to create a hard link as before.
- If it fails with `EXDEV` or `EPERM`, it falls back to copying the hook file using `fs.copyFileSync`, ensuring the hook is still installed and functional.
- All other errors are still thrown to avoid masking real issues.

This change makes `npm run setup-hooks` reliable on all platforms, improving the onboarding and contribution experience for Windows and cross-device users, while still preferring hard links where possible to keep hooks in sync.

---

**Summary:**
Gracefully fall back to copying git hook scripts if hard-linking fails, ensuring contributors on all platforms can set up hooks without errors.
---
 scripts/link-hooks.mjs | 71 ++++++++++++++++++++++++++----------------
 1 file changed, 44 insertions(+), 27 deletions(-)

diff --git a/scripts/link-hooks.mjs b/scripts/link-hooks.mjs
index 05e1bfc0ddb9a..e3968c718b017 100644
--- a/scripts/link-hooks.mjs
+++ b/scripts/link-hooks.mjs
@@ -1,27 +1,44 @@
-import fs from "fs";
-import path from "path";
-import url from "url";
-
-import { findUpRoot } from "./build/findUpDir.mjs";
-
-const __filename = url.fileURLToPath(new URL(import.meta.url));
-const __dirname = path.dirname(__filename);
-
-const hooks = [
-    "post-checkout",
-    "pre-commit",
-];
-
-hooks.forEach(hook => {
-    const hookInSourceControl = path.resolve(__dirname, "hooks", hook);
-
-    if (fs.existsSync(hookInSourceControl)) {
-        const hookInHiddenDirectory = path.resolve(findUpRoot(), ".git", "hooks", hook);
-
-        if (fs.existsSync(hookInHiddenDirectory)) {
-            fs.unlinkSync(hookInHiddenDirectory);
-        }
-
-        fs.linkSync(hookInSourceControl, hookInHiddenDirectory);
-    }
-});
+import fs from "fs";
+import path from "path";
+import url from "url";
+
+import { findUpRoot } from "./build/findUpDir.mjs";
+
+const __filename = url.fileURLToPath(new URL(import.meta.url));
+const __dirname = path.dirname(__filename);
+
+const hooks = [
+    "post-checkout",
+    "pre-commit",
+];
+
+hooks.forEach(hook => {
+    const hookInSourceControl = path.resolve(__dirname, "hooks", hook);
+
+    if (fs.existsSync(hookInSourceControl)) {
+        const hookInHiddenDirectory = path.resolve(findUpRoot(), ".git", "hooks", hook);
+
+        if (fs.existsSync(hookInHiddenDirectory)) {
+            fs.unlinkSync(hookInHiddenDirectory);
+        }
+
+        // Hard links are ideal to keep hooks in sync with the source-controlled
+        // versions, but they are not always supported. In particular, they can
+        // fail on Windows when the working copy resides on a FAT32 drive or
+        // when the user lacks the required privileges, and they always fail
+        // across device/volume boundaries (EXDEV). Gracefully fall back to a
+        // normal file copy in those scenarios so that contributors on any
+        // platform can still set up git hooks and contribute without friction.
+        try {
+            fs.linkSync(hookInSourceControl, hookInHiddenDirectory);
+        }
+        catch (err) {
+            if (err && (err.code === "EXDEV" || err.code === "EPERM")) {
+                fs.copyFileSync(hookInSourceControl, hookInHiddenDirectory);
+            }
+            else {
+                throw err;
+            }
+        }
+    }
+});