fix(git): enable core.longpaths for worktree population (#2746) (#2747)

* fix(git): enable core.longpaths for worktree population

Worktrees live under a deep OpenCode data-dir path, so Windows checkouts
of deeply nested repos failed bootstrap with "Filename too long". Enable
Git core.longpaths before git reset --hard (web + VS Code) and surface
clearer path-length guidance when the filesystem still rejects a path.

Fixes #2746

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* chore(vscode): keep ensureWorktreeLongpaths private

Avoid an unused export in the VS Code git service; the helper stays
local to populateWorktreeWithLockRecovery.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/vscode/src/gitService.ts

@@ -1117,34 +1117,71 @@ const getFileIdentity = async (filePath: string): Promise<string | null> => {
   }
 };
 
+// OpenChamber places managed worktrees under a deep data-dir path
+// (`<XDG_DATA_HOME>/opencode/worktree/<40-char project id>/<name>/`). On
+// Windows that prefix plus a deeply nested repo file routinely exceeds
+// MAX_PATH (260). Git can check those paths out when core.longpaths is
+// enabled; without it, `git reset --hard` during bootstrap fails with
+// "Filename too long" and leaves a half-populated worktree (issue #2746).
+const WORKTREE_POPULATE_RESET_ARGS = ['-c', 'core.longpaths=true', 'reset', '--hard'] as const;
+
+const isFilenameTooLongError = (message: string | null | undefined): boolean =>
+  /file ?name too long/i.test(String(message || ''));
+
+const formatWorktreePopulateError = (message: string | null | undefined): string => {
+  const text = String(message || '').trim() || 'Failed to populate worktree';
+  if (!isFilenameTooLongError(text)) {
+    return text;
+  }
+  return [
+    text,
+    'The worktree checkout path exceeds this system\'s path-length limit.',
+    'OpenChamber enables Git `core.longpaths` for worktree population; if this still fails on Windows, enable OS long paths (LongPathsEnabled) or open the repository from a shorter absolute path.',
+  ].join('\n');
+};
+
+const ensureWorktreeLongpaths = async (directory: string): Promise<void> => {
+  const current = await runGitCommand(directory, ['config', '--get', 'core.longpaths']);
+  if (String(current.stdout || '').trim().toLowerCase() === 'true') {
+    return;
+  }
+  // Local config is shared across linked worktrees via the common git dir, so
+  // subsequent OpenChamber and CLI git operations in this repo also get long
+  // path support. Failures here are non-fatal: populate still passes
+  // `-c core.longpaths=true` on reset.
+  await runGitCommand(directory, ['config', 'core.longpaths', 'true']);
+};
+
 const populateWorktreeWithLockRecovery = async (directory: string): Promise<void> => {
-  let result = await runGitCommand(directory, ['reset', '--hard']);
+  await ensureWorktreeLongpaths(directory);
+
+  let result = await runGitCommand(directory, [...WORKTREE_POPULATE_RESET_ARGS]);
   if (result.success) {
     return;
   }
   if (!isIndexLockError(result)) {
-    throw new Error(result.message || 'Failed to populate worktree');
+    throw new Error(formatWorktreePopulateError(result.message));
   }
 
   await wait(WORKTREE_INDEX_LOCK_RETRY_DELAY_MS);
-  result = await runGitCommand(directory, ['reset', '--hard']);
+  result = await runGitCommand(directory, [...WORKTREE_POPULATE_RESET_ARGS]);
   if (result.success) {
     return;
   }
   if (!isIndexLockError(result)) {
-    throw new Error(result.message || 'Failed to populate worktree');
+    throw new Error(formatWorktreePopulateError(result.message));
   }
 
   const lockPath = await getWorktreeIndexLockPath(directory);
   const identity = lockPath ? await getFileIdentity(lockPath) : null;
   await wait(WORKTREE_INDEX_LOCK_STALE_DELAY_MS);
 
-  result = await runGitCommand(directory, ['reset', '--hard']);
+  result = await runGitCommand(directory, [...WORKTREE_POPULATE_RESET_ARGS]);
   if (result.success) {
     return;
   }
   if (!isIndexLockError(result) || !lockPath || !identity || await getFileIdentity(lockPath) !== identity) {
-    throw new Error(result.message || 'Failed to populate worktree');
+    throw new Error(formatWorktreePopulateError(result.message));
   }
 
   await fs.promises.unlink(lockPath).catch((error) => {
@@ -1152,7 +1189,10 @@ const populateWorktreeWithLockRecovery = async (directory: string): Promise<void
       throw error;
     }
   });
-  await runGitCommandOrThrow(directory, ['reset', '--hard'], 'Failed to populate worktree');
+  const finalResult = await runGitCommand(directory, [...WORKTREE_POPULATE_RESET_ARGS]);
+  if (!finalResult.success) {
+    throw new Error(formatWorktreePopulateError(finalResult.message || 'Failed to populate worktree'));
+  }
 };
 
 // Worktrees are created with `git worktree add --no-checkout` and populated