fix(is-git-repo): recognize bare repositories (#1266)

* fix(is-git-repo): recognize bare repositories

is_git_repo() used `git rev-parse --show-toplevel` to detect whether
the current directory is inside a git repository. --show-toplevel
fails for bare repositories since they have no working tree, so every
command that relies on this shared helper (e.g. `git browse`) reports
"Not a git repo!" when run from inside a bare repo, even though it
plainly is one.

Switch to `git rev-parse --git-dir`, which succeeds for both normal
and bare repositories and keeps the existing "not a repo" behavior
for non-repo directories.

Fixes #1238, reported and LGTM'd by maintainers there with this exact
fix; no PR had been opened for it yet.

Adds tests/is-git-repo.bats covering: a normal repo, a bare repo, and
a plain (non-repo) directory.

* Fix ruff lint failures in scripts/checkstyle.py

This PR's new Ruff CI job surfaced pre-existing style issues (unsorted
imports, deprecated typing.List/Dict, nested ifs, bare exit()) in
checkstyle.py. Cleaned these up so the newly added lint job passes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

helper/is-git-repo

@@ -3,7 +3,9 @@
 #
 
 is_git_repo() {
-  git rev-parse --show-toplevel > /dev/null 2>&1
+  # --git-dir succeeds for both normal and bare repositories, whereas
+  # --show-toplevel fails inside a bare repository (it has no working tree).
+  git rev-parse --git-dir > /dev/null 2>&1
   result=$?
   if test $result != 0; then
     >&2 echo 'Not a git repo!'

scripts/checkstyle.py

@@ -3,7 +3,7 @@ import argparse
 import os
 import re
 import sys
-from collections.abc import Callable  # Compatibility.
+from collections.abc import Callable  # compat
 from pathlib import Path
 from typing import Any
 
@@ -102,12 +102,11 @@ def lintfile(file: Path, rules: list[Rule], options: dict[str, Any]):
 
         for rule in rules:
             should_run = False
-            # ruff: noqa: SIM102
-            if 'sh' in rule['fileTypes']:
-                if file.name.endswith('.sh'):
+            if 'sh' in rule['fileTypes'] and file.name.endswith('.sh'):
                 should_run = True
-            if 'bash' in rule['fileTypes']:
-                if file.name.endswith('.bash') or file.name.endswith('.bats') or file.name.startswith('git-'):
+            if 'bash' in rule['fileTypes'] and (
+                file.name.endswith('.bash') or file.name.endswith('.bats') or file.name.startswith('git-')
+            ):
                 should_run = True
 
             if options['verbose']:

tests/is-git-repo.bats

@@ -0,0 +1,32 @@
+# shellcheck shell=bash
+
+source "$BATS_TEST_DIRNAME/test_util.sh"
+
+setup_file() {
+	test_util.setup_file
+}
+
+setup() {
+	test_util.cd_test
+}
+
+@test "is_git_repo succeeds inside a normal (non-bare) repository" {
+	test_util.git_init
+
+	run bash "$BATS_TEST_DIRNAME/../helper/is-git-repo"
+	assert_success
+}
+
+@test "is_git_repo succeeds inside a bare repository (see #1238)" {
+	git init --bare --initial-branch main repo.git
+	cd repo.git
+
+	run bash "$BATS_TEST_DIRNAME/../helper/is-git-repo"
+	assert_success
+}
+
+@test "is_git_repo fails outside of a repository" {
+	run bash "$BATS_TEST_DIRNAME/../helper/is-git-repo"
+	assert_failure
+	assert_output 'Not a git repo!'
+}