gitweb: Switch default branch name to main for new repositories

I tested additionally that if the root user has already configured
default branch other than main, it is not changed by the gitweb app
setup process.

Signed-off-by: Veiko Aasa <veiko17@disroot.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/gitweb

@@ -142,6 +142,28 @@ def parse_arguments():
 def subcommand_setup(_):
     """Disable default Apache2 Gitweb configuration."""
     action_utils.webserver_disable('gitweb')
+    if not _get_global_default_branch():
+        _set_global_default_branch('main')
+
+
+def _get_global_default_branch():
+    """Get globally configured default branch name."""
+    try:
+        default_branch = subprocess.check_output(
+            ['git', 'config', '--global', '--get',
+             'init.defaultBranch']).decode().strip()
+    except subprocess.CalledProcessError as exception:
+        if exception.returncode == 1:  # Default branch not configured
+            return None
+        raise
+
+    return default_branch
+
+
+def _set_global_default_branch(name):
+    """Configure default branch name globally."""
+    subprocess.check_call(
+        ['git', 'config', '--global', 'init.defaultBranch', name])
 
 
 def _clone_with_progress_report(url, repo_dir):

plinth/modules/gitweb/__init__.py

@@ -42,7 +42,7 @@ class GitwebApp(app_module.App):
 
     app_id = 'gitweb'
 
-    _version = 1
+    _version = 2
 
     def __init__(self):
         """Create components for the app."""

plinth/modules/gitweb/tests/test_views.py

@@ -25,7 +25,7 @@ EXISTING_REPOS = [
         'owner': '',
         'access': 'public',
         'is_private': False,
-        'default_branch': 'master',
+        'default_branch': 'main',
     },
     {
         'name': 'something2',
@@ -33,7 +33,7 @@ EXISTING_REPOS = [
         'owner': '',
         'access': 'private',
         'is_private': True,
-        'default_branch': 'master',
+        'default_branch': 'main',
     },
 ]
 
@@ -59,8 +59,8 @@ def action_run(*args, **kwargs):
 
     elif subcommand == 'get-branches':
         return json.dumps({
-            "default_branch": "master",
-            "branches": ["master", "branch1"]
+            "default_branch": "main",
+            "branches": ["main", "branch1"]
         })
 
     return None
@@ -309,7 +309,7 @@ def test_edit_repository_failed_view(rf):
             'gitweb-name': 'something_other',
             'gitweb-description': 'test-description',
             'gitweb-owner': 'test-owner',
-            'gitweb-default_branch': 'master',
+            'gitweb-default_branch': 'main',
         }
         request = rf.post(
             urls.reverse('gitweb:edit',