gitweb: Improve error handling when creating repository

If an error occurs during creation of a git repository, delete possibly
corrupted git repository directory and show more specific error message.

Closes #1829

Tests performed:
- Gitweb unit and functional tests pass
- Create a small disk for git repositories:
  > dd if=/dev/zero of=disk.img iflag=fullblock bs=128k count=100 && sync
  > mkfs.ext4 disk.img
  > mount -o loop disk.img /var/lib/git/
- Clone a large repository https://salsa.debian.org/freedombox-team/plinth
  Disk got full during cloning remote repository. Repository listing do not
  show this repository anymore. (No errors is shown to the user.)
- Fill disk space:
  > head -c 1G </dev/urandom > /var/lib/git/myfile
- Disk is full. Cloning an existing remote repository fails with an error
  message (No space left on device)
- Disk is full. Creating a new repository fails with an error message
  (No space left on device)

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

actions/gitweb

@@ -156,8 +156,11 @@ def _clone_with_progress_report(url, repo_dir):
         if currenttime - starttime > 1:
             elapsed = _clone_status_line_to_percent(line)
             if elapsed is not None:
-                with open(status_file, 'w') as file_handle:
-                    file_handle.write(elapsed)
+                try:
+                    with open(status_file, 'w') as file_handle:
+                        file_handle.write(elapsed)
+                except OSError as error:
+                    errors.append(str(error))
 
             starttime = currenttime
 
@@ -183,12 +186,15 @@ def _prepare_clone_repo(arguments):
     repo_dir = os.path.join(GIT_REPO_PATH, repo_name)
     os.mkdir(repo_dir)
 
-    if arguments.is_private:
-        _set_access_status(repo_name, 'private')
-
     status_file = os.path.join(repo_dir, 'clone_progress')
-    with open(status_file, 'w') as file_handle:
-        file_handle.write('0')
+    try:
+        if arguments.is_private:
+            _set_access_status(repo_name, 'private')
+        with open(status_file, 'w') as file_handle:
+            file_handle.write('0')
+    except OSError:
+        shutil.rmtree(repo_dir)
+        raise
 
 
 def _clone_status_line_to_percent(line):
@@ -238,14 +244,21 @@ def _clone_repo(arguments):
 def _create_repo(arguments):
     """Create an empty repository."""
     repo = arguments.name
-    subprocess.check_call(['git', 'init', '--bare', repo], cwd=GIT_REPO_PATH)
-    if not arguments.keep_ownership:
-        subprocess.check_call(['chown', '-R', 'www-data:www-data', repo],
+    try:
+        subprocess.check_call(['git', 'init', '--bare', repo],
                               cwd=GIT_REPO_PATH)
-    _set_repo_description(repo, arguments.description)
-    _set_repo_owner(repo, arguments.owner)
-    if arguments.is_private:
-        _set_access_status(repo, 'private')
+        if not arguments.keep_ownership:
+            subprocess.check_call(['chown', '-R', 'www-data:www-data', repo],
+                                  cwd=GIT_REPO_PATH)
+        _set_repo_description(repo, arguments.description)
+        _set_repo_owner(repo, arguments.owner)
+        if arguments.is_private:
+            _set_access_status(repo, 'private')
+    except (subprocess.CalledProcessError, OSError):
+        repo_path = os.path.join(GIT_REPO_PATH, repo)
+        if os.path.isdir(repo_path):
+            shutil.rmtree(repo_path)
+        raise
 
 
 def _get_repo_description(repo):

plinth/modules/gitweb/tests/test_views.py

@@ -146,8 +146,10 @@ def test_create_repo_invalid_name_view(rf):
 
 def test_create_repo_failed_view(rf):
     """Test that repo creation failure sends correct error message."""
-    with patch('plinth.modules.gitweb.create_repo',
-               side_effect=ActionError('Error')):
+    general_error_message = "An error occurred while creating the repository."
+    error_description = 'some error'
+    with patch('plinth.modules.gitweb.create_repo', side_effect=ActionError(
+            'gitweb', '', error_description)):
         form_data = {
             'gitweb-name': 'something_other',
             'gitweb-description': '',
@@ -157,8 +159,8 @@ def test_create_repo_failed_view(rf):
         view = views.CreateRepoView.as_view()
         response, messages = make_request(request, view)
 
-        assert list(messages)[
-            0].message == 'An error occurred while creating the repository.'
+        assert list(messages)[0].message == '{0} {1}'.format(
+            general_error_message, error_description)
         assert response.status_code == 302
 
 

plinth/modules/gitweb/views.py

@@ -60,11 +60,15 @@ class CreateRepoView(SuccessMessageMixin, FormView):
         try:
             gitweb.create_repo(form_data['name'], form_data['description'],
                                form_data['owner'], form_data['is_private'])
-        except ActionError:
+        except ActionError as error:
+            self.success_message = ''
+            error_text = error.args[2].split('\n')[0]
             messages.error(
-                self.request,
-                _('An error occurred while creating the repository.'))
-        gitweb.app.update_service_access()
+                self.request, "{0} {1}".format(
+                    _('An error occurred while creating the repository.'),
+                    error_text))
+        else:
+            gitweb.app.update_service_access()
 
         return super().form_valid(form)