fix(vcs): improve GitLab error handling

Show the actual error from the request.

Fixes WEBLATE-39D7

Author: nijel

weblate/vcs/git.py

@@ -2120,12 +2120,21 @@ def get_headers(self, credentials: GitCredentials) -> dict[str, str]:
         return headers
 
     def get_target_project_id(self, credentials: GitCredentials):
-        response_data, _response, error = self.request(
+        response_data, response, error = self.request(
             "get", credentials, credentials["url"]
         )
         if "id" not in response_data:
-            report_error("Could not get project", message=True)
-            raise RepositoryError(0, f"Could not get project: {error}")
+            detail = error or response.reason or gettext("Unknown error")
+            report_error(
+                "Could not get GitLab project",
+                message=True,
+                extra_log=f"{response.status_code}: {detail}",
+            )
+            raise RepositoryError(
+                0,
+                gettext("Could not get GitLab project (%(status)s): %(error)s")
+                % {"status": response.status_code, "error": detail},
+            )
         return response_data["id"]
 
     def configure_fork_features(

weblate/vcs/tests/test_vcs.py

@@ -2039,6 +2039,33 @@ def test_push_rejected(self, branch: str = "") -> None:
         )
         self.assertEqual(call_count, 1)
 
+    @responses.activate
+    def test_get_target_project_id_auth_error(self) -> None:
+        responses.add(
+            responses.GET,
+            "https://gitlab.com/api/v4/projects/WeblateOrg%2Ftest",
+            json={
+                "error": "invalid_token",
+                "error_description": "Token is expired.",
+            },
+            status=401,
+        )
+
+        with (
+            patch("weblate.vcs.git.report_error") as mock_report_error,
+            self.assertRaisesMessage(
+                RepositoryError,
+                "Could not get GitLab project (401): invalid_token, Token is expired.",
+            ),
+        ):
+            self.repo.get_target_project_id(self.repo.get_credentials())
+
+        mock_report_error.assert_called_once_with(
+            "Could not get GitLab project",
+            message=True,
+            extra_log="401: invalid_token, Token is expired.",
+        )
+
     @responses.activate
     def test_pull_request_error(self, branch: str = "") -> None:
         # Patch push_to_fork() function because we don't want to actually