Backport PR #855: Avoid 500 error messages when current working directory in Jupyter Lab is not a git repo

Author: jeanmonet

.gitignore

@@ -124,3 +124,4 @@ node_modules/
 *.swp
 .devcontainer/
 src/version.ts
+jupyterlab_git/labextension/

jupyterlab_git/git.py

@@ -682,6 +682,11 @@ async def show_top_level(self, current_path):
         if code == 0:
             return {"code": code, "top_repo_path": my_output.strip("\n")}
         else:
+            # Handle special case where cwd not inside a git repo
+            lower_error = my_error.lower()
+            if "fatal: not a git repository" in lower_error:
+                return {"code": 0, "top_repo_path": None}
+
             return {
                 "code": code,
                 "command": " ".join(cmd),

jupyterlab_git/handlers.py

@@ -74,7 +74,7 @@ async def post(self):
         history_count = body["history_count"]
 
         show_top_level = await self.git.show_top_level(current_path)
-        if show_top_level["code"] != 0:
+        if show_top_level.get("top_repo_path") is None:
             self.set_status(500)
             self.finish(json.dumps(show_top_level))
         else:

jupyterlab_git/tests/test_handlers.py

@@ -30,7 +30,7 @@ class TestAllHistory(ServerTest):
     @patch("jupyterlab_git.handlers.GitAllHistoryHandler.git", spec=Git)
     def test_all_history_handler_localbranch(self, mock_git):
         # Given
-        show_top_level = {"code": 0, "foo": "top_level"}
+        show_top_level = {"code": 0, "top_repo_path": "foo"}
         branch = "branch_foo"
         log = "log_foo"
         status = "status_foo"
@@ -63,6 +63,62 @@ def test_all_history_handler_localbranch(self, mock_git):
         }
 
 
+class TestShowTopLevel(ServerTest):
+    @patch("jupyterlab_git.git.execute")
+    def test_git_show_top_level(self, mock_execute):
+        # Given
+        top_repo_path = "path/to/repo"
+
+        mock_execute.return_value = maybe_future((0, str(top_repo_path), ""))
+
+        # When
+        body = {
+            "current_path": top_repo_path + "/subfolder",
+        }
+        response = self.tester.post(["show_top_level"], body=body)
+
+        # Then
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["top_repo_path"] == top_repo_path
+        mock_execute.assert_has_calls(
+            [
+                call(
+                    ["git", "rev-parse", "--show-toplevel"],
+                    cwd=os.path.join(self.notebook_dir, top_repo_path, "subfolder"),
+                ),
+            ]
+        )
+
+    @patch("jupyterlab_git.git.execute")
+    def test_git_show_top_level_not_a_git_repo(self, mock_execute):
+        # Given
+        top_repo_path = "path/to/repo"
+
+        mock_execute.return_value = maybe_future(
+            (128, "", "fatal: not a git repository (or any")
+        )
+
+        # When
+        body = {
+            "current_path": top_repo_path + "/subfolder",
+        }
+        response = self.tester.post(["show_top_level"], body=body)
+
+        # Then
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["top_repo_path"] is None
+        mock_execute.assert_has_calls(
+            [
+                call(
+                    ["git", "rev-parse", "--show-toplevel"],
+                    cwd=os.path.join(self.notebook_dir, top_repo_path, "subfolder"),
+                ),
+            ]
+        )
+
+
 class TestBranch(ServerTest):
     @patch("jupyterlab_git.handlers.GitBranchHandler.git", spec=Git)
     def test_branch_handler_localbranch(self, mock_git):