Fix UI hang and stabilize tests for unusual tuple/list/dict child classes (#9468)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: stephenlf

marimo/_utils/flatten.py

@@ -292,11 +292,14 @@ def _contains_instance(value: Any) -> bool:
             return False
         seen.add(id(value))
 
-        if isinstance(value, (tuple, list)):
-            return any(_contains_instance(v) for v in value)
-        elif isinstance(value, dict):
-            return any(_contains_instance(v) for v in value.values())
-        else:
-            return isinstance(value, instance)
+        try:
+            if isinstance(value, (tuple, list)):
+                return any(_contains_instance(v) for v in value)
+            elif isinstance(value, dict):
+                return any(_contains_instance(v) for v in value.values())
+        except Exception:
+            # .__iter__() or .values() raised. Cannot probe container.
+            return False
+        return isinstance(value, instance)
 
     return _contains_instance(value)

tests/_server/api/endpoints/test_terminal.py

@@ -71,17 +71,25 @@ def test_terminal_ws_wrong_token(client: TestClient) -> None:
 
 
 class TestCreateShellEnvironment:
-    def test_create_shell_environment_default_cwd(self) -> None:
+    def test_create_shell_environment_default_cwd(
+        self, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
         """Test shell environment creation with default working directory."""
+        monkeypatch.delenv("SHELL", raising=False)
+
         shell, env = _create_shell_environment()
 
         assert shell in ["/bin/bash", "/bin/zsh", "/bin/sh"]
         assert env["TERM"] == "xterm-256color"
         assert "LANG" in env
         assert "LC_ALL" in env
 
-    def test_create_shell_environment_custom_cwd(self) -> None:
+    def test_create_shell_environment_custom_cwd(
+        self, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
         """Test shell environment creation with custom working directory."""
+        monkeypatch.delenv("SHELL", raising=False)
+
         with tempfile.TemporaryDirectory() as temp_dir:
             shell, env = _create_shell_environment(cwd=temp_dir)
 
@@ -91,9 +99,14 @@ def test_create_shell_environment_custom_cwd(self) -> None:
     @patch("os.getcwd")
     @patch("pathlib.Path.home")
     def test_create_shell_environment_fallback_cwd(
-        self, mock_home: Mock, mock_getcwd: Mock
+        self,
+        mock_home: Mock,
+        mock_getcwd: Mock,
+        monkeypatch: pytest.MonkeyPatch,
     ) -> None:
         """Test shell environment creation when getcwd fails."""
+        monkeypatch.delenv("SHELL", raising=False)
+
         mock_getcwd.side_effect = OSError("No such directory")
         mock_home.return_value = Path("/home/user")
 
@@ -105,9 +118,14 @@ def test_create_shell_environment_fallback_cwd(
     @patch("os.getcwd")
     @patch("pathlib.Path.home")
     def test_create_shell_environment_ultimate_fallback(
-        self, mock_home: Mock, mock_getcwd: Mock
+        self,
+        mock_home: Mock,
+        mock_getcwd: Mock,
+        monkeypatch: pytest.MonkeyPatch,
     ) -> None:
         """Test shell environment creation when both getcwd and home fail."""
+        monkeypatch.delenv("SHELL", raising=False)
+
         mock_getcwd.side_effect = OSError("No such directory")
         mock_home.side_effect = Exception("No home directory")
 

tests/_utils/test_flatten.py

@@ -325,3 +325,42 @@ class A:
     for _ in range(5):
         value.append(value)
     assert contains_instance(value, A) is True
+
+
+def test_contains_instance_no_iter_tuple() -> None:
+    class NoIterTuple(tuple):
+        def __iter__(self):
+            raise AttributeError("iter throws")
+
+    collection = NoIterTuple((1, 2, 3))
+    assert contains_instance(collection, NoIterTuple) is False
+    assert contains_instance(collection, tuple) is False
+    assert (
+        contains_instance(collection, int) is False
+    )  # Cannot probe opaque collection
+
+
+def test_contains_instance_no_iter_list() -> None:
+    class NoIterList(list):
+        def __iter__(self):
+            raise AttributeError("iter throws")
+
+    collection = NoIterList([1, 2, 3])
+    assert contains_instance(collection, NoIterList) is False
+    assert contains_instance(collection, list) is False
+    assert (
+        contains_instance(collection, int) is False
+    )  # Cannot probe opaque collection
+
+
+def test_contains_instance_no_iter_dict() -> None:
+    class NoValuesDict(dict):
+        def values(self):
+            raise AttributeError("values() throws")
+
+    collection = NoValuesDict({"a": 1, "b": 2, "c": 3})
+    assert contains_instance(collection, NoValuesDict) is False
+    assert contains_instance(collection, dict) is False
+    assert (
+        contains_instance(collection, int) is False
+    )  # Cannot probe opaque collection