[GIT-213] fix: return HTTP response from dispatch() exception handler (#9179)

* fix(api): return HTTP response from dispatch() exception handler

BaseAPIView.dispatch() and BaseViewSet.dispatch() built the proper
error Response via handle_exception() but returned the raw exception
object instead, causing Django to raise
"TypeError: 'Exception' object is not a valid HTTP response".

Fix all six occurrences across the api, app, license and space view
bases, and add a regression test covering every affected base class.

Fixes #9157

* chore(api): add copyright header to tests/unit/views/__init__.py

The empty package init file was missing the AGPL copyright header,
failing the Copy Right Check CI (addlicense -check on all tracked
.py files).

apps/api/plane/api/views/base.py

@@ -110,7 +110,7 @@ class BaseAPIView(TimezoneMixin, GenericAPIView, ReadReplicaControlMixin, BasePa
             return response
         except Exception as exc:
             response = self.handle_exception(exc)
-            return exc
+            return response
 
     def finalize_response(self, request, response, *args, **kwargs):
         # Call super to get the default response

apps/api/plane/app/views/base.py

@@ -120,7 +120,7 @@ class BaseViewSet(TimezoneMixin, ReadReplicaControlMixin, ModelViewSet, BasePagi
             return response
         except Exception as exc:
             response = self.handle_exception(exc)
-            return exc
+            return response
 
     @property
     def workspace_slug(self):
@@ -215,7 +215,7 @@ class BaseAPIView(TimezoneMixin, ReadReplicaControlMixin, APIView, BasePaginator
 
         except Exception as exc:
             response = self.handle_exception(exc)
-            return exc
+            return response
 
     @property
     def workspace_slug(self):

apps/api/plane/license/api/views/base.py

@@ -106,7 +106,7 @@ class BaseAPIView(TimezoneMixin, APIView, BasePaginator):
 
         except Exception as exc:
             response = self.handle_exception(exc)
-            return exc
+            return response
 
     @property
     def fields(self):

apps/api/plane/space/views/base.py

@@ -114,7 +114,7 @@ class BaseViewSet(TimezoneMixin, ModelViewSet, BasePaginator):
             return response
         except Exception as exc:
             response = self.handle_exception(exc)
-            return exc
+            return response
 
     @property
     def workspace_slug(self):
@@ -197,7 +197,7 @@ class BaseAPIView(TimezoneMixin, APIView, BasePaginator):
 
         except Exception as exc:
             response = self.handle_exception(exc)
-            return exc
+            return response
 
     @property
     def workspace_slug(self):

apps/api/plane/tests/unit/views/__init__.py

@@ -0,0 +1,3 @@
+# Copyright (c) 2023-present Plane Software, Inc. and contributors
+# SPDX-License-Identifier: AGPL-3.0-only
+# See the LICENSE file for details.

apps/api/plane/tests/unit/views/test_base_dispatch.py

@@ -0,0 +1,69 @@
+# Copyright (c) 2023-present Plane Software, Inc. and contributors
+# SPDX-License-Identifier: AGPL-3.0-only
+# See the LICENSE file for details.
+
+"""
+Regression tests for the ``dispatch()`` exception handling on the shared
+``BaseAPIView`` / ``BaseViewSet`` classes.
+
+When ``super().dispatch()`` raises an unhandled exception, ``dispatch()`` must
+return the HTTP ``Response`` produced by ``handle_exception()`` -- not the raw
+exception object. Returning the exception causes Django's response pipeline to
+fail with ``TypeError: 'Exception' object is not a valid HTTP response``.
+
+See: https://github.com/makeplane/plane/issues/9157
+"""
+
+import pytest
+from unittest.mock import patch
+
+from rest_framework import status
+from rest_framework.response import Response
+from rest_framework.test import APIRequestFactory
+
+from plane.api.views.base import BaseAPIView as ApiBaseAPIView, BaseViewSet as ApiBaseViewSet
+from plane.app.views.base import BaseAPIView as AppBaseAPIView, BaseViewSet as AppBaseViewSet
+from plane.license.api.views.base import BaseAPIView as LicenseBaseAPIView
+from plane.space.views.base import BaseAPIView as SpaceBaseAPIView, BaseViewSet as SpaceBaseViewSet
+
+
+# Every shared base view that wraps ``super().dispatch()`` in a try/except.
+VIEW_CLASSES = [
+    ApiBaseAPIView,
+    ApiBaseViewSet,
+    AppBaseAPIView,
+    AppBaseViewSet,
+    LicenseBaseAPIView,
+    SpaceBaseAPIView,
+    SpaceBaseViewSet,
+]
+
+
+@pytest.mark.unit
+@pytest.mark.parametrize(
+    "view_class",
+    VIEW_CLASSES,
+    ids=lambda c: f"{c.__module__}.{c.__name__}",
+)
+def test_dispatch_returns_response_when_super_dispatch_raises(view_class):
+    """dispatch() must return handle_exception()'s Response, not the exception."""
+    request = APIRequestFactory().get("/api/test/")
+    view = view_class()
+
+    sentinel = Response(
+        {"error": "Something went wrong please try again later"},
+        status=status.HTTP_500_INTERNAL_SERVER_ERROR,
+    )
+
+    with (
+        patch("rest_framework.views.APIView.dispatch", side_effect=RuntimeError("boom")),
+        patch.object(view_class, "handle_exception", return_value=sentinel) as mock_handle,
+    ):
+        result = view.dispatch(request)
+
+    mock_handle.assert_called_once()
+    assert isinstance(result, Response), (
+        f"{view_class.__module__}.{view_class.__name__}.dispatch() returned "
+        f"{type(result).__name__} instead of an HTTP Response"
+    )
+    assert result is sentinel