fix(django): restore process_exception to capture view exceptions

[webjunkie]

Summary

Restores process_exception method removed in v6.7.5, fixing exception capture from Django views.

Problem

Django converts view exceptions to responses before they reach middleware's __call__, so the context manager never sees them. Django provides these via process_exception hook instead.

Timeline

• v6.7.4: had process_exception - worked
• v6.7.5 (PR feat(err): add __acall__ to django middleware #328): removed it with async changes - broke capture (Django middleware is not capturing exceptions, again (regression of #286) #329)
• v6.7.10 (PR fix(django): make middleware truly hybrid-compatible with sync and async Django stacks #348): didn't restore it - still broken
• v6.7.11 (this): restores it

Changes

• Restore process_exception matching v6.7.4 behavior
• Improved tests that properly simulate Django's exception flow
• Version bump + CHANGELOG

Learnings

Django calls process_exception WHILE still in the __call__ context, so tags are already set. Just need to capture the exception directly - no new context needed. First attempt overcomplicated this.

Also: Django checks hasattr() before calling process_exception, so missing it fails silently. Tests needed to simulate this properly (v6.7.5 doesn't raise an error, just doesn't capture).

Tests

21 middleware tests pass. New tests verify:

• Context manager can't see view exceptions (Django catches them)
• process_exception captures exceptions when Django calls it
• Settings (capture_exceptions, request_filter) are respected

Test Validation Across Versions

Validated that tests correctly detect the regression:

• ✅ v6.7.4 (has process_exception): All 4 exception tests PASS
• ❌ v6.7.5 (missing process_exception): test_view_exceptions_only_captured_via_process_exception FAILS with "process_exception missing - view exceptions will not be captured!"
• ✅ v6.7.11 (this PR): All 4 exception tests PASS

Proves tests properly demonstrate Django's exception flow and would have caught the v6.7.5 regression.

Fixes #329

[greptile-apps]

_{4 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

logic: setting _sync_get_response on line 256 has no effect - the middleware uses self.get_response set during initialization. should pass mock_get_response to create_middleware(get_response=mock_get_response) like the first test does.

Suggested change

	def test_process_exception_respects_capture_exceptions_false(self):
	"""Verify process_exception respects capture_exceptions=False setting"""
	mock_client = Mock()
	middleware = self.create_middleware(capture_exceptions=False)
	middleware.client = mock_client
	view_exception = ValueError("Should not be captured")
	def mock_get_response(request):
	if hasattr(middleware, "process_exception"):
	middleware.process_exception(request, view_exception)
	return Mock(status_code=500)
	middleware._sync_get_response = mock_get_response
	request = MockRequest()
	middleware(request)
	mock_client.capture_exception.assert_not_called()
	def test_process_exception_respects_capture_exceptions_false(self):
	"""Verify process_exception respects capture_exceptions=False setting"""
	mock_client = Mock()
	view_exception = ValueError("Should not be captured")
	def mock_get_response(request):
	if hasattr(middleware, "process_exception"):
	middleware.process_exception(request, view_exception)
	return Mock(status_code=500)
	middleware = self.create_middleware(
	capture_exceptions=False, get_response=mock_get_response
	)
	middleware.client = mock_client
	request = MockRequest()
	middleware(request)
	mock_client.capture_exception.assert_not_called()

Prompt To Fix With AI

This is a comment left during a code review.
Path: posthog/test/integrations/test_middleware.py
Line: 242:261

Comment:
**logic:** setting `_sync_get_response` on line 256 has no effect - the middleware uses `self.get_response` set during initialization. should pass `mock_get_response` to `create_middleware(get_response=mock_get_response)` like the first test does.

```suggestion
    def test_process_exception_respects_capture_exceptions_false(self):
        """Verify process_exception respects capture_exceptions=False setting"""
        mock_client = Mock()
        view_exception = ValueError("Should not be captured")

        def mock_get_response(request):
            if hasattr(middleware, "process_exception"):
                middleware.process_exception(request, view_exception)
            return Mock(status_code=500)

        middleware = self.create_middleware(
            capture_exceptions=False, get_response=mock_get_response
        )
        middleware.client = mock_client

        request = MockRequest()
        middleware(request)

        mock_client.capture_exception.assert_not_called()
```

How can I resolve this? If you propose a fix, please make it concise.

[webjunkie]

Check again!

[greptile-apps]

You're right! Looking more carefully at the code structure, I can see the issue now.

The problem is that mock_get_response is defined on line 251, but it's assigned to middleware._sync_get_response on line 256 after the middleware has already been created. However, the middleware was created on line 246 with capture_exceptions=False but without passing the mock_get_response to create_middleware().

When middleware(request) is called on line 259, it will use self.get_response (set during initialization), not _sync_get_response. The assignment on line 256 has no effect.

The fix is to pass mock_get_response to create_middleware() like the first test does:

Suggested change

	def test_process_exception_respects_capture_exceptions_false(self):
	"""Verify process_exception respects capture_exceptions=False setting"""
	mock_client = Mock()
	middleware = self.create_middleware(capture_exceptions=False)
	middleware.client = mock_client
	view_exception = ValueError("Should not be captured")
	def mock_get_response(request):
	if hasattr(middleware, "process_exception"):
	middleware.process_exception(request, view_exception)
	return Mock(status_code=500)
	middleware._sync_get_response = mock_get_response
	request = MockRequest()
	middleware(request)
	mock_client.capture_exception.assert_not_called()
	def test_process_exception_respects_capture_exceptions_false(self):
	"""Verify process_exception respects capture_exceptions=False setting"""
	mock_client = Mock()
	view_exception = ValueError("Should not be captured")
	def mock_get_response(request):
	if hasattr(middleware, "process_exception"):
	middleware.process_exception(request, view_exception)
	return Mock(status_code=500)
	middleware = self.create_middleware(
	capture_exceptions=False, get_response=mock_get_response
	)
	middleware.client = mock_client
	request = MockRequest()
	middleware(request)
	mock_client.capture_exception.assert_not_called()

[greptile-apps]

logic: setting _sync_get_response on line 279 has no effect - the middleware uses self.get_response set during initialization. should pass mock_get_response to create_middleware(get_response=mock_get_response) like the first test does.

Suggested change

	def test_process_exception_respects_request_filter(self):
	"""Verify process_exception respects request_filter setting"""
	mock_client = Mock()
	middleware = self.create_middleware(
	request_filter=lambda req: False, capture_exceptions=True
	)
	middleware.client = mock_client
	view_exception = ValueError("Should be filtered")
	def mock_get_response(request):
	if hasattr(middleware, "process_exception"):
	middleware.process_exception(request, view_exception)
	return Mock(status_code=500)
	middleware._sync_get_response = mock_get_response
	request = MockRequest()
	middleware(request)
	mock_client.capture_exception.assert_not_called()
	def test_process_exception_respects_request_filter(self):
	"""Verify process_exception respects request_filter setting"""
	mock_client = Mock()
	view_exception = ValueError("Should be filtered")
	def mock_get_response(request):
	if hasattr(middleware, "process_exception"):
	middleware.process_exception(request, view_exception)
	return Mock(status_code=500)
	middleware = self.create_middleware(
	request_filter=lambda req: False,
	capture_exceptions=True,
	get_response=mock_get_response,
	)
	middleware.client = mock_client
	request = MockRequest()
	middleware(request)
	mock_client.capture_exception.assert_not_called()

Prompt To Fix With AI

This is a comment left during a code review.
Path: posthog/test/integrations/test_middleware.py
Line: 263:284

Comment:
**logic:** setting `_sync_get_response` on line 279 has no effect - the middleware uses `self.get_response` set during initialization. should pass `mock_get_response` to `create_middleware(get_response=mock_get_response)` like the first test does.

```suggestion
    def test_process_exception_respects_request_filter(self):
        """Verify process_exception respects request_filter setting"""
        mock_client = Mock()
        view_exception = ValueError("Should be filtered")

        def mock_get_response(request):
            if hasattr(middleware, "process_exception"):
                middleware.process_exception(request, view_exception)
            return Mock(status_code=500)

        middleware = self.create_middleware(
            request_filter=lambda req: False,
            capture_exceptions=True,
            get_response=mock_get_response,
        )
        middleware.client = mock_client

        request = MockRequest()
        middleware(request)

        mock_client.capture_exception.assert_not_called()
```

How can I resolve this? If you propose a fix, please make it concise.

[webjunkie]

Check again!

[webjunkie]

@skoob13 I'm testing this as well with a Django 5 project, but in #358 and then do a release I guess.

[skoob13]

LGTM