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@Aaditya1273 Aaditya1273 commented Oct 15, 2025

fix: ApphookReloadMiddleware not handling new languages causing reverse exception

  • Add signal handler for PageContent creation to trigger URL reloading
  • Only triggers for pages with apphooks to minimize performance impact
  • Prevents NoReverseMatch exceptions when creating language variants
  • Add comprehensive test suite with 5 test cases
  • Maintains backward compatibility

Fixes #8357

Description

This PR fixes issue #8357 where creating new language variants for pages with apphooks causes django.urls.exceptions.NoReverseMatch exceptions until the server is restarted.

Problem

When a page with an apphook exists in one language and you create a new language variant, the URL patterns are not reloaded. This causes NoReverseMatch exceptions when trying to reverse URLs for the apphook in the new language, even after creating the language variant for the apphook page itself.

Root Cause

The ApphookReloadMiddleware only triggers URL reloading when:

  • The apphook itself changes (application_urls field)
  • The slug changes for a page with an apphook
  • Pages are deleted

But it does NOT trigger when new language variants are created for pages with apphooks.

Solution

Added a signal handler that triggers URL reloading when new PageContent objects (language variants) are created for pages that have apphooks configured.

Changes Made

  1. cms/signals/pagecontent.py (NEW) - Added post_save signal handler for PageContent model that triggers set_restart_trigger() when new language variants are created for apphook pages
  2. cms/signals/__init__.py (MODIFIED) - Added import to ensure the new signal handler is connected
  3. cms/tests/test_apphook_reload_language_variants.py (NEW) - Comprehensive test suite with 5 test cases covering all scenarios

Key Features

  • Only triggers on creation, not updates
  • Only triggers for pages with apphooks (minimal performance impact)
  • Uses existing set_restart_trigger() mechanism
  • Fully backward compatible
  • Well-tested with comprehensive coverage

Example

Before this fix:

# Create page with apphook
page = create_page("Products", "template.html", "en", application_urls="ProductApp")
# Create German variant
create_page_content("de", "Produkte", page=page)
# This would fail with NoReverseMatch
reverse('product_list')  # ❌ Exception until server restart

## Summary by Sourcery

Add a PageContent post_save signal handler to trigger URL reloading when new language variants are created for apphook pages, preventing NoReverseMatch errors until server restart.

Bug Fixes:
- Prevent NoReverseMatch errors by reloading URLs when new language variants are created for pages with apphooks

Enhancements:
- Introduce a PageContent post_save signal handler to invoke set_restart_trigger only on creation of apphook pages

Tests:
- Add comprehensive test suite with five cases covering URL reload on new language variants, no reload for non-apphook pages, and no triggers on updates

- Add signal handler for PageContent creation to trigger URL reloading
- Only triggers for pages with apphooks to minimize performance impact
- Prevents NoReverseMatch exceptions when creating language variants
- Add comprehensive test suite with 5 test cases
- Maintains backward compatibility

Fixes django-cms#8357
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sourcery-ai bot commented Oct 15, 2025

Reviewer's Guide

This PR extends the ApphookReloadMiddleware mechanism by adding a post_save signal handler for PageContent creations on apphook pages, ensuring URL patterns are reloaded immediately when new language variants are added and preventing NoReverseMatch errors, while maintaining backward compatibility and minimal performance impact.

Sequence diagram for PageContent creation triggering URL reload

sequenceDiagram
participant D as "Django ORM"
participant S as "Signal Handler (handle_pagecontent_post_save)"
participant P as "PageContent Instance"
participant M as "ApphookReloadMiddleware"

D->>S: post_save(PageContent, created=True)
S->>P: Check if page has apphook
alt Page has apphook
    S->>M: set_restart_trigger()
end
Loading

Class diagram for new PageContent signal handler integration

classDiagram
class PageContent {
  +page: Page
  +language: str
}
class handle_pagecontent_post_save {
  +post_save(sender, instance, created, **kwargs)
}
PageContent <.. handle_pagecontent_post_save : post_save signal
class ApphookReloadMiddleware {
  +set_restart_trigger()
}
handle_pagecontent_post_save --> ApphookReloadMiddleware : calls set_restart_trigger()
Loading

File-Level Changes

Change Details Files
Add signal handler to trigger URL reload on new PageContent creation for apphook pages
  • Implement post_save receiver that checks for created PageContent and instance.page.application_urls
  • Invoke set_restart_trigger() when a new language variant is created for an apphook page
  • Log debug information about the reload trigger
cms/signals/pagecontent.py
Register new signal handler
  • Import the new pagecontent signal module in the signals package init
cms/signals/__init__.py
Add test suite for apphook reload on language variant operations
  • Create tests to verify URL revision changes when adding variants to apphook pages
  • Ensure no reload occurs for non-apphook pages or content updates
  • Mock set_restart_trigger to assert signal handler calls
cms/tests/test_apphook_reload_language_variants.py

Assessment against linked issues

Issue Objective Addressed Explanation
#8357 Fix the bug where creating a new language variant for a page with an apphook does not reload URL patterns, resulting in django.urls.exceptions.NoReverseMatch until server restart.
#8357 Ensure that the ApphookReloadMiddleware (or equivalent mechanism) triggers a URL reload when a new language variant is created for a page with an apphook.
#8357 Add tests to verify that URL reloading is triggered only for apphook pages and only on creation of new language variants, not on updates or for non-apphook pages.

Possibly linked issues


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Hey there - I've reviewed your changes and they look great!

Prompt for AI Agents
Please address the comments from this code review:

## Individual Comments

### Comment 1
<location> `cms/tests/test_apphook_reload_language_variants.py:24-25` </location>
<code_context>
+        if m != 'cms.middleware.utils.ApphookReloadMiddleware'
+    ]
+)
+class ApphookReloadLanguageVariantTests(CMSTestCase):
+    """Test that URL reloading is triggered when creating language variants for apphook pages."""
+
</code_context>

<issue_to_address>
**suggestion (testing):** Suggestion to add a test for simultaneous creation of multiple language variants.

Add a test that creates multiple language variants in rapid succession for the same apphook page to verify URL reloading handles concurrent updates without race conditions.

```suggestion
class ApphookReloadLanguageVariantTests(CMSTestCase):
    """Test that URL reloading is triggered when creating language variants for apphook pages."""

    def test_simultaneous_creation_of_multiple_language_variants(self):
        """
        Test that creating multiple language variants in rapid succession for the same apphook page
        triggers URL reloading correctly and does not cause race conditions.
        """
        from django.utils import translation

        # Create the initial apphook page in the default language
        page = create_page(
            title="Apphook Page",
            template="INHERIT",
            language="en",
            apphook=SampleApp.__name__,
            published=True,
        )

        # List of languages to add as variants
        languages = ["fr", "de", "it", "es"]

        # Patch UrlconfRevision to monitor reloads
        with patch("cms.middleware.utils.ApphookReloadMiddleware.reload_urlconf") as mock_reload:
            # Create language variants in rapid succession
            for lang in languages:
                with translation.override(lang):
                    create_page_content(
                        language=lang,
                        page=page,
                        title=f"Apphook Page {lang}",
                    )

            # Assert reload_urlconf was called for each new variant
            self.assertEqual(mock_reload.call_count, len(languages))

            # Optionally, check that no exceptions were raised and all variants exist
            for lang in languages:
                self.assertTrue(page.title_set.filter(language=lang).exists())
```
</issue_to_address>

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@Aaditya1273 Aaditya1273 changed the title Fix ApphookReloadMiddleware not handling new language variants fix: Fix ApphookReloadMiddleware not handling new language variants Oct 15, 2025
@fsbraun
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fsbraun commented Oct 16, 2025

@Aaditya1273 Could you please run ruff check cms menus locally and fix any issues?

from cms.models import UrlconfRevision
from cms.test_utils.testcases import CMSTestCase
from cms.test_utils.project.sampleapp.cms_apps import SampleApp
from cms.utils.setup import apphooks
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This import is causing all the tests to fail.

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[BUG] ApphookReloadMiddleware not handling new languages causing reverse exception

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