fix: show_placeholder did not respect edit/preview mode and failed loudly #8272

fsbraun · 2025-06-30T06:09:46Z

Description

This PR fixes #8271, by

letting the {% show_placeholder %} tag fail silently if the targeted page does not have a content object in the required language
respecting page content objects only visible in the admin in edit and preview mode

Related resources

Checklist

I have opened this pull request against main
I have added or modified the tests when changing logic
I have followed the conventional commits guidelines to add meaningful information into the changelog
I have read the contribution guidelines and I have joined the channel #pr-reviews on our Discord Server to find a “pr review buddy” who is going to review my pull request.

Summary by Sourcery

Enable show_placeholder to respect edit/preview modes by including admin-only content and to handle missing content gracefully outside debug mode.

Bug Fixes:

Ensure show_placeholder silently returns an empty string in production mode when the requested page content or placeholder is missing.
Include page content objects only visible in the admin when rendering placeholders in edit and preview modes.

Enhancements:

Add an admin_manager parameter to Page.get_placeholders for fetching admin-managed content.
Remove redundant content permission checks from admin utils.

Tests:

Add tests for show_placeholder behavior in debug vs non-debug settings and for missing page content.

sourcery-ai · 2025-06-30T06:09:52Z

Reviewer's Guide

This PR updates the show_placeholder tag to fail silently for missing page content in production and to respect admin-only content visibility in edit and preview modes by introducing an admin_manager flag in get_placeholders, adds tests for these behaviors, and cleans up obsolete admin utility code.

Sequence diagram for show_placeholder tag with admin/preview mode handling

sequenceDiagram
    participant User as actor User
    participant Template as Template Engine
    participant CMS as CMS Tags
    participant Page as Page Model
    participant PC as PageContent
    participant PH as Placeholder
    participant Toolbar as Toolbar

    User->>Template: Render template with {% show_placeholder %}
    Template->>CMS: _show_placeholder_by_id(...)
    CMS->>Toolbar: get_toolbar_from_request(request)
    CMS->>Toolbar: Check edit_mode_active/preview_mode_active
    CMS->>Page: get_placeholders(lang, admin_manager)
    alt admin_manager is True
        Page->>PC: PageContent.admin_manager.latest_content().get(...)
    else admin_manager is False
        Page->>PC: PageContent.objects.get(...)
    end
    Page->>PH: Placeholder.objects.get_for_obj(page_content)
    CMS->>Template: Return placeholder content or "" if not found

Class diagram for updated get_placeholders method in Page model

classDiagram
    class Page {
        +get_placeholders(language: str, admin_manager: bool = False) QuerySet
    }
    class PageContent {
        +admin_manager
        +objects
    }
    class Placeholder {
        +get_for_obj(obj)
    }
    Page --> PageContent : uses
    Page --> Placeholder : uses
    PageContent <|-- admin_manager
    PageContent <|-- objects

Class diagram for _show_placeholder_by_id logic update

classDiagram
    class CMS_Tags {
        +_show_placeholder_by_id(context, placeholder_name, reverse_id, lang=None, site=None)
    }
    class Toolbar {
        +edit_mode_active
        +preview_mode_active
    }
    CMS_Tags --> Toolbar : checks mode
    CMS_Tags --> Page : calls get_placeholders
    CMS_Tags --> Placeholder : gets placeholder
    CMS_Tags ..> settings : uses DEBUG
    CMS_Tags ..> PageContent : handles DoesNotExist exception

File-Level Changes

Change	Details	Files
Enhance show_placeholder tag to respect edit/preview modes and silent-fail in production	Determine admin_manager flag from toolbar.edit_mode_active or preview_mode_active Pass admin_manager to get_placeholders call Catch PageContent.DoesNotExist alongside PlaceholderModel.DoesNotExist and return "" when DEBUG is False	`cms/templatetags/cms_tags.py`
Extend get_placeholders API with admin_manager parameter	Add admin_manager boolean parameter with type annotation Use PageContent.admin_manager.latest_content() branch when admin_manager is True Fall back to default PageContent.objects.get when admin_manager is False	`cms/models/pagemodel.py`
Add tests covering fallback and exception paths of show_placeholder	Test that DEBUG=True raises PageContent.DoesNotExist for missing content Test that DEBUG=False returns empty string instead of raising Implement test_show_placeholder_for_page_content_does_not_exist in templatetags tests	`cms/tests/test_templatetags.py`
Remove dead can_change_content logic from admin form utilities	Delete conditional block disabling content fields based on can_change_content Clean up related unused imports in admin/utils	`cms/admin/utils.py`

Assessment against linked issues

Issue	Objective	Addressed	Explanation
#8271	Prevent `PageContent.DoesNotExist` exception when creating the first page with `show_placeholder` tag.	✅
#8271	Ensure `show_placeholder` tag respects edit/preview mode.	✅

Possibly linked issues

[BUG] PageContent.DoesNotExist on first page via show_placeholder #8271: The PR fixes the PageContent.DoesNotExist error in show_placeholder by catching the exception and improving placeholder retrieval logic in admin/preview mode.

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sourcery-ai

Hey @fsbraun - 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_templatetags.py:304` </location>
<code_context>
+            content = _show_placeholder_by_id(context, "does_not_exist", "myreverseid", lang="go-lang")
+            self.assertEqual(content, "")
+
+    def test_show_placeholder_for_page_content_does_not_exist(self):
+        """
+        Verify ``show_placeholder`` correctly handles being given an
+        invalid identifier.
+        """
</code_context>

<issue_to_address>
Potential duplicate or incomplete test for missing page content.

Please implement 'test_show_placeholder_for_page_content_does_not_exist' to cover missing page content in both DEBUG and non-DEBUG modes, ensuring the new error handling is tested.
</issue_to_address>

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cms/tests/test_templatetags.py

vinitkumar

LGTM

…udly (#8272) * fix: show_placeholder tag * Add test * Use current_content * fix: test names switched * Better naming inside test * fix: docs * Update docs/requirements.txt * Fix django_settings for docs

…udly (#8272) (#8274) * fix: show_placeholder tag * Add test * Use current_content * fix: test names switched * Better naming inside test * fix: docs * Update docs/requirements.txt * Fix django_settings for docs

…udly (#8273) * fix: show_placeholder did not respect edit/preview mode and failed loudly (#8272) * fix: show_placeholder tag * Add test * Use current_content * fix: test names switched * Better naming inside test * fix: docs * Update docs/requirements.txt * Fix django_settings for docs * Update package.json

fsbraun added 2 commits June 30, 2025 08:00

fix: show_placeholder tag

e366a30

Add test

bd1595a

sourcery-ai bot reviewed Jun 30, 2025

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cms/tests/test_templatetags.py Outdated Show resolved Hide resolved

Use current_content

908cb9e

fsbraun mentioned this pull request Jun 30, 2025

[BUG] PageContent.DoesNotExist on first page via show_placeholder #8271

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2 tasks

fsbraun added 5 commits June 30, 2025 08:16

fix: test names switched

2d8f45c

Better naming inside test

9f8f2e1

fix: docs

97037d6

Update docs/requirements.txt

23b8f78

Fix django_settings for docs

8b59725

fsbraun requested a review from vinitkumar June 30, 2025 09:37

Merge branch 'main' into fix/show_placeholder

efc6827

vinitkumar approved these changes Jun 30, 2025

View reviewed changes

fsbraun merged commit b2c9b97 into main Jun 30, 2025
65 checks passed

fsbraun deleted the fix/show_placeholder branch June 30, 2025 10:04

fsbraun mentioned this pull request Jun 30, 2025

fix: show_placeholder did not respect edit/preview mode and failed loudly #8273

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fix: show_placeholder did not respect edit/preview mode and failed loudly #8272

fix: show_placeholder did not respect edit/preview mode and failed loudly #8272

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fsbraun commented Jun 30, 2025 •

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fix: show_placeholder did not respect edit/preview mode and failed loudly #8272

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fsbraun commented Jun 30, 2025 • edited by sourcery-ai bot Loading Uh oh! There was an error while loading. Please reload this page.

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Description

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Reviewer's Guide

Sequence diagram for show_placeholder tag with admin/preview mode handling

Class diagram for updated get_placeholders method in Page model

Class diagram for _show_placeholder_by_id logic update

File-Level Changes

Assessment against linked issues

Possibly linked issues

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fsbraun commented Jun 30, 2025 •

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