Fixed post admin NoReverseMatch error

[hlbmtc]

https://metaculus.sentry.io/issues/7486354619/?referrer=slack&notification_uuid=ea42c107-a752-4cc8-9119-fd3665897a70&environment=prod&alert_rule_id=15420910&alert_type=issue

Summary by CodeRabbit

• Bug Fixes
  • Enhanced validation in the admin interface to ensure certain operations are only available when objects are fully initialized in the database, preventing potential errors with unsaved changes.

[coderabbitai]

📝 Walkthrough

Walkthrough

The update_pseudo_materialized_fields_button method in PostAdmin now validates that the object has a primary key in addition to existing before generating the "Update Cached Fields" admin action link.

Changes

Admin Button Guard Tightening

Layer / File(s)	Summary
Admin button primary key guard posts/admin.py	The update_pseudo_materialized_fields_button method now checks obj.pk in addition to obj existence before rendering the update cached fields link.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

A rabbit hops through Django code,
Finds a guard that was outdated—
Now the button checks both path and key,
No orphaned links will be created! 🐰✨

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: fixing a NoReverseMatch error in the post admin module by adding a primary key check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/admin-post-reverse-error

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[coderabbitai]

🧹 Nitpick comments (1)

posts/admin.py (1)

106-106: ⚡ Quick win

Prefer explicit None checks for clarity.

While the Post model uses BigAutoField (which never generates pk=0), the more explicit obj is None or obj.pk is None is a clearer defensive pattern that makes the intent unmistakable.

Suggested patch

-        if not obj or not obj.pk:
+        if obj is None or obj.pk is None:
             return ""

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@posts/admin.py` at line 106, Replace the truthy check "if not obj or not
obj.pk" with an explicit None check to clarify intent: use "if obj is None or
obj.pk is None" (locate the condition that references the local variable obj
inside the posts/admin.py admin method where object existence is validated) so
the code explicitly checks for missing object or missing primary key rather than
relying on truthiness.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@posts/admin.py`:
- Line 106: Replace the truthy check "if not obj or not obj.pk" with an explicit
None check to clarify intent: use "if obj is None or obj.pk is None" (locate the
condition that references the local variable obj inside the posts/admin.py admin
method where object existence is validated) so the code explicitly checks for
missing object or missing primary key rather than relying on truthiness.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 0c6dd47b-d519-4e69-ae04-683fe863a16e

📥 Commits

Reviewing files that changed from the base of the PR and between 750eb48 and 11efa91.

📒 Files selected for processing (1)

• posts/admin.py

[github-actions]

🚀 Preview Environment

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Resource	Details
🌐 Preview URL	https://metaculus-pr-4736-fix-admin-post-reverse-error-preview.mtcl.cc
📦 Docker Image	ghcr.io/metaculus/metaculus:fix-admin-post-reverse-error-11efa91
🗄️ PostgreSQL	NeonDB branch preview/pr-4736-fix-admin-post-reverse-error
⚡ Redis	Fly Redis mtc-redis-pr-4736-fix-admin-post-reverse-error

Details

• Commit: 0ea80337300724e1806ef3b148c16f2cd6e63d78
• Branch: fix/admin-post-reverse-error
• Fly App: metaculus-pr-4736-fix-admin-post-reverse-error

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