Fix infinite recursion when storing remote actors with mentions #2369
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When storing remote actors with @mentions in their bios, the mention processing filter would fetch the mentioned actor, which would then process mentions in their bio, creating an infinite loop that fills error logs and crashes with stack overflow. The fix temporarily removes mention/hashtag/link filters around the to_json() call when storing remote actors, then re-adds them afterward. Added comprehensive tests that reproduce the recursion scenario: - Self-mention: actor mentioning themselves in their bio - Cross-mention: two actors mentioning each other The code includes detailed comments documenting this approach's shortcomings and exploring better long-term solutions that distinguish between incoming (storage) and outgoing (federation) contexts.
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Pull Request Overview
This PR fixes an infinite recursion bug that occurs when storing remote actors whose bios contain mentions. The recursion happens because mention processing filters attempt to fetch mentioned actors, which then trigger mention processing on those actors' bios, creating a loop.
Key Changes:
- Temporarily removes mention/hashtag/link filters during
Remote_Actors::prepare_custom_post_type()execution to prevent recursion - Adds comprehensive test coverage for self-mention and cross-mention scenarios
- Documents the problem, current approach, limitations, and proposed long-term architectural improvements
Reviewed Changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| includes/collection/class-remote-actors.php | Implements filter removal/re-addition around to_json() call to prevent recursive mention processing during actor storage |
| tests/phpunit/tests/includes/collection/class-test-remote-actors.php | Adds two new test cases verifying no recursion occurs with self-mentions and cross-mentions in actor bios |
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tests/phpunit/tests/includes/collection/class-test-remote-actors.php
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Instead of using remove_all_filters() which could interfere with other tests, extract filter callbacks into variables and remove them individually using remove_filter(). This ensures only the filters added by these specific tests are removed during cleanup, preventing interference with filters from other test sources.
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Fixes #2366, the infinite recursion bug that fills error logs when storing remote actors with @mentions in their bios.
Proposed changes:
The Problem
When a remote actor's bio contains mentions (e.g.,
@[email protected]), the mention processing filter fetches that mentioned actor, which then processes mentions in their bio, creating an infinite loop that results in stack overflow errors.The Solution
In
Remote_Actors::prepare_custom_post_type(), temporarily remove theactivitypub_activity_object_arrayfilters (Mention, Hashtag, Link) aroundto_json(), then re-add them. This prevents filters from triggering during storage while preserving functionality for outgoing federation.Other information:
test_create_actor_with_self_mention_no_recursiontest_create_actor_with_cross_mentions_no_recursionTesting instructions:
npm run env-test -- --filter=test_create_actor_withnpm run env-testChangelog entry
Changelog Entry Details
Significance
Type
Message
Fix infinite recursion when storing remote actors with mentions in their bios