Fix 9 production error patterns with tests (~100K+ events)

[cursor]

Addresses 9 high-impact production error patterns identified through code audit. None of these fixes from previous closed PRs (#3196, #3199, #3209) were merged.

Fixes

1. OpenAlex license extraction AttributeError (~67K events)

• primary_location.get("source", {}).get("display_name") fails when source is explicitly null
• Fix: Use isinstance(source, dict) guard before accessing nested fields

2. Author MultipleObjectsReturned (~35K events)

• Author.objects.update_or_create(openalex_ids=...) raises when duplicate authors exist
• Fix: Replace with filter().first() + manual update/create pattern

3. OpenAlex util AttributeError on null dict chains

• Multiple .get("key", {}).get(...) patterns fail when values are explicitly null
• Fix: Use (x or {}) pattern; guard against empty display_name causing IndexError

4. Persona webhook AttributeError on .lower()

• _get_nested_attr(...).lower() crashes when status path returns None
• Fix: Add null safety with (raw_status or "").lower() and defaults for all fields

5. "Some authors not found" Sentry noise

• log_error(ValueError(...)) sends to Sentry for a non-actionable condition
• Fix: Downgrade to logger.warning

6. UserDocument BulkIndexError from dynamic mapping

• Bare ObjectField() causes OpenSearch mapping conflicts for headline
• Fix: Add explicit properties (id, headline, profile_image)

7. PersonDocument mapper_parsing_exception

• Non-string headline values cause OpenSearch indexing failures
• Fix: Add prepare_headline normalizer that returns empty string for non-strings

8. Contribution views NoneType error

• hypothesis model no longer exists but is still in allowed models list
• Fix: Remove from _get_allowed_models()

9. Search indexing BulkIndexError / NotFoundError

• Delete not_found errors in bulk operations crash celery tasks
• Fix: Catch NotFoundError and benign BulkIndexError patterns

Tests added

• 6 tests for license extraction null safety
• 7 tests for openalex_util null safety
• 4 tests for Persona webhook null safety
• 4 tests for PersonDocument headline normalizer
• 6 tests for search celery error handling (including _is_benign_bulk_error)

  

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 87.87879% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.79%. Comparing base (ce7eedb) to head (250ee5d).

Files with missing lines	Patch %	Lines
src/search/celery.py	66.66%	6 Missing ⚠️
src/paper/openalex_util.py	95.83%	1 Missing ⚠️
src/paper/views/paper_views.py	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3225      +/-   ##
==========================================
+ Coverage   78.75%   78.79%   +0.03%     
==========================================
  Files         610      610              
  Lines       34334    34379      +45     
==========================================
+ Hits        27039    27088      +49     
+ Misses       7295     7291       -4     

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