ref(suspect commits): Simplify event file committers to GroupOwner-only behavior

[nora-shap]

Summary

Removes the legacy release-based fallback logic from the event file committers endpoint, simplifying it to use only GroupOwner-based suspect commit detection.

Current behavior: If there are no suspect commits for the event, do a live analysis using the legacy strategy, do not save any of the commits it finds as suspect, return as many as it finds.

💡 : it was doing this because it was the only way to show a suspect commit if the Author was NOT a User of their org. The legacy strategy does not allow GroupOwner creation if there is not an associated User, it ignores those. This does not match the behavior of the non-legacy strategy, which allows GroupOwners with user=None and all serializers have fallback logic to display details from the CommitAuthor object if there is no User. The legacy method needs to be updated to allow GroupOwners with user=None.

Proposed changes: no live analysis - only GroupOwners created during original analysis will be retuned.

While my intention has been to create fewer but better suspect commits, with the logic in this flow meant I was actually displaying a lot more legacy strategy suspect commits, which is not what I want.

Changes Made

Core Logic Changes

• Removed legacy fallback: get_serialized_event_file_committers now only calls _get_serialized_committers_from_group_owners
• Dynamic suspect commit type: Uses suspectCommitStrategy from GroupOwner context instead of hardcoding INTEGRATION_COMMIT
  • RELEASE_BASED → "via commit in release"
  • SCM_BASED → "via SCM integration"
• Preserved API contract: Still returns 404 when no committers found (not empty array)

Behavior Changes

Before

# 1. Check GroupOwners first
# 2. If no GroupOwners, fall back to release-based analysis (legacy logic)
# 3. Analyze stacktrace frames against recent release commits  
# 4. Always returned "via SCM integration" regardless of actual strategy
# 5. Any number of suspect commits can be returned

After

# 1. Check GroupOwners only - all suspect commit strategies create GroupOwners when the Issue is first processed
# 2. If no GroupOwners, return 404 "No committers found"
# 3. Use actual commit strategy from GroupOwner context
# 4. Only 1 suspect commit can be returned

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/integrations/utils/commit_context.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #98504      +/-   ##
==========================================
- Coverage   81.18%   80.06%   -1.13%     
==========================================
  Files        8544     8549       +5     
  Lines      376576   387896   +11320     
  Branches    23954    23954              
==========================================
+ Hits       305719   310562    +4843     
- Misses      70492    76969    +6477     
  Partials      365      365              

[thetruecpaul]

Looks good overall — please fix the failing tests & typing jobs

[sentry]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ AssertionError: assert '0' in 'Details\n-------\n... in test

• ‼️ AssertionError: assert '6' in 'Details\n-------\n... in test

_{Did you find this useful? React with a 👍 or 👎}