feat: use relative frame filenames

[hpouillot]

💡 Motivation and Context

Use project-relative stack frame filename values while keeping the raw path in abs_path. Cymbal uses filename as the source path for Ruby raw frames, so this keeps fingerprints stable across deploy directories without dropping the original absolute path.

Stacked on #213.
Fixes: #212

💚 How did you test it?

Not run successfully locally. bundle exec rspec spec/posthog/exception_capture_spec.rb spec/posthog/client_spec.rb spec/posthog/rails/exception_mechanism_spec.rb failed because the rspec executable is not installed in the local bundle.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran pnpm changeset to generate a changeset file

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Implemented with Pi. This follow-up PR keeps the path-stabilization changes separate from the exception-chain work and aligns Ruby raw frame payloads with Cymbal's filename/abs_path expectations.

[github-actions]

posthog-ruby Compliance Report

Date: 2026-07-03 12:09:00 UTC
Duration: 98647ms

✅ All Tests Passed!

46/46 tests passed

---

Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	110ms
Format Validation.Event Has Uuid	✅	107ms
Format Validation.Event Has Lib Properties	✅	110ms
Format Validation.Distinct Id Is String	✅	106ms
Format Validation.Token Is Present	✅	107ms
Format Validation.Custom Properties Preserved	✅	107ms
Format Validation.Event Has Timestamp	✅	107ms
Retry Behavior.Retries On 503	✅	5407ms
Retry Behavior.Does Not Retry On 400	✅	2110ms
Retry Behavior.Does Not Retry On 401	✅	2110ms
Retry Behavior.Respects Retry After Header	✅	8117ms
Retry Behavior.Implements Backoff	✅	15716ms
Retry Behavior.Retries On 500	✅	5212ms
Retry Behavior.Retries On 502	✅	5212ms
Retry Behavior.Retries On 504	✅	5212ms
Retry Behavior.Max Retries Respected	✅	15621ms
Deduplication.Generates Unique Uuids	✅	113ms
Deduplication.Preserves Uuid On Retry	✅	5211ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10418ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5215ms
Deduplication.No Duplicate Events In Batch	✅	112ms
Deduplication.Different Events Have Different Uuids	✅	108ms
Compression.Sends Gzip When Enabled	✅	107ms
Batch Format.Uses Proper Batch Structure	✅	107ms
Batch Format.Flush With No Events Sends Nothing	✅	5ms
Batch Format.Multiple Events Batched Together	✅	110ms
Error Handling.Does Not Retry On 403	✅	2108ms
Error Handling.Does Not Retry On 413	✅	2107ms
Error Handling.Retries On 408	✅	5210ms

Feature_Flags Tests

✅ 17/17 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	108ms
Request Payload.Flags Request Uses V2 Query Param	✅	106ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	107ms
Request Payload.Flags Request Omits Authorization Header	✅	107ms
Request Payload.Token In Flags Body Matches Init	✅	108ms
Request Payload.Groups Round Trip	✅	107ms
Request Payload.Groups Default To Empty Object	✅	108ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	108ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	107ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	107ms
Request Lifecycle.No Flags Request On Init Alone	✅	3ms
Request Lifecycle.No Flags Request On Normal Capture	✅	106ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	110ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	106ms
Retry Behavior.Retries Flags On 502	✅	210ms
Retry Behavior.Retries Flags On 504	✅	210ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	109ms

[greptile-apps]

Comments Outside Diff (1)

1. spec/posthog/exception_capture_spec.rb, line 10-20 (link)

   First test relies on an implicit environmental assumption

   This test calls parse_backtrace_line without an explicit project_root:, so the method defaults to Dir.pwd. The assertion expect(frame['filename']).to eq('user.rb') holds only because Dir.pwd (the test runner's working directory) doesn't happen to equal /path/to/project. If tests were ever run from that exact directory, frame_filename would return 'app/models/user.rb' instead and the test would silently fail. Pass project_root: '/some/other/root' explicitly to make the assertion deterministic.

_{Reviews (1): Last reviewed commit: "feat: use relative frame filenames" | Re-trigger Greptile}