[Gareth.Y (linjiaye929)]

Summary

Logging a BraintrustStream currently postpones copy() until background export. If the application consumes its stream first, the logged output can become None, lose a text prefix, or fail JSON assembly. This also affects a @traced function that returns a stream its caller consumes once.

Capture the logging branch at log time without reading chunks, then resolve it lazily. Keep a fresh per-attempt copy so yielded error chunks and final JSON-assembly errors remain errors on repeated resolution.

Validation

Python 3.12.14, actual SSEClient over in-memory SSE bytes, and the SDK's native memory logger:

• Baseline regressions: 5 failed, 4 passed.
• Fixed regressions: 9 passed.
• Entire test_logger.py, functions/test_stream.py, and test_span_customizer.py: 248 passed, 4 skipped, 21 subtests passed. Skips require optional Pydantic or Python 3.14 t-strings.
• Separate local validation repeated those results and passed 21 supplementary cases.
• Ruff 0.15.21 check/format and git diff --check passed.

Tests run with cassette replay enabled, the Braintrust pytest plugin disabled, and a socket guard rejecting live connections. No live service or provider calls were used. Full nox/core/version-matrix, pylint/type-checker sessions, benchmarks, and make fixup were not run.

Compatibility and limits

• Snapshotting buffers consumed chunks until lazy export can use them. The retry snapshot lasts until its lazy record is released; an unconsumed SSE parsing generator can retain the original stream wrapper until consumption finishes.
• List-backed streams become one-shot at log time rather than first export. Repeating list iteration before export previously worked incidentally; the documented stream contract requires copying before repeated consumption.
• Concurrent readers and synchronous iterators started before logging remain outside this fix. Nested streams in dictionaries retain their existing behavior.
• Retry preservation covers yielded error chunks and final JSON assembly. Invalid JSON inside an SSE text_delta can still terminate the parser and produce None on a later retry, as before.

AI assistance

Prepared with AI assistance, including a separate local review of the reproduction, patch, tests, and compatibility boundaries.

CI status

As checked on 2026-10-13 at 11:03 UTC for head 9f6d44611c2ac07e127fda576f98f558b18c90d9, both upstream workflow runs report completed / action_required:

• checks
• integration-tests

CI has not passed. The local validation above does not represent a successful upstream CI run.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-13T11:10:46.949927Z	9f6d446	Draft marked ready

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