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GeezerVison is showing github.com — fix: guard debug stack walk by windsornguyen · Pull Request #716 · MagicStack/uvloop

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@windsornguyen

@windsornguyen windsornguyen commented Jan 14, 2026

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Summary

Guard uvloop’s debug stack capture on Python 3.14 by walking frames defensively instead of calling traceback.walk_stack() directly. This avoids AttributeError / segfaults when async generator finalization surfaces non‑frame objects (e.g. _asyncio.TaskStepMethWrapper) under debug mode.

Details

  • Replaces traceback.walk_stack() with a simple f_back walk that only includes frames with f_lineno and f_code.
  • Keeps debug stack capture intact while preventing crashes.

Repro (from #715)

Enable debug mode and run an async‑generator chain that finalizes under uvloop:

  • PYTHONASYNCIODEBUG=1
  • Python 3.14 + uvloop 0.22.1

See issue #715 for the minimal script and traceback.

Tests

  • python3 -m pytest

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@windsornguyen
fix: guard debug stack walk
825e943
@windsornguyen windsornguyen mentioned this pull request Jan 14, 2026
uvloop debug mode crashes on Python 3.14 during async generator finalization (traceback.walk_stack sees non-frame object) #715
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windsornguyen added 2 commits January 14, 2026 00:26
@windsornguyen
fix(debug): guard stack extraction
68af9b3
@windsornguyen
fix(debug): lock cb handle counters
f9754da
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@windsornguyen
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