Fix flaky test_merge_dask_different_crs_matches_eager on macOS#1495
Merged
brendancol merged 1 commit intomainfrom May 5, 2026
Merged
Fix flaky test_merge_dask_different_crs_matches_eager on macOS#1495brendancol merged 1 commit intomainfrom
brendancol merged 1 commit intomainfrom
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test_merge_dask_different_crs_matches_eager intermittently SIGABRTs on macOS CI runners. The merge() dask graph creates a fresh pyproj.Transformer per chunk, and PROJ's first-time CRS-database load is not safe under concurrent threaded workers — multiple threads racing to init the SQLite DB on macOS triggers an abort. The test exercises dask graph correctness, not dask threading. Pin it to the synchronous scheduler and pre-warm pyproj.CRS objects so the parity assertion runs without the threading dimension. CRS thread-safety in the production reproject path is its own concern and is not regressed here. Refs the same crash on PR #1492 macOS-3.13 and on main run e253900 (macOS-3.12).
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What
Pin
test_merge_dask_different_crs_matches_eagerto the synchronousdask scheduler and pre-warm the PROJ CRS database before the parity
assertion.
Why
This test SIGABRTs intermittently on macOS CI runners. Same crash
signature on:
Both pin the abort at
xrspatial/tests/test_reproject.py:2460—the
.compute().valuescall that triggers the dask threaded scheduler.The merge dask graph creates a fresh
pyproj.Transformerper chunk.PROJ's first-time CRS-database load is a race when multiple threads
hit the SQLite-backed database at once on macOS. Linux and Windows
typically serialise enough that the race is invisible.
The test asserts dask-graph correctness, not threading correctness.
Synchronous compute exercises the same graph without the threading
dimension. Production reproject thread-safety is a separate concern
and is not regressed here.
Test plan