Protect NetCDF saving from bad Python-vs-HDF file lock timing #6760
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Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #6760 +/- ##
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+ Coverage 90.25% 90.30% +0.05%
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Files 91 91
Lines 24630 24682 +52
Branches 4609 4625 +16
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+ Hits 22229 22290 +61
+ Misses 1624 1620 -4
+ Partials 777 772 -5 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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trexfeathers
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Oct 27, 2025
lib/iris/tests/unit/fileformats/netcdf/_thread_safe_nc/test_NetCDFWriteProxy.py
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HGWright
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Oct 30, 2025
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Thanks @trexfeathers, for the investigation and then quick turnaround on the fix for this. Just 1 comment added for future clarification. Feel free to add any more to that comment if you think its needed.
trexfeathers
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Oct 30, 2025
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Thanks @HGWright! |
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🚀 Pull Request
Description
Thanks to @RachelNorth and @TeresaHughes for reporting this.
Even when our NetCDF save operations are fully serialised - no parallelism - HDF still occasionally fails to acquire the file. This is despite all Python locks being available at expected moments, and the file reporting as closed. During testing, 2nd retry always succeeded. This is likely caused by HDF-level locking running on a different timescale to Python-level locking - i.e. sometimes Python has released its locks but HDF still has not. Thought to be filesystem-dependent; further investigation is needed but time is limited at the moment so it seemed best to just get the protective code in immediately.
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