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GeezerVison is showing github.com — gh-148675: Optimize arraydescr structure: use char[3] by vstinner · Pull Request #149455 · python/cpython

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@vstinner

@vstinner vstinner commented May 6, 2026 •
edited by bedevere-app Bot
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Replace "const char *typecode;" with "char typecode[3];" to make the arraydescr structure smaller and avoids an indirection.

  • Issue: Add support for numpy buffer format Zf and Zd #148675

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@vstinner
pythongh-148675: Optimize arraydescr structure: use char[3]
1b52f8c 
Replace "const char *typecode;" with "char typecode[3];" to make the
arraydescr structure smaller and avoids an indirection.
@vstinner vstinner added the skip news label May 6, 2026
@bedevere-app bedevere-app Bot mentioned this pull request May 6, 2026
Add support for numpy buffer format Zf and Zd #148675
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@bedevere-app bedevere-app Bot added the awaiting core review label May 6, 2026
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read-the-docs-community Bot commented May 6, 2026

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Documentation build overview

📚 cpython-previews | 🛠️ Build #32562183 | 📁 Comparing 1b52f8c against main (70e365c)

  🔍 Preview build  

2 files changed
± library/functions.html
± whatsnew/3.15.html
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@vstinner

vstinner commented May 6, 2026

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@scoder @encukou: Would you mind to review this change?
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scoder approved these changes May 6, 2026
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Looks good to me. Enough to change the struct field back to its previous (padded) size.

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@bedevere-app bedevere-app Bot removed the awaiting core review label May 6, 2026
@scoder

scoder commented May 6, 2026

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Personally, I would also have optimised the strcmp() calls into single character comparisons to make it clear to the C compiler that that's almost always enough for taking the decision, but that'd be an optimisation with yet-to-be-measured benefit, not a fix. Definitely not something that comes with a deadline.
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@bedevere-app bedevere-app Bot added the awaiting merge label May 6, 2026
@scoder scoder mentioned this pull request May 6, 2026
Adapt array module declarations Python 3.15 changes cython/cython#7659
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@encukou
encukou merged commit 9274d96 into python:main May 6, 2026
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@bedevere-app bedevere-app Bot removed the awaiting merge label May 6, 2026
@vstinner
vstinner deleted the array_typecode branch May 6, 2026 14:34
@vstinner

vstinner commented May 6, 2026

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Thanks for merging my change @encukou :-)
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@vstinner @scoder @encukou
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