Description

brettcannon

opened on Feb 6, 2026

Issue body actions

cpython/Platforms/WASI/__main__.py

Line 328 in 957f9fe

f"{wasi_build_dir}/build/lib.wasi-wasm32-{python_version}"

That should be reading the directory location from pybuilddir.txt instead.

Linked PRs

• gh-144533: Use pybuilddir.txt to find _sysconfigdata for WASI #144535
• GH-144533: Use wasmtime's --argv0 to auto-discover sysconfig in WASI builds #145328

Activity

1. brettcannon

   added

   buildThe build process and cross-buildThe build process and cross-build

   easy

   3.15bugs and security fixesbugs and security fixes

   on Feb 6, 2026
2. therohityadav

   added 4 commits that reference this issue on Feb 6, 2026

   pythongh-144533: Use pybuilddir.txt to find _sysconfigdata for WASI

   5e55826

   pythongh-144533: Use pybuilddir.txt to find _sysconfigdata for WASI

   035c77e

   pythongh-144533: Use pybuilddir.txt to find _sysconfigdata for WASI

   b64935a

   pythongh-144533: Use pybuilddir.txt to find _sysconfigdata for WASI

   0ecc19e
3. brettcannon

   added

   OS-wasi

   on Feb 12, 2026
4. brettcannon commented on Feb 20, 2026

   

   brettcannon

   on Feb 20, 2026

   MemberAuthor

   More actions

   For posterity, I figured out why this approach was initially taken. The _sysconfigdata module is found via getpath.py which bases it on the location of the source checkout and pybuilddir.txt. Unfortunately, to get imports to work from a checkout we mount the checkout to / in the WASI guest which makes the checkout location recorded via ./configure be incorrect. As such, we need to use PYTHONPATH to manually include the build directory that pybuilddir.txt points at. And since we need to set PYTHONPATH for the host runner when we call ./configure so it ends up in Makefile, we need to calculate the path to the build directory instead of getting to use pybuilddir.txt.

   Reacted by Jaime Andrés Gómez de Luna
5. brettcannon

   changed the title [-]Use `pybuilddir.txt` to find `_sysconfigdata` for the WASI build script[/-] [+]Stop calculating the location of `_sysconfigdata` for the WASI build script[/+] on Feb 20, 2026
6. brettcannon commented on Feb 20, 2026

   

   brettcannon

   on Feb 20, 2026

   MemberAuthor

   More actions

   And Savannah has a better solution outlined in #144535 (comment) .
7. savannahostrowski

   added a commit that references this issue on Feb 28, 2026

   GH-144533: Use wasmtime's --argv0 to auto-discover sysconfig in WASI …

   180d58c
8. savannahostrowski

   closed this as completedon Feb 28, 2026
9. brijkapadia

   added a commit that references this issue on Feb 28, 2026

   pythonGH-144533: Use wasmtime's --argv0 to auto-discover sysconfig in…

   4560c85
10. ljfp

    added a commit that references this issue on Apr 25, 2026

    pythonGH-144533: Use wasmtime's --argv0 to auto-discover sysconfig in…

    9f4be16

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