Cross compiling abi3 for windows arm failed with v1.7.7+

[kahojyun]

Bug Description

Cannot build abi3 aarch64 Windows wheel on Github Action x86 Windows runner.

A minimal reproduction repo is here. The build succeeds if I remove the abi3-py39 feature or use maturin v1.7.6.

Your maturin version (maturin --version)

1.7.8

Your Python version (python -V)

NA

Your pip version (pip -V)

NA

What bindings you're using

pyo3

Does cargo build work?

• Yes, it works

If on windows, have you checked that you aren't accidentally using unix path (those with the forward slash /)?

• Yes

Steps to Reproduce

https://github.com/kahojyun/winarm64-maturin-1-7-8

https://github.com/kahojyun/winarm64-maturin-1-7-8/actions

[messense]

Probably related to #2333 cc @davidhewitt

[davidhewitt]

On first inspection it looks like maturin is doing the right thing, so I've opened PyO3/pyo3#4773

[kahojyun]

I found that maturin v1.7.6 uses xwin for cross-compiling by default. For maturin v1.7.8, if I set MATURIN_USE_XWIN to 1 the build succeeds.

[Ousret]

The plot thicken. I think there's more than what appear.

---

Using MATURIN_USE_XWIN does help, but not in every cases. Curiously, It succeed every time, but produced wheel cannot be trusted.

See https://github.com/jawah/wassima/actions/runs/12336830906/job/34429848274

Things that caught my attention:

• ⚠️ Warning: failed to determine the path to python for 't * C:\hostedtoolcache\windows\Python\3.13.0\x64-freethreaded\python3.13t.exe': The filename, directory name, or volume label syntax is incorrect. (os error 123)
• Wheel contain arch amd64 when target is aarch64

⚠️ Warning: CPython 3.13t at C:\hostedtoolcache\windows\Python\3.13.0\x64-freethreaded\python.exe does not yet support abi3 so the build artifacts will be version-specific.
🛠️ Using xwin for cross-compiling to aarch64-pc-windows-msvc
   Compiling pyo3-build-config v0.23.3
   Compiling pyo3-ffi v0.23.3
   Compiling pyo3-macros-backend v0.23.3
   Compiling pyo3 v0.23.3
   Compiling pyo3-macros v0.23.3
   Compiling wassima v1.1.6 (D:\a\wassima\wassima)
    Finished `release` profile [optimized] target(s) in 10.03s
📦 Built wheel for CPython 3.13t to dist\wassima-1.1.6-cp313-cp313t-win_amd64.whl

[kahojyun]

It appears to be a bug in pyo3-build-config, and I have submitted a PR to address it: PyO3/pyo3#4800. As a temporary solution for existing pyo3 versions, set the environment variable PYO3_CROSS to 1.

[Ousret]

As a temporary solution for existing pyo3 versions, set the environment variable PYO3_CROSS to 1.

It does not work unfortunately. See https://github.com/jawah/wassima/actions/runs/12340559151/job/34438218682 for example.

regards,

[kahojyun]

As a temporary solution for existing pyo3 versions, set the environment variable PYO3_CROSS to 1.

It does not work unfortunately. See jawah/wassima/actions/runs/12340559151/job/34438218682 for example.

regards,

Try enabling generate-import-lib feature in pyo3
https://www.maturin.rs/distribution#cross-compile-to-windows
https://pyo3.rs/main/building-and-distribution#building-abi3-extensions-without-a-python-interpreter

[Ousret]

Better but did go back to same initial result. wheel is invalid.

🍹 Building a mixed python/rust project
🔗 Found pyo3 bindings with abi3 support for Python ≥ 3.7
⚠️  Warning: failed to determine the path to python for `t *       C:\hostedtoolcache\windows\Python\3.13.0\x64-freethreaded\python3.13t.exe`: The filename, directory name, or volume label syntax is incorrect. (os error 123)
🐍 Not using a specific python interpreter (automatically generating windows import library)
📡 Using build options features from pyproject.toml
🛠️ Using xwin for cross-compiling to aarch64-pc-windows-msvc
   Compiling shlex v1.3.0
   Compiling target-lexicon v0.12.16
   Compiling once_cell v1.20.2
   Compiling proc-macro2 v1.0.92
   Compiling cc v1.2.4
   Compiling windows_aarch64_msvc v0.52.6
   Compiling unicode-ident v1.0.14
   Compiling autocfg v1.4.0
   Compiling libc v0.2.168
   Compiling windows-targets v0.52.6
   Compiling heck v0.5.0
   Compiling windows-sys v0.59.0
   Compiling python3-dll-a v0.2.11
   Compiling memoffset v0.9.1
   Compiling quote v1.0.37
   Compiling syn v2.0.90
   Compiling rustls-pki-types v1.10.1
   Compiling pyo3-build-config v0.23.3
   Compiling schannel v0.1.27
   Compiling rustls-pemfile v2.2.0
   Compiling pyo3-macros-backend v0.23.3
   Compiling pyo3-ffi v0.23.3
   Compiling pyo3 v0.23.3
   Compiling indoc v2.0.5
   Compiling cfg-if v1.0.0
   Compiling unindent v0.2.3
   Compiling rustls-native-certs v0.7.3
   Compiling pyo3-macros v0.23.3
   Compiling wassima v1.1.6 (D:\a\wassima\wassima)
    Finished `release` profile [optimized] target(s) in 52.82s
📦 Built wheel for abi3 Python ≥ 3.7 to dist\wassima-1.1.6-cp37-abi3-win_arm64.whl
⚠️ Warning: CPython 3.13t at C:\hostedtoolcache\windows\Python\3.13.0\x64-freethreaded\python.exe does not yet support abi3 so the build artifacts will be version-specific.
🛠️ Using xwin for cross-compiling to aarch64-pc-windows-msvc
   Compiling pyo3-build-config v0.23.3
   Compiling pyo3-macros-backend v0.23.3
   Compiling pyo3-ffi v0.23.3
   Compiling pyo3 v0.23.3
   Compiling pyo3-macros v0.23.3
   Compiling wassima v1.1.6 (D:\a\wassima\wassima)
    Finished `release` profile [optimized] target(s) in 9.68s
📦 Built wheel for CPython 3.13t to dist\wassima-1.1.6-cp313-cp313t-win_amd64.whl

https://github.com/jawah/wassima/actions/runs/12346071103/job/34451209764

and PYO3_CROSS=1 is set.

regards,

[kahojyun]

Better but did go back to same initial result. wheel is invalid.

I forget to mention that MATURIN_USE_XWIN should be unset 🙇. Additionally, it's important to be aware that pyo3 automatically enables cross-compiling mode if the PYO3_CROSS environment variable is present, regardless of its value.

I have another sad news: the combination of the abi3 and generate-import-lib flags seems to fail with pyo3=0.23. I am currently looking into this problem.