Missing import for cpython · wasmtime

Hi all, I am trying to compile cpython for wasip2 and am getting the following issue when I try and run it with wasmtime:

wasmtime run --wasm max-wasm-stack=8388608 --wasi preview2 --dir {HOST_DIR}::{GUEST_DIR}

Error: failed to run main module `/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/cross-build/wasm32-wasip2/python.wasm`

Caused by:
    0: failed to instantiate "/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/cross-build/wasm32-wasip2/python.wasm"
    1: unknown import: `wasi_snapshot_preview1::adapter_open_badfd` has not been defined
Traceback (most recent call last):
  File "/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/./Tools/wasm/wasi.py", line 365, in <module>
    main()
    ~~~~^^
  File "/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/./Tools/wasm/wasi.py", line 361, in main
    dispatch[context.subcommand](context)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/./Tools/wasm/wasi.py", line 85, in wrapper
    return func(context, working_dir)
  File "/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/./Tools/wasm/wasi.py", line 272, in make_wasi_python
    subprocess.check_call([exec_script, "--version"])
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/python@3.13/3.13.1/Frameworks/Python.framework/Versions/3.13/lib/python3.13/subprocess.py", line 419, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '[PosixPath('/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/cross-build/wasm32-wasip2/python.sh'), '--version']' returned non-zero exit status 1.

I built with wasi-sdk v25 (which might be the issue) and using wasmtime v28 and v29 caused the issue.

If anyone has any ideas, I'd appreciate it, otherwise I'll keep trying different combinations of wasmtime and wasi-sdk. Thanks!

Victor Adossi (Jan 21 2025 at 14:53):

wasm-tools component new fails to resolve wasi_snapshot_preview1 with proxy adapter · Issue #1939 · bytecodealliance/wasm-tools

Hi There, I'm trying to build a component that could be used by wasmtime serve. The code is in Rust, but for various reasons I cannot rely on Cargo and have to work in Bazel. I can build core Wasm ...

Ben Brandt (Jan 21 2025 at 14:54):

Victor Adossi (Jan 21 2025 at 14:56):

Yeah it seems unlikely since the tooling probably isn't doing anything funny with the adapter name/does this properly... but I wonder if this is something that tripped people up somewhat recently, and specifying an adapter name (via --adapt name=<path> might be necessary now where it wasn't before...

Ben Brandt (Jan 21 2025 at 15:03):

it is also possible that while I am telling cpython to compile with the target wasip2 that it is still doing it for p1 and that is also causing an issue...

Joel Dice (Jan 21 2025 at 15:08):

Is the python.wasm file a module or a component (use e.g. wasm-tools print and look at the first line of the output)? If it's a module, then presumably wasm-component-ld is not being run and the adapter isn't being used. Keep in mind that wasm32-wasip2 is not yet a supported target for CPython, so hacks may be required to get it working.

Ben Brandt (Jan 21 2025 at 15:14):

ah it is just a module... Ok this likely explains the issue thanks. I was just trying to check out Brett's flag to try a different target , which doesn't work yet. All good. thanks everyone!

Notification Bot (Jan 21 2025 at 15:14):

Notification Bot (Jan 21 2025 at 15:25):

Ben Brandt (Jan 21 2025 at 15:25):

Checked 112 modules (69 built-in, 0 shared, 26 n/a on wasi-wasm32, 9 disabled, 8 missing, 0 failed on import)
Error: failed to run main module `/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/cross-build/wasm32-wasip1/python.wasm`

Caused by:
    0: failed to instantiate "/Users/benjamin.brandt/github/wasi-wheels/cpython-3.13.1/cross-build/wasm32-wasip1/python.wasm"
    1: unknown import: `wasi_snapshot_preview1::adapter_open_badfd` has not been defined

Ben Brandt (Jan 21 2025 at 15:31):

It also doesn't work with wasi-sdk 24... it is possible there's something wrong with my wasmtime or I messed something up in the build... I'll keep digging

Joel Dice (Jan 21 2025 at 15:45):

Hmm, that definitely shouldn't happen. The only part of wasi-libc that references adapter_open_badfd is descriptor_table.c, which is explicitly excluded from the WASIp1 build. I wonder if files got accidentally cached across the p2 and p1 builds? Maybe try doing a clean build if you haven't already.

Ben Brandt (Jan 21 2025 at 15:58):

I can ask @Brett Cannon again... for some reason it works for him, but I am having issues which leads me to believe I have something weird in my setup. But I guess this is more of a Cpython issue than a wasmtime issue...

Ben Brandt (Jan 21 2025 at 16:12):

I've also cleaned the entire cpython dir and replaced it multiple times but nothing seems to help...

Ralph (Jan 21 2025 at 16:42):

Ben Brandt (Jan 21 2025 at 16:48):

Yeah maybe it is because I am on 3.13.1 and there are changes on main I
need to backport... I'll take a look

Ben Brandt (Jan 21 2025 at 17:08):

@Joel Dice I actually have the same problem with the build from the script in componentize-py... so maybe it has more to do with how we are invoking wasmtime (or my wasmtime is wrong)

Joel Dice (Jan 21 2025 at 17:11):

componentize-py only cares about libpython312.so and simply ignores python.wasm, so the latter could be broken in various ways without me noticing. What's your goal here? Are you planning to use python.wasm for some specific purpose?

Ben Brandt (Jan 21 2025 at 17:25):

It was for building the wheels. And Brett's script does this validation.
But maybe I also only need the .so file and can just ignore it as well.

Stream: wasmtime

Topic: Missing import for cpython

Ben Brandt (Jan 21 2025 at 14:24):