Alpine Linux: pip and uv fail to install kson-lang 0.1.0 from PyPI

[AndydeCleyre]

Hi, and thanks!

I've been unable to install the PyPI package. Here are some reproducers:

EDIT: I mistakenly thought kson was the right PyPI package, but it's kson-lang. The following is irrelevant.

Oops, wrong package

uv

$ podman run -it --rm ghcr.io/astral-sh/uv:python3.13-alpine sh
/ # uv venv
Using CPython 3.13.7 interpreter at: /usr/local/bin/python
Creating virtual environment at: .venv
/ # uv pip install kson
  x Failed to build `kson==0.1.0`
  |-> The build backend returned an error
  `-> Call to `setuptools.build_meta:__legacy__.build_wheel` failed (exit status: 1)

      [stderr]
      Traceback (most recent call last):
        File "<string>", line 14, in <module>
          requires = get_requires_for_build({})
        File "/root/.cache/uv/builds-v0/.tmpYc8MX4/lib/python3.13/site-packages/setuptools/build_meta.py", line 331, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=[])
                 ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/root/.cache/uv/builds-v0/.tmpYc8MX4/lib/python3.13/site-packages/setuptools/build_meta.py", line 301, in _get_build_requires
          self.run_setup()
          ~~~~~~~~~~~~~~^^
        File "/root/.cache/uv/builds-v0/.tmpYc8MX4/lib/python3.13/site-packages/setuptools/build_meta.py", line 512, in run_setup
          super().run_setup(setup_script=setup_script)
          ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/root/.cache/uv/builds-v0/.tmpYc8MX4/lib/python3.13/site-packages/setuptools/build_meta.py", line 317, in run_setup
          exec(code, locals())
          ~~~~^^^^^^^^^^^^^^^^
        File "<string>", line 14, in <module>
          requires = get_requires_for_build({})
                           ~~~~~~~~~~~~~~~~^^^^
        File "<string>", line 7, in read
      FileNotFoundError: [Errno 2] No such file or directory: '/root/.cache/uv/sdists-v9/pypi/kson/0.1.0/BPvJBWn8kfvrQ9hn9ZReC/src/../README.md'

      hint: This usually indicates a problem with the package or the build environment.

Same result with Python 3.12.

pip

$ podman run -it --rm python:3.13-alpine sh
/ # python -m venv venv
/ # . ./venv/bin/activate
(venv) / # pip install kson
Collecting kson
  Downloading kson-0.1.0.tar.gz (9.4 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  error: subprocess-exited-with-error

  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [24 lines of output]
      Traceback (most recent call last):
        File "/venv/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 389, in <module>
          main()
          ~~~~^^
        File "/venv/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 373, in main
          json_out["return_val"] = hook(**hook_input["kwargs"])
                                   ~~~~^^^^^^^^^^^^^^^^^^^^^^^^
        File "/venv/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 143, in get_requires_for_build_wheel
          return hook(config_settings)
        File "/tmp/pip-build-env-wel7394e/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 331, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=[])
                 ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-wel7394e/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 301, in _get_build_requires
          self.run_setup()
          ~~~~~~~~~~~~~~^^
        File "/tmp/pip-build-env-wel7394e/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 512, in run_setup
          super().run_setup(setup_script=setup_script)
          ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-wel7394e/overlay/lib/python3.13/site-packages/setuptools/build_meta.py", line 317, in run_setup
          exec(code, locals())
          ~~~~^^^^^^^^^^^^^^^^
        File "<string>", line 14, in <module>
        File "<string>", line 7, in read
      FileNotFoundError: [Errno 2] No such file or directory: '/tmp/pip-install-oge_6neb/kson_e47a437f184e4f919ec8266547a624af/../README.md'
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× Getting requirements to build wheel did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

Again, same result for Python 3.12.

EDIT: OK here's the problem with the actually correct package:

Install kson-lang in ghcr.io/astral-sh/uv:python3.13-alpine

$ podman run -it --rm ghcr.io/astral-sh/uv:python3.13-alpine sh
Trying to pull ghcr.io/astral-sh/uv:python3.13-alpine...
Getting image source signatures
Copying blob c987cde7f297 done   |
Copying blob 9d08fbafb11c done   |
Copying blob 5eb8a9c59764 done   |
Copying blob 9824c27679d3 done   |
Copying blob ea971c774474 done   |
Copying config 67581b053f done   |
Writing manifest to image destination
/ # uv venv
Using CPython 3.13.7 interpreter at: /usr/local/bin/python
Creating virtual environment at: .venv
/ # uv pip install kson-lang
Resolved 3 packages in 469ms
  x Failed to build `kson-lang==0.1.0`
  |-> The build backend returned an error
  `-> Call to `build_backend.build_wheel` failed (exit status: 1)

      [stdout]
      Building native artifacts with bundled Gradle setup...
      Gradle build failed:
      ./gradlew: exec: line 340:
      /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/bin/java:
      not found


      [stderr]
      Traceback (most recent call last):
        File "<string>", line 11, in <module>
          wheel_filename = backend.build_wheel("/root/.cache/uv/builds-v0/.tmpi1gAEr", {}, None)
        File "/root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/build_backend.py", line 80, in build_wheel
          _ensure_native_artifacts()
          ~~~~~~~~~~~~~~~~~~~~~~~~^^
        File "/root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/build_backend.py", line 40, in _ensure_native_artifacts
          raise RuntimeError("Failed to build native artifacts")
      RuntimeError: Failed to build native artifacts

      hint: This usually indicates a problem with the package or the build environment.

It seems there are additional build requirements when installing from PyPI which aren't specified on the PyPI page.

[aochagavia]

It seems like you are trying to install a different package (kson) instead of ours (kson-lang). However, even after fixing the package name, installing the library fails:

$ docker run -it --rm ghcr.io/astral-sh/uv:python3.13-alpine sh
/ # uv venv
Using CPython 3.13.7 interpreter at: /usr/local/bin/python
Creating virtual environment at: .venv
/ # uv pip install kson-lang
Resolved 3 packages in 877ms
  x Failed to build `kson-lang==0.1.0`
  |-> The build backend returned an error
  `-> Call to `build_backend.build_wheel` failed (exit status: 1)

      [stdout]
      Building native artifacts with bundled Gradle setup...
      Gradle build failed:
      ./gradlew: exec: line 340:
      /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/nrSCBW9MJ6SoROMhCaUCl/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/bin/java:
      not found


      [stderr]
      Traceback (most recent call last):
        File "<string>", line 11, in <module>
          wheel_filename = backend.build_wheel("/root/.cache/uv/builds-v0/.tmpNGm3Md", {}, None)
        File "/root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/nrSCBW9MJ6SoROMhCaUCl/src/build_backend.py", line 80,
      in build_wheel
          _ensure_native_artifacts()
          ~~~~~~~~~~~~~~~~~~~~~~~~^^
        File "/root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/nrSCBW9MJ6SoROMhCaUCl/src/build_backend.py", line 40,
      in _ensure_native_artifacts
          raise RuntimeError("Failed to build native artifacts")
      RuntimeError: Failed to build native artifacts

      hint: This usually indicates a problem with the package or the build environment.

[aochagavia]

As far as I can see, there are two issues here:

1. We don't ship python wheels for Linux distributions that use musl instead of glibc.
2. Our build system fails when trying to build from source (not sure if this is applies to all builds, or merely builds in musl-based Linux).

[aochagavia]

@AndydeCleyre Not sure what the root cause is of the failure to build from source. Do you feel like investigating? Any info is welcome, even if you don't have time for a full patch.

While this gets fixed, a workaround is to use a different Linux distro:

$ docker run -it --rm ghcr.io/astral-sh/uv:python3.13-trixie sh
# uv venv
Using CPython 3.13.7 interpreter at: /usr/local/bin/python
Creating virtual environment at: .venv
# uv pip install kson-lang
Resolved 3 packages in 322ms
Prepared 3 packages in 315ms
Installed 3 packages in 5ms
 + cffi==2.0.0
 + kson-lang==0.1.0
 + pycparser==2.23

[AndydeCleyre]

It seems like you are trying to install a different package (kson) instead of ours (kson-lang).

Whoops! Wow, whoops. Thanks. I've edited the initial report.

I don't know what kind of binary-bundling you've got going on -- is a pre-built java included in the process?

# ldd /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/bin/java
        /lib64/ld-linux-x86-64.so.2 (0x7fa242768000)
        libjli.so => /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/bin/../lib/libjli.so (0x7fa24273f000)
        libpthread.so.0 => /lib64/ld-linux-x86-64.so.2 (0x7fa242768000)
        libdl.so.2 => /lib64/ld-linux-x86-64.so.2 (0x7fa242768000)
        libc.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7fa242768000)
Error relocating /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/bin/../lib/libjli.so: __strdup: symbol not found
Error relocating /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/mvaokqzVFQNtlTkih2iCu/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/bin/../lib/libjli.so: __rawmemchr: symbol not found

[aochagavia]

In theory, the build should automatically download all necessary dependencies, including a compatible JVM. Somehow this doesn't work properly on Alpine.

All this fiddling with binaries really has me thinking whether we'd be better off having a single platform-independent wheel that relies on a WASM binary...

[AndydeCleyre]

I got a little further after installing gcompat:

      Building native artifacts with bundled Gradle setup...
      Gradle build failed:
      Error: dl failure on line 542
      Error: failed /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/_AnEJaOw_xhT1zgJex7s9/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/lib/server/libjvm.so, because
      Error relocating /root/.cache/uv/sdists-v9/pypi/kson-lang/0.1.0/_AnEJaOw_xhT1zgJex7s9/src/kson-sdist/gradle/jdk/OpenJDK17U-jdk_x64_linux_hotspot_17.0.14_7-a3ebc3/jdk-17.0.14+7/lib/server/libjvm.so:
      posix_fallocate64: symbol not found

And yeah the 64-named libs aren't suitable for musl these days.

Relevant discussion: pypy/pypy#5071

[AndydeCleyre]

Is there any more documentation for the Python library than the to-JSON example? I was looking for something like load and dump methods to convert from and to Python dictionaries and lists.

[holodorum]

I don't know what kind of binary-bundling you've got going on -- is a pre-built java included in the process?

Yes, to be self-contained we install a JDK when building the project. Currently the urls which we install from are set in jdk.properties.

To your second question. The best way to go about that now is to go through json. Something like:

from kson import Kson, FormattingStyle, FormatOptions, IndentType

def loads(kson_input: str) -> dict:
    """Parse KSON string to Python dict"""
    result = Kson.to_json(kson_input)
    return json.loads(result.output())


def dumps(data: dict) -> str:
    """Convert Python dict to KSON string"""
    json_string = json.dumps(data)
    return Kson.format(json_string, FormatOptions(IndentType.Spaces(2), FormattingStyle.PLAIN))

[aochagavia]

Hmm I can't find docs anywhere, so I guess that's still a work in progress (@holodorum / @dmarcotte correct me if I'm wrong).

As for loading / dumping methods, the current release is intentionally as minimal as possible. The best path to load / dump at the moment is to go through existing JSON functions:

• For loading: transform the KSON document to JSON, then load the JSON into a Python object.
• For dumping: transform the Python object to JSON, then parse it as KSON and reformat it.

It's not what I'd call a pretty UX, but it's what we have for now.

Btw if you have more questions / remarks that are unrelated to this issue, I'd love to discuss them further in our Zulip.

[aochagavia]

For clarity, the fix for this issue is twofold:

1. Ensure we download a musl-based JDK when building on a musl-based Linux distro
2. Bonus: provide musllinux wheels for our python bindings (see PEP 656 for details)

[holodorum]

Investigated the issue and it turns out to be a bit harder than expected. Adding the correct JDK in the jdk.properties file allows us to use the JDK on Alpine Linux. However, this doesn't solve the issue completely. The issue seems to be that Kotlin MPP does not support compilation to Native on musl based distributions. There is a 5 year old ticket discussing the same problem. For now it seems that Linux distributions that use musl instead of glibc are not supported.

It seems to be that a solution might lie in configuring the linkerOpts as discussed in this ticket. At the same time, I've tried a few and none of them worked. Possibly there is a workaround like that but it seems to be just 'experimenting' (see this comment).

[AndydeCleyre]

Thanks for looking into it. Maybe someday there will be more python-native python package for kson.

[aochagavia]

This is unfortunate... It surprises me that Kotlin Multiplatform doesn't support Alpine, given that it's reasonably common (all programming languages I actively work with support musl-based distros, including Alpine). I hope we can find a solution to get our existing code running on Alpine. I'll be thinking about it.

@AndydeCleyre out of curiosity, is there any reason you need Alpine instead of something like Debian slim?