Dependency to orjson breaks compatibility to PyPy

[rkrell]

First Check

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Example Code

pip install fastapi==0.111.0

Description

I use a virtual environment with pypy3.10-7.3.13.

Recently, there has been added a default dependency to orjson.
orson has declared to be incompatible to PyPy see https://pypi.org/project/orjson/:

orjson does not and will not support PyPy.

When running the command
pip install fastapi==0.111.0

I end up in:

...
Building wheels for collected packages: orjson
  Building wheel for orjson (pyproject.toml) ... error
  error: subprocess-exited-with-error
  
  × Building wheel for orjson (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [14 lines of output]
      Running `maturin pep517 build-wheel -i /home/rkrell/.pyenv/versions/pypy3.10-7.3.13/envs/myapi-pypy3.10-7.3.13/bin/python --compatibility off`
      📦 Including license file "/tmp/pip-install-gnxx4czm/orjson_a4021de98489486bb0484abd53cfbaa5/LICENSE-APACHE"
      📦 Including license file "/tmp/pip-install-gnxx4czm/orjson_a4021de98489486bb0484abd53cfbaa5/LICENSE-MIT"
      🍹 Building a mixed python/rust project
      🔗 Found pyo3-ffi bindings
      🐍 Found PyPy 3.10 at /home/rkrell/.pyenv/versions/pypy3.10-7.3.13/envs/myapi-pypy3.10-7.3.13/bin/python
      error: package `associative-cache v2.0.0` cannot be built because it requires rustc 1.65 or newer, while the currently active rustc version is 1.63.0
      Either upgrade to rustc 1.65 or newer, or use
      cargo update -p [email protected] --precise ver
      where `ver` is the latest version of `associative-cache` supporting rustc 1.63.0
      💥 maturin failed
        Caused by: Failed to build a native library through cargo
        Caused by: Cargo build finished with "exit status: 101": `env -u CARGO PYO3_ENVIRONMENT_SIGNATURE="pypy-3.10-64bit" PYO3_PYTHON="/home/rkrell/.pyenv/versions/pypy3.10-7.3.13/envs/myapi-pypy3.10-7.3.13/bin/python" PYTHON_SYS_EXECUTABLE="/home/rkrell/.pyenv/versions/pypy3.10-7.3.13/envs/myapi-pypy3.10-7.3.13/bin/python" "cargo" "rustc" "--message-format" "json-render-diagnostics" "--manifest-path" "/tmp/pip-install-gnxx4czm/orjson_a4021de98489486bb0484abd53cfbaa5/Cargo.toml" "--release" "--lib"`
      Error: command ['maturin', 'pep517', 'build-wheel', '-i', '/home/rkrell/.pyenv/versions/pypy3.10-7.3.13/envs/myapi-pypy3.10-7.3.13/bin/python', '--compatibility', 'off'] returned non-zero exit status 1
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for orjson
Failed to build orjson
ERROR: Could not build wheels for orjson, which is required to install pyproject.toml-based projects

Is fastapi now officially declared to be incompatible to PyPy (although it has been working the whole time) or is there a way to exclude orjson from the requirements for this purpose?

Operating System

Linux

Operating System Details

Debian 12

FastAPI Version

0.111.0

Pydantic Version

2.7.2

Python Version

Python 3.10.13 (f1607341da97ff5a1e93430b6e8c4af0ad1aa019, Sep 28 2023, 05:41:26) [PyPy 7.3.13 with GCC 10.2.1 20210130 (Red Hat 10.2.1-11)]

Additional Context

No response

[Kludex]

An environment marker is needed for PyPy: orjson; platform_python_implementation == 'CPython'.

[rkrell]

Yes, but probably in FastAPI itself. Currently I cannot see any way to prevent orjson from being installed when updating to the latest version of fastapi.

[Kludex]

Yes, but probably in FastAPI itself. Currently I cannot see any way to prevent orjson from being installed when updating to the latest version of fastapi.

Yes, I meant fastapi itself.

[danyd555]

is there already an issue for this ?
only workaround is playing with pip install --no-deps and pip check to install only the packages you want,

[rkrell]

I created a pull request against master for this: #11689
Some checks fail, but this PR should not be the cause as it seems.

I changed the specifier to platform_python_implementation != 'PyPy', to be more specific to this issue and to not exclude other python implementations for now.

[tiangolo]

Thank you!

Given this and another report, I decided to remove orjson and ujson from the default dependencies completely. They are still in the all optional dependencies. But they are no longer included when installing with pip install fastapi.

This is available in FastAPI 0.111.1.

Thanks for letting me know and for the PR! ☕