`anyio` imports break when the app is packaged with PyOxidizer

[ntamas]

Things to check first

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

AnyIO version

4.15.1

Python version

3.10.9 (because PyOxidizer uses this particular version of Python)

What happened?

When an app is packaged with PyOxidizer and it tries to import anyio, the app crashes with the following exception:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "anyio", line 11, in <module>
  File "anyio._lazyimport", line 23, in install_lazy_importer
  File "anyio._lazyimport", line 116, in _build_lazy_map
  File "inspect", line 1285, in getsource
  File "inspect", line 1267, in getsourcelines
  File "inspect", line 1078, in findsource
  File "inspect", line 955, in getsourcefile
  File "inspect", line 916, in getfile
TypeError: <module 'anyio' (<oxidized_importer.OxidizedFinder object at 0x1054d0ac0>)> is a built-in module

This is because PyOxidizer uses an import mechanism that loads the modules directly from the binary of the executable and it does not make the source code of the module available. Contrary to anyio's expectations, it does not throw an OSError when inspect.getsource() fails but a TypeError is thrown instead. This is then ignored by _build_lazy_map() and the exception propagates to the top level. Extending _build_lazy_map() to catch TypeError (or maybe a blanket Exception) around inspect.getsource() would probably solve the problem. Checking getattr(sys, "frozen", False) would also be an alternative to detect PyOxidizer, PyInstaller and many other tools that freeze a Python app into an executable.

How can we reproduce the bug?

Build a simple application with PyOxidizer that attempts to import anyio. Attached is a self-contained ZIP file with the required files; running ./run.sh will create a virtualenv, install PyOxidizer in it from PyPI, then build the executable with PyOxidizer. Besides Python, a Rust compiler is also needed in the environment.

anyio-pyoxidizer-crash-repro.zip

[agronholm]

Prior to releasing v4.15.1, I tested it with PyInstaller and it worked fine. TypeError is not expected, as AnyIO's modules are not built-ins. That said, the stdlib docs do mention TypeError, so I think we can at least cover that case.

[skulitom]

I reproduced the same TypeError with a subprocess import using a loader that omits file on anyio and anyio.abc. I am preparing a narrow fix to use the existing eager-import fallback for this documented exception, with a regression covering public exports, the deprecated alias, and a working async call. This is a loader-level reproduction, not a PyOxidizer build. Prepared with Codex.