[WASI] test cases with sys.path.insert(0, os.curdir) fail on WASI#93461
Description
Bug report
Test cases that insert os.curdir ('.') into sys.path fail on WASI platforms. I think it is related how wasmtime maps directories into the runtime environment and how it sets up the current working directory. The test passes if I replace '.' with an empty string '' or remove the cached FileFinder instance for '.' with sys.path_importer_cache.pop('.').
./test-wasi.sh test_support -m test_forget 0:00:00 Run tests sequentially 0:00:00 [1/1] test_support test test_support failed -- Traceback (most recent call last): File "/Lib/test/test_support.py", line 116, in test_forget mod = __import__(TESTFN) ^^^^^^^^^^^^^^^^^^ ModuleNotFoundError: No module named '@test_66600_tmpæ' test_support failed (1 error) == Tests result: FAILURE == The culprit seems to be an outdated FileFinder instance: {'.': FileFinder('/.')}. The CWD is '/python-wasm/cpython/builddir/wasi/build/test_python_66600æ' when the test case is executed.
0:00:00 [1/1] test_support > /Lib/test/test_support.py(114)test_forget() -> sys.path.insert(0, os.curdir) (Pdb) p sys.path ['.', '/usr/local/lib/python312.zip', '/Lib', '/build/lib.wasi-wasm32-3.12'] (Pdb) pp sys.path_importer_cache{'.': FileFinder('/.'), '/Lib': FileFinder('/Lib'), '/Lib/collections': FileFinder('/Lib/collections'), '/Lib/encodings': FileFinder('/Lib/encodings'), '/Lib/importlib': FileFinder('/Lib/importlib'), '/Lib/re': FileFinder('/Lib/re'), '/Lib/test': FileFinder('/Lib/test'), '/Lib/test/libregrtest': FileFinder('/Lib/test/libregrtest'), '/Lib/test/support': FileFinder('/Lib/test/support'), '/Lib/unittest': FileFinder('/Lib/unittest'), '/Lib/urllib': FileFinder('/Lib/urllib'), '/build/lib.wasi-wasm32-3.12': FileFinder('/build/lib.wasi-wasm32-3.12'), '/usr/local/lib/python312.zip': None} (Pdb) p os.getcwd() '/python-wasm/cpython/builddir/wasi/build/test_python_66600æ' (Pdb) n > /Lib/test/test_support.py(115)test_forget() -> importlib.invalidate_caches() (Pdb) n > /Lib/test/test_support.py(116)test_forget() -> try: (Pdb) p sys.path ['.', '.', '/usr/local/lib/python312.zip', '/Lib', '/build/lib.wasi-wasm32-3.12'] (Pdb) pp sys.path_importer_cache{'.': FileFinder('/.'), '/Lib': FileFinder('/Lib'), '/Lib/collections': FileFinder('/Lib/collections'), '/Lib/encodings': FileFinder('/Lib/encodings'), '/Lib/importlib': FileFinder('/Lib/importlib'), '/Lib/re': FileFinder('/Lib/re'), '/Lib/test': FileFinder('/Lib/test'), '/Lib/test/libregrtest': FileFinder('/Lib/test/libregrtest'), '/Lib/test/support': FileFinder('/Lib/test/support'), '/Lib/unittest': FileFinder('/Lib/unittest'), '/Lib/urllib': FileFinder('/Lib/urllib'), '/build/lib.wasi-wasm32-3.12': FileFinder('/build/lib.wasi-wasm32-3.12'), '/usr/local/lib/python312.zip': None} A build on Linux has an absolute path to build directory as first sys.path entry.
reproducer
$ podman run --rm -ti -v $(pwd):/python-wasm/cpython:Z quay.io/tiran/cpythonbuild:emsdk3 # ./build-python-build.sh # ./build-python-wasi.sh # ./test-wasi.sh test_support -m test_forget