Closed as not planned
Closed as not planned
Description
Bug report
Bug description:
redirect_stdout/stderr does not work if freethreading is enabled.
The following example shows the problem:
# /// script
# dependencies = [
# "pytest",
# "pytest-run-parallel"
# ]
# ///
from contextlib import redirect_stdout
from io import StringIO
import time
def test_redirect():
text=StringIO()
with redirect_stdout(text):
print("hello")
time.sleep(1)
print("hello")
assert text.getvalue()=="hello\nhello\n"
if __name__ == "__main__":
import pytest
pytest.main(["--parallel-threads=5",__file__])output:
❯ uv run -p 3.13t bug.py
================================== test session starts ==================================
platform linux -- Python 3.13.1, pytest-8.3.4, pluggy-1.5.0
rootdir: /home/frank/projects/bugs/pytest_redirect
plugins: run-parallel-0.3.1
collected 1 item
bug.py F [100%]
======================================= FAILURES ========================================
_____________________________________ test_redirect _____________________________________
def test_redirect():
text=StringIO()
with redirect_stdout(text):
print("hello")
time.sleep(1)
print("hello")
> assert text.getvalue()=="hello\nhello\n"
E AssertionError: assert 'hello\n' == 'hello\nhello\n'
E
E hello
E - hello
bug.py:22: AssertionError
================================ short test summary info ================================
FAILED bug.py::test_redirect - AssertionError: assert 'hello\n' == 'hello\nhello\n'
=================================== 1 failed in 1.04s ===================================
The underlying problem is probably the global sys.stdout/stderr state which is shared between threads.
Is it possible to make these thread local?
CPython versions tested on:
3.13
Operating systems tested on:
No response