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gh-133982: Run unclosed file test on all io implementations #134165

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Merged
merged 2 commits into from
May 21, 2025
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gh-133982: Run unclosed file test on all io implementations #134165

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cd3b196
gh-133982: Run unclosed file test on all io implementations
cmaloney May 13, 2025
704bf46
Rely on IOBase __del__ implementation in FileIO
cmaloney May 18, 2025
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18 changes: 14 additions & 4 deletions Lib/_pyio.py
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Original file line number Diff line number Diff line change
Expand Up @@ -407,6 +407,9 @@ def __del__(self):
if closed:
return

if dealloc_warn := getattr(self, "_dealloc_warn", None):
dealloc_warn(self)

# If close() fails, the caller logs the exception with
# sys.unraisablehook. close() must be called at the end at __del__().
self.close()
Expand Down Expand Up @@ -853,6 +856,10 @@ def __repr__(self):
else:
return "<{}.{} name={!r}>".format(modname, clsname, name)

def _dealloc_warn(self, source):
if dealloc_warn := getattr(self.raw, "_dealloc_warn", None):
dealloc_warn(source)

### Lower-level APIs ###

def fileno(self):
Expand Down Expand Up @@ -1600,12 +1607,11 @@ def __init__(self, file, mode='r', closefd=True, opener=None):
raise
self._fd = fd

def __del__(self):
def _dealloc_warn(self, source):
if self._fd >= 0 and self._closefd and not self.closed:
import warnings
warnings.warn('unclosed file %r' % (self,), ResourceWarning,
warnings.warn(f'unclosed file {source!r}', ResourceWarning,
stacklevel=2, source=self)
self.close()

def __getstate__(self):
raise TypeError(f"cannot pickle {self.__class__.__name__!r} object")
Expand Down Expand Up @@ -1780,7 +1786,7 @@ def close(self):
if not self.closed:
self._stat_atopen = None
try:
if self._closefd:
if self._closefd and self._fd >= 0:
os.close(self._fd)
finally:
super().close()
Expand Down Expand Up @@ -2689,6 +2695,10 @@ def readline(self, size=None):
def newlines(self):
return self._decoder.newlines if self._decoder else None

def _dealloc_warn(self, source):
if dealloc_warn := getattr(self.buffer, "_dealloc_warn", None):
dealloc_warn(source)


class StringIO(TextIOWrapper):
"""Text I/O implementation using an in-memory buffer.
Expand Down
4 changes: 2 additions & 2 deletions Lib/test/test_io.py
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Original file line number Diff line number Diff line change
Expand Up @@ -4417,7 +4417,7 @@ def test_abc_inheritance_official(self):
self._check_abc_inheritance(io)

def _check_warn_on_dealloc(self, *args, **kwargs):
f = open(*args, **kwargs)
f = self.open(*args, **kwargs)
r = repr(f)
with self.assertWarns(ResourceWarning) as cm:
f = None
Expand Down Expand Up @@ -4446,7 +4446,7 @@ def cleanup_fds():
r, w = os.pipe()
fds += r, w
with warnings_helper.check_no_resource_warning(self):
open(r, *args, closefd=False, **kwargs)
self.open(r, *args, closefd=False, **kwargs)

@unittest.skipUnless(hasattr(os, "pipe"), "requires os.pipe()")
def test_warn_on_dealloc_fd(self):
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2025-05-17-20-23-57.gh-issue-133982.smS7au.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Emit :exc:`RuntimeWarning` in the Python implementation of :mod:`io` when
the :term:`file-like object <file object>` is not closed explicitly in the
presence of multiple I/O layers.
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