New submission from Jack O'Connor:
The following little script prints (but ignores) a FileNotFoundError.
import tempfile
def generator():
with tempfile.TemporaryDirectory():
yield
g = generator()
next(g)
Exception ignored in: <generator object generator at 0x7fb319fe2c60>
Traceback (most recent call last):
File "gen.py", line 6, in generator
File "/usr/lib/python3.4/tempfile.py", line 691, in __exit__
File "/usr/lib/python3.4/tempfile.py", line 697, in cleanup
File "/usr/lib/python3.4/shutil.py", line 454, in rmtree
File "/usr/lib/python3.4/shutil.py", line 452, in rmtree
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/tmp7wek4xhy'
Putting print statements in the TemporaryDirectory class shows what's happening
(confirming Guido's theory from
https://groups.google.com/forum/#!topic/python-tulip/QXgWH32P2uM): As the
program exits, the TemporaryDirectory object is finalized. This actually
rmtree's the directory. After that, the generator is finalized, which raises a
GeneratorExit inside of it. That exception causes the with statement to call
__exit__ on the already-finalized TemporaryDirectory, which tries to rmtree
again and throws the FileNotFoundError.
The main downside of this bug is just garbage on stderr. I suppose in
exceptionally unlikely circumstances, a new temp dir by the same name could be
created between the two calls, and we might actually delete something we
shouldn't. The simple fix would be to store a _was_cleaned flag or something on
the object. Is there any black magic in finalizers or multithreading that
demands something more complicated?
----------
components: Library (Lib)
messages: 226979
nosy: oconnor663
priority: normal
severity: normal
status: open
title: TemporaryDirectory attempts to clean up twice
type: behavior
versions: Python 3.4
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue22427>
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