tempfile.NamedTemporaryFile leaks file descriptor when fdopen fails

[tholzer]

BPO	21058
Nosy	@vstinner, @vajrasky
Files	fix_typo_21058.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2014-03-25.08:22:10.393>
created_at = <Date 2014-03-25.04:47:27.720>
labels = ['library', 'performance']
title = 'tempfile.NamedTemporaryFile leaks file descriptor when fdopen fails'
updated_at = <Date 2014-03-25.17:19:59.155>
user = 'https://bugs.python.org/tholzer'

bugs.python.org fields:

activity = <Date 2014-03-25.17:19:59.155>
actor = 'python-dev'
assignee = 'none'
closed = True
closed_date = <Date 2014-03-25.08:22:10.393>
closer = 'vstinner'
components = ['Library (Lib)']
creation = <Date 2014-03-25.04:47:27.720>
creator = 'tholzer'
dependencies = []
files = ['34617']
hgrepos = []
issue_num = 21058
keywords = ['patch']
message_count = 7.0
messages = ['214778', '214779', '214780', '214783', '214786', '214830', '214841']
nosy_count = 4.0
nosy_names = ['vstinner', 'tholzer', 'python-dev', 'vajrasky']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'resource usage'
url = 'https://bugs.python.org/issue21058'
versions = ['Python 2.7']

[tholzer]

The NamedTemporaryFile inside the standard tempfile library leaks an open file descriptor when fdopen fails.

Test case:

# ulimit -SHn 50
# python test1.py

from tempfile import NamedTemporaryFile

while 1:
    try:
        NamedTemporaryFile(mode='x')
    except ValueError as ex:
        pass

Output:

Traceback (most recent call last):
  File "./a2.py", line 7, in <module>
  File "/usr/lib/python2.7/tempfile.py", line 454, in NamedTemporaryFile
  File "/usr/lib/python2.7/tempfile.py", line 235, in _mkstemp_inner
OSError: [Errno 24] Too many open files: '/tmp/tmpI0MIEW'
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 66, in apport_excepthook
ImportError: No module named fileutils

Original exception was:
Traceback (most recent call last):
  File "./a2.py", line 7, in <module>
  File "/usr/lib/python2.7/tempfile.py", line 454, in NamedTemporaryFile
  File "/usr/lib/python2.7/tempfile.py", line 235, in _mkstemp_inner
OSError: [Errno 24] Too many open files: '/tmp/tmpI0MIEW'

Patch:

@@ -452,7 +452,11 @@
         flags |= _os.O_TEMPORARY
 
     (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
-    file = _os.fdopen(fd, mode, bufsize)
+    try:
+        file = _os.fdopen(fd, mode, bufsize)
+    except Exception as ex:
+        _os.close(fd)
+        raise
     return _TemporaryFileWrapper(file, name, delete)
 
 if _os.name != 'posix' or _os.sys.platform == 'cygwin':

[python-dev]

New changeset f2f0eec4a556 by Victor Stinner in branch '2.7':
Issue bpo-21058: Fix a leak of file descriptor in tempfile.NamedTemporaryFile(),
http://hg.python.org/cpython/rev/f2f0eec4a556

[python-dev]

New changeset 182f08c0dd45 by Victor Stinner in branch '2.7':
Issue bpo-21058: NamedTemporaryFile() closes the FD on any error, not only Exception
http://hg.python.org/cpython/rev/182f08c0dd45

[python-dev]

New changeset 7f87c26f59ab by Victor Stinner in branch '3.4':
Issue bpo-21058: Fix a leak of file descriptor in tempfile.NamedTemporaryFile(),
http://hg.python.org/cpython/rev/7f87c26f59ab

New changeset b1e3035216f8 by Victor Stinner in branch 'default':
(Merge 3.4) Issue bpo-21058: Fix a leak of file descriptor in
http://hg.python.org/cpython/rev/b1e3035216f8

[vstinner]

Thanks for the report, the issue is now fixed.

[vajrasky]

There is a typo.

s/io.pen/io.open/

[python-dev]

New changeset aa2a05fe46ae by Victor Stinner in branch '3.4':
Issue bpo-21058: fix typo in a comment. Patch written by Vajrasky Kok.
http://hg.python.org/cpython/rev/aa2a05fe46ae

New changeset 4e3c76cb0e8a by Victor Stinner in branch 'default':
(Merge 3.4) Issue bpo-21058: fix typo in a comment. Patch written by Vajrasky Kok.
http://hg.python.org/cpython/rev/4e3c76cb0e8a