New submission from Evan Jones <ev...@mit.edu>:
tarfile.open() with an empty tar archive fails with a ReadError
exception. GNU tar refuses to create empty archives, but tarfile allows
it. See the following code which reproduces the error. I used the
version of tarfile.py from subversion (revision 72458) with Python 2.5
on Linux.
Exception:
Traceback (most recent call last):
File "test.py", line 15, in <module>
tar = tarfile.open(fileobj=data)
File "/home/evanj/taskmgr/tarfile.py", line 1649, in open
raise ReadError("file could not be opened successfully")
tarfile.ReadError: file could not be opened successfully
The problem seems to be that when TarFile.next() is called, it raises
the following exception for the empty tar file:
File "/home/evanj/taskmgr/tarfile.py", line 2310, in next
tarinfo = self.tarinfo.fromtarfile(self)
File "/home/evanj/taskmgr/tarfile.py", line 1235, in fromtarfile
obj = cls.frombuf(buf)
File "/home/evanj/taskmgr/tarfile.py", line 1190, in frombuf
raise HeaderError("empty header")
The attached patch works for me, but no guarantees that it doesn't cause
other problems!
Sample code:
import cStringIO
import tarfile
# Create an empty tar file
data = cStringIO.StringIO()
tar = tarfile.open(mode="w", fileobj=data)
tar.close()
print "empty tar file; length:", len(data.getvalue())
# Open the tar file
data.seek(0)
tar = tarfile.open(fileobj=data)
print tar
----------
components: Extension Modules
files: tarfile-empty.diff
keywords: patch
messages: 88416
nosy: ev...@mit.edu
severity: normal
status: open
title: tarfile:
type: behavior
Added file: http://bugs.python.org/file14093/tarfile-empty.diff
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue6123>
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