[ python-Bugs-1521491 ] file.seek() influelce write() when opened with a+ mode
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Mon Jul 24 15:53:32 CEST 2006
Bugs item #1521491, was opened at 2006-07-12 22:04
Message generated for change (Settings changed) made by gbrandl
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Category: Python Interpreter Core
Group: Python 2.5
>Status: Pending
Resolution: None
Priority: 5
Submitted By: Lior (rudnik_lior)
Assigned to: Nobody/Anonymous (nobody)
Summary: file.seek() influelce write() when opened with a+ mode
Initial Comment:
Python 2.5b1 (r25b1:47027, Jun 20 2006, 09:31:33)
Assuming documentation is correct: (from seek() help
"Note that if the file is opened for appending (mode
'a' or 'a+'), any seek() operations will be undone at
the next write"
Doing the following is __not__ undoing the seek
operation after calling this a few times (Simplified
code snippet):
from __future__ import with_statement
with open(path,'a+') as f:
f.seek(0,2) # go to end
pos = f.tell()
f.seek(0,0)
line = f.readline().strip()
f.seek(0,2) # go to end, not effective if opened
with mode a/a+ (currently bug?)
f.write("something")
Calling the above code repeatedly didnt increase the
file size beyond 166 bytes (in my code)
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Comment By: Georg Brandl (gbrandl)
Date: 2006-07-13 07:43
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I also cannot see any problem with the above code and can
append to a file indefinitely. What exactly are you
expecting the code to do, and what do you get? Which OS is this?
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Comment By: Neal Norwitz (nnorwitz)
Date: 2006-07-13 06:29
Message:
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This seems to work for me on Linux. Maybe we are testing
differently. What o/s and version are you using? Does this
work with Python 2.4? Can you attach a complete test case
that demonstrates this problem?
Thanks.
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Comment By: Lior (rudnik_lior)
Date: 2006-07-12 22:09
Message:
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Re-tried the code with empty file - it doesnt grow beyond
creating and writting at position 0 so it seems the seek
does influence the write position.
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