arve.knud...@gmail.com wrote:
On Oct 19, 3:48 pm, Ethan Furman <et...@stoneleaf.us> wrote:
arve.knud...@gmail.com wrote:
Hi
I thought that file objects were supposed to be garbage-collected and
automatically closed once they go out of scope, at least that's what
I've been told by more merited Python programmers. I'm also quite sure
that this is quite a common assumption in various programs, at least
given what opensource code I've seen in my time. However, the
following script doesn't work on Windows, since the file is still open
when I try to remove it:
import os.path
def create():
f = file("tmp", "w")
raise Exception
try: create()
finally:
os.remove("tmp")
So, what's the deal exactly, is the file supposed to be garbage-
collected (and closed) at the end of create?
Thanks!
Arve
When an exception is raised, the entire stack frame at that location
(which includes local vars) is saved in the exception traceback. Since
the objects are still alive, they are not GC'ed. That is why this is
better:
def create():
f = file("tmp", "w")
try:
do_stuff_that_raises_exception
finally:
os.remove("tmp")
~Ethan~
Why should this work? If I replace "do_stuff_that_raises_exception"
with "raise Exception", it fails in the same way, since the file is
open. Maybe you forgot "f.close()"? In any case, thanks for explaining
that the traceback keeps the object alive, that explains the issue.
Arve
Indeed. That should have been f.close() in the finally block. My
apologies.
~Ethan~
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