[oe] [PATCH 1/3] gitkpkgv: Ensure files are closed
Richard Purdie
richard.purdie at linuxfoundation.org
Tue Jun 7 13:49:42 UTC 2016
On Tue, 2016-06-07 at 11:02 +0200, Mike Looijmans wrote:
> Looks like regression in Python itself?
>
> In both Python 2 and 3, the file is closed properly if the file
> object is not
> being stored:
>
> >>> import os
> >>> os.listdir('/proc/self/fd')
> ['0', '1', '2', '3']
> >>> l=open('/proc/self/stat').readline()
> >>> os.listdir('/proc/self/fd')
> ['0', '1', '2', '3']
> >>> f=open('/proc/self/stat')
> >>> os.listdir('/proc/self/fd')
> ['0', '1', '2', '3', '4']
> >>>
>
>
> (file descriptor "3" is the one being used to read the /proc/self/fd
> directory, "4" is the one used for reading the stat file)
>
> The "with" construction should not be needed here. Something else is
> causing
> this (e.g. nested function definition or exception handler?).
$ python2 -Wdefault -c "open('/bin/bash')"
$ python3 -Wdefault -c "open('/bin/bash')"
-c:1: ResourceWarning: unclosed file <_io.TextIOWrapper name='/bin/bash' mode='r' encoding='UTF-8'>
Admittedly its not an out the box warning but it is one that seems to
be enabled under bitbake. Details in:
https://bugs.python.org/issue10093
but the gist of the issue is that relying on the garbage collector to
close files is a cpython'ism and other implementations of python may
not do this.
So whilst "with" might not be strictly required, it is recommended.
Cheers,
Richard
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