Re: [PATCH] git-p4: close temporary file before removing
31.07.2019, 17:52, "Philip McGraw" <philip.mcgraw@bentley.com>:
Show 59 quoted lines
> 2019.07.31 10:09 Andrey <ahippo@yandex.ru>
>> 31.07.2019, 09:53, "Philip McGraw" <philip.mcgraw@bentley.com>:
>>>> 30.07.2019, 13:37, "Philip McGraw" <philip.mcgraw@bentley.com>:
>>>> > python os.remove() throws exceptions on Windows platform when attempting
>>>> > to remove file while it is still open. Need to grab filename while file open,
>>>> > close file handle, then remove by name. Apparently other platforms are more
>>>> > permissive of removing files while busy.
>>>> > reference:
>>>> > ---
>>>> > git-p4.py | 4 +++-
>>>> > 1 file changed, 3 insertions(+), 1 deletion(-)
>>>> >
>>>> > diff --git a/git-p4.py b/git-p4.py
>>>> > index c71a6832e2..6b9d2a8317 100755
>>>> > --- a/git-p4.py
>>>> > +++ b/git-p4.py
>>>> > @@ -1161,12 +1161,14 @@ def exceedsLargeFileThreshold(self, relPath, contents):
>>>> > return False
>>>> > contentTempFile = self.generateTempFile(contents)
>>>> > compressedContentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=False)
>>>> > + compressedContentFileName = compressedContentFile.name
>>>> > zf = zipfile.ZipFile(compressedContentFile.name, mode='w')
>>>> > zf.write(contentTempFile, compress_type=zipfile.ZIP_DEFLATED)
>>>> > zf.close()
>>>> > compressedContentsSize = zf.infolist()[0].compress_size
>>>> > os.remove(contentTempFile)
>>>> > - os.remove(compressedContentFile.name)
>>>> > + compressedContentFile.close()
>>>> > + os.remove(compressedContentFileName)
>>>>
>>>> I'm not sure why NamedTemporaryFile() is called with delete=False above,
>>>> but it appears to me that it can have delete=True instead,
>>>> so that there is no need to call os.remove() explicitly
>>>> and thus worry about remove vs close ordering at all.
>>>>
>>>> > if compressedContentsSize > gitConfigInt('git-p4.largeFileCompressedThreshold'):
>>>> > return True
>>>> > return False
>>>> > --
>>>> > 2.21.0.windows.1
>>>>
>>>> Thank you,
>>>> Andrey.
>>>
>>> Thanks Andrey; simpler is certainly better! I will test and re-submit v2 of patch with that approach.
>>
>> Thank you, that would be great!
>>
>> --
>> Andrey.
>
> Unfortunately it wasn't as simple it seemed: upon testing with only changing delete=True,
> found that the problem was not solved. Upon further debugging, recoded/refactored slightly adding
> allocateTempFileName() locally scoped function to try to clarify how the NamedTemporaryFile()
> was actually being used.
>
> We can't depend on the delete-on-close because the NamedTemporaryFile() is merely allocating
> a temporary name for real use by the zipfile open-for-write which fails (on Windows) if file
> was not explicitly closed first.Oh, sorry for misguiding you! I didn't think of this aspect.
> Hopefully the new patch (https://github.com/gitgitgadget/git/pull/301) will make this more clear.
The new changeset looks good to me. (I'll post a reply in that thread too)
> Open to other suggestions if still not clear.
Just as a thought, ZipFile() can take a file-like object instead of a file name, so can be passed the NamedTemporaryFile() object directly instead of its file name. This should hopefully avoid double-open issue on Windows.
However, I'm good with your allocateTempFileName() changeset, so it's up to you to give it a try or not.
> Thanks again,
> Philip
Philip McGraw