py2exe and library.zip

[Peter Hansen]

David Bolen wrote:
> Peter Hansen <peter at engcorp.com> writes:
>>Do you know that Subversion has (as I understand it) a fairly
>>intelligent binary file comparison routine, and it will (again, as I
>>understand it) not transmit the entire contents of the zip file but
>>would actually send only the portions that have changed?  At least,
>>that's if the file isn't compressed in some way that prevents this
>>algorithm from working well.  (Note to self: check if zip files that
>>can be in sys.path can be compressed, and if py2exe compresses them.)
> 
> Even if the files were compressed, which has a net result similar to
> randomizing the contents and will certainly extend the portion that
> appears "changed", the worst that would happen is that subversion
> (which does use a binary delta algorithm) would end up downloading the
> single file portion of the zip file rather than the smaller change
> within the file.  It should still be efficient.

Good point.  When I wrote that I was picturing the form of compression 
that a .tar.gz file would have, not what is actually used inside a .zip 
file which is -- quite logically now that you point it out -- done on a 
file-by-file basis.  (Clearly to do otherwise would risk your data and 
make changing compressed zips highly inefficient.)

-Peter