Nicolas Pitre <nico@xxxxxxx> writes:
> On a 32-bit system, the maximum possible size for an object is less than
> 4GB, while 64-bit systems may cope with larger objects. Due to this
> limitation, variables holding object sizes are using an unsigned long
> type (32 bits on 32-bit systems, or 64 bits on 64-bit systems).
>
> When large objects are encountered, and/or people play with large delta
> depth values, it is possible for the maximum allowed delta size
> computation to overflow, especially on a 32-bit system. When this
> occurs, surviving result bits may represent a value much smaller than
> what it is supposed to be, or even zero. This prevents some objects
> from being deltified although they do get deltified when a smaller depth
> limit is used. Fix this by always performing a 64-bit multiplication.
>
> Signed-off-by: Nicolas Pitre <nico@xxxxxxx>
I added this patch and rerun the 2 test cases form the table where
--depth is 20000 and 95000, and got the following result:
--depth=20000 => file size: 19126077 delta: 73814
--depth=95000 => file size: 19126087 delta: 73814
So, it seems that this patch almost fixed the issue. But notice that
the pack file was 10 bytes larger for the --depth=95000 case.
I made a small perl script to compare the output from 'git verify-pack
-v' of the 2 idx/pack files, and found the following difference(1)
(first line from --depth=20000 case, second from --depth=95000):
fe0a6f3e971373590714dbafd087b235ea60ac00 tree 9 19 18921247 731 96a3ec5789504e6d0f90c99fb1937af1ebd58e2d
fe0a6f3e971373590714dbafd087b235ea60ac00 tree 20 29 18921247 730 12e560f7fb28558b15e3a2008fba860f9a4b2222
'git show fe0a6f3e971373590714dbafd087b235ea60ac00' =>
tree fe0a6f3e971373590714dbafd087b235ea60ac00
Makefile
t0000-basic.sh
test-lib.sh
'git show 96a3ec5789504e6d0f90c99fb1937af1ebd58e2d' =>
tree 96a3ec5789504e6d0f90c99fb1937af1ebd58e2d
Makefile
t0000-basic.sh
t0100-environment-names.sh
t0200-update-cache.sh
t0400-ls-files.sh
t0500-ls-files.sh
t1000-checkout-cache.sh
t1001-checkout-cache.sh
test-lib.sh
'git show 12e560f7fb28558b15e3a2008fba860f9a4b2222' =>
tree 12e560f7fb28558b15e3a2008fba860f9a4b2222
Makefile
t0000-basic.sh
t0100-environment-names.sh
t0200-update-cache.sh
t0400-ls-files.sh
t0500-ls-files.sh
t1000-checkout-cache.sh
t1001-checkout-cache.sh
test-lib.sh
-- kjetil
1) there was lots of lines with different offsets, all of which was 10
larger in the --depth=95000 case.
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