[Python-apps-team] Bug#636396: mercurial: Cloning fails with: mpatch.mpatchError: patch cannot be decoded

[Arno Huggenfeld]

Ok,

third try.

----------------------------------------
As it seems that my first two mails vanished in the spam filter, next try with different settings.
----------------------------------------
I discovered by chance that mercurial is working after

# echo 2 > /proc/cpu/alignment
(meaning fix problem, default 0 means do nothing)

which strongly suggests that there is an alignment problem in mpatch.c . Most of the times it is code which implicitly relies on a specific alignment of structure members or array elements, which is not standardized and cpu, os and compiler specific. http://netwinder.osuosl.org/users/b/brianbr/public_html/alignment.html and http://lecs.cs.ucla.edu/wiki/index.php have good explanations.

Cheers
Arno
----------------------------------------
I did some experiments with various versions:

1.8.3-1 (wheezy): only working with echo 2 > /proc/cpu/alignment
1.8.4+174-6ab8b17adc03 (upstream hg-stable): only working with echo 2 > /proc/cpu/alignment
1.9.1 (upstream previous release): only working with echo 2 > /proc/cpu/alignment
1.9.1-2 (sid): only working with echo 2 > /proc/cpu/alignment
1.9.2 (upstream latest release): working
1.9.2+17-d23dfcbb8840+20110912 (upstream main): working

All tests were limited to hg verify on a small repository. It is not mentioned in the release notes but something was fixed between 1.9.1 and 1.9.2. Therefore I suggest Debian upgrading to 1.9.2.

Cheers
Arno