dirs: fix out-of-bounds access in Py3
The hack for mutating Python's variable-length integers that was
ported to py3 in
cb3048746dae (dirs: port PyInt code to work on Python
3, 2016-10-08) was reading from ob_digit[1] instead of ob_digit[0] for
some reason. Space for ob_digit[1] would only be allocated for
integers larger than 30 bits, so we ended up writing to unallocated
memory. Also, we would write an integer that's 2^30 times too large,
so we would never free these integers.
Found by AddressSanitizer.
Differential Revision: https://phab.mercurial-scm.org/D7597
$ cat >> $HGRCPATH << EOF
> [extensions]
> absorb=
> EOF
Abort absorb if there is an unfinished operation.
$ hg init abortunresolved
$ cd abortunresolved
$ echo "foo1" > foo.whole
$ hg commit -Aqm "foo 1"
$ hg update null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo "foo2" > foo.whole
$ hg commit -Aqm "foo 2"
$ hg --config extensions.rebase= rebase -r 1 -d 0
rebasing 1:c3b6dc0e177a "foo 2" (tip)
merging foo.whole
warning: conflicts while merging foo.whole! (edit, then use 'hg resolve --mark')
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
$ hg --config extensions.rebase= absorb
abort: rebase in progress
(use 'hg rebase --continue' or 'hg rebase --abort')
[255]