git: add debug logging when there's a mismatch in the cached heads list
The dag rebuild can be expensive, so let's try and avoid bugs where it
transparently rebuilds all the time for no reason. This would have
prevented the issue fixed in D8622.
Differential Revision: https://phab.mercurial-scm.org/D8625
#require symlink
https://bz.mercurial-scm.org/1438
$ hg init
$ ln -s foo link
$ hg add link
$ hg ci -mbad link
$ hg rm link
$ hg ci -mok
$ hg diff -g -r 0:1 > bad.patch
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg import --no-commit bad.patch
applying bad.patch
$ hg status
R link
? bad.patch