commit: remove reverse search for copy source when not in parent (issue4476)
Previously, we had weird, nonsensical behavior when committing a file move
with a missing source. This removes that weird logic and tests that the bug
this strange behavior caused is fixed. Also adds a longish comment to prevent
some poor soul from accidentally re-implementing the bug in the future.
#require execbit
$ hg init repo
$ cd repo
$ echo foo > foo
$ chmod 644 foo
$ hg ci -qAm '644'
$ chmod 755 foo
$ hg ci -qAm '755'
reverting to rev 0
$ hg revert -a -r 0
reverting foo
$ hg st
M foo
$ hg diff --git
diff --git a/foo b/foo
old mode 100755
new mode 100644
$ cd ..