rebase: fix bug that caused transitive copy records to disappear (
issue4192)
The defect was that copies were always duplicated against the target
revision, rather than the first parent of the revision being
rebased. This produced nominally correct results if changes were
rebased one at a time (or with --collapse), but was wrong if we
rebased a sequence of changesets which contained a sequence of copies.
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown