backout: deprecate/hide support for backing out merges
This has never worked usefully:
- it can't undo a completely unwanted merge, as it leaves the merge in the DAG
- it can't undo a faulty merge as that means doing a merge correctly,
not simply reverting to one or the other parent
Both of these kinds of merge also require coordinated action among
developers to avoid the bad merge continuing to affect future merges,
so we should stop pretending that backout is of any help here.
As backing out a merge now requires a hidden option, it can't be done
by accident, but will continue to 'work' for anyone who's already
dependent on --parent for some unknown reason.
http://mercurial.selenic.com/bts/issue672
# 0-2-4
# \ \ \
# 1-3-5
#
# rename in #1, content change in #4.
$ hg init
$ touch 1
$ touch 2
$ hg commit -Am init # 0
adding 1
adding 2
$ hg rename 1 1a
$ hg commit -m rename # 1
$ hg co -C 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo unrelated >> 2
$ hg ci -m unrelated1 # 2
created new head
$ hg merge --debug 1
searching for copies back to rev 1
unmatched files in other:
1a
all copies found (* = to merge, ! = divergent):
1a -> 1
checking for directory renames
resolving manifests
overwrite None partial False
ancestor 81f4b099af3d local c64f439569a9+ remote c12dcd37c90a
1: other deleted -> r
1a: remote created -> g
updating: 1 1/2 files (50.00%)
removing 1
updating: 1a 2/2 files (100.00%)
getting 1a
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m merge1 # 3
$ hg co -C 2
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo hello >> 1
$ hg ci -m unrelated2 # 4
created new head
$ hg co -C 3
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg merge -y --debug 4
searching for copies back to rev 1
unmatched files in local:
1a
all copies found (* = to merge, ! = divergent):
1a -> 1 *
checking for directory renames
resolving manifests
overwrite None partial False
ancestor c64f439569a9 local e327dca35ac8+ remote 746e9549ea96
1a: local copied/moved to 1 -> m
preserving 1a for resolve of 1a
updating: 1a 1/1 files (100.00%)
picked tool 'internal:merge' for 1a (binary False symlink False)
merging 1a and 1 to 1a
my 1a@e327dca35ac8+ other 1@746e9549ea96 ancestor 1@81f4b099af3d
premerge successful
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg co -C 4
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg merge -y --debug 3
searching for copies back to rev 1
unmatched files in other:
1a
all copies found (* = to merge, ! = divergent):
1a -> 1 *
checking for directory renames
resolving manifests
overwrite None partial False
ancestor c64f439569a9 local 746e9549ea96+ remote e327dca35ac8
1: remote moved to 1a -> m
preserving 1 for resolve of 1a
removing 1
updating: 1 1/1 files (100.00%)
picked tool 'internal:merge' for 1a (binary False symlink False)
merging 1 and 1a to 1a
my 1a@746e9549ea96+ other 1a@e327dca35ac8 ancestor 1@81f4b099af3d
premerge successful
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)