context: introduce merge.preferancestor for controlling which ancestor to pick
Multiple revisions can be specified in merge.preferancestor, separated by
whitespace. First match wins.
This makes it possible to overrule the default of picking the common ancestor
with the lowest hash value among the "best" (introduced in 3605d4e7e618).
This can for instance help with some merges where the 'wrong' ancestor is used.
There will thus be some overlap between this and the problems that can be
solved with a future 'consensus merge'.
Mercurial will show a note like
note: using 40663881a6dd as ancestor of 3b08d01b0ab5 and adfe50279922
alternatively, use --config merge.preferancestor=0f6b37dbe527
when the option is available, listing all the alternative ancestors.
Criss cross merging
$ hg init criss-cross
$ cd criss-cross
$ echo '0 base' > f1
$ echo '0 base' > f2
$ hg ci -Aqm '0 base'
$ echo '1 first change' > f1
$ hg ci -m '1 first change f1'
$ hg up -qr0
$ echo '2 first change' > f2
$ hg ci -qm '2 first change f2'
$ hg merge -qr 1
$ hg ci -m '3 merge'
$ hg up -qr2
$ hg merge -qr1
$ hg ci -qm '4 merge'
$ echo '5 second change' > f1
$ hg ci -m '5 second change f1'
$ hg up -r3
note: using 0f6b37dbe527 as ancestor of adfe50279922 and cf89f02107e5
alternatively, use --config merge.preferancestor=40663881a6dd
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo '6 second change' > f2
$ hg ci -m '6 second change f2'
$ hg log -G
@ changeset: 6:3b08d01b0ab5
| tag: tip
| parent: 3:cf89f02107e5
| user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: 6 second change f2
|
| o changeset: 5:adfe50279922
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: 5 second change f1
| |
| o changeset: 4:7d3e55501ae6
| |\ parent: 2:40663881a6dd
| | | parent: 1:0f6b37dbe527
| | | user: test
| | | date: Thu Jan 01 00:00:00 1970 +0000
| | | summary: 4 merge
| | |
o---+ changeset: 3:cf89f02107e5
| | | parent: 2:40663881a6dd
|/ / parent: 1:0f6b37dbe527
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: 3 merge
| |
| o changeset: 2:40663881a6dd
| | parent: 0:40494bf2444c
| | user: test
| | date: Thu Jan 01 00:00:00 1970 +0000
| | summary: 2 first change f2
| |
o | changeset: 1:0f6b37dbe527
|/ user: test
| date: Thu Jan 01 00:00:00 1970 +0000
| summary: 1 first change f1
|
o changeset: 0:40494bf2444c
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 0 base
$ hg merge -v --debug --tool internal:dump 5
note: using 0f6b37dbe527 as ancestor of 3b08d01b0ab5 and adfe50279922
alternatively, use --config merge.preferancestor=40663881a6dd
searching for copies back to rev 3
resolving manifests
branchmerge: True, force: False, partial: False
ancestor: 0f6b37dbe527, local: 3b08d01b0ab5+, remote: adfe50279922
f1: remote is newer -> g
f2: versions differ -> m
preserving f2 for resolve of f2
getting f1
updating: f1 1/2 files (50.00%)
updating: f2 2/2 files (100.00%)
picked tool 'internal:dump' for f2 (binary False symlink False)
merging f2
my f2@3b08d01b0ab5+ other f2@adfe50279922 ancestor f2@40494bf2444c
1 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
$ head *
==> f1 <==
5 second change
==> f2 <==
6 second change
==> f2.base <==
0 base
==> f2.local <==
6 second change
==> f2.orig <==
6 second change
==> f2.other <==
2 first change
$ hg up -qC .
$ hg merge -v --tool internal:dump 5 --config merge.preferancestor="null 40663881 3b08d"
note: using 40663881a6dd as ancestor of 3b08d01b0ab5 and adfe50279922
alternatively, use --config merge.preferancestor=0f6b37dbe527
resolving manifests
merging f1
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
[1]
$ cd ..