merge: minimize conflicts when common base is not shown (
issue4447)
Previously, two changes that were nearly, but not quite, identical would result
in large merge conflict regions that looked very similar, and were thus very
confusing to users, and lead people used to other source control systems to
claim that "mercurial's merge algorithms suck". In the relatively common case
of a new file being introduced in two branches with very slight modifications,
the old behavior would show the entire file as a conflict, and it would be very
difficult for a user to determine what was going on.
In the past, mercurial attempted to solve this with a "very smart" algorithm
that would find all common lines, but this has significant problems as
described in
2ea6d906cf9b.
Instead, we use a "very dumb" algorithm introduced in the previous patch that
simply matches lines at the periphery of conflict regions. This minimizes most
conflict regions well, though there may still be some degenerate edge cases,
like small modification to the beginning and end of a large file.
$ hg init a
$ cd a
$ echo 'root' >root
$ hg add root
$ hg commit -d '0 0' -m "Adding root node"
$ echo 'a' >a
$ hg add a
$ hg branch a
marked working directory as branch a
(branches are permanent and global, did you want a bookmark?)
$ hg commit -d '1 0' -m "Adding a branch"
$ hg branch q
marked working directory as branch q
$ echo 'aa' >a
$ hg branch -C
reset working directory to branch a
$ hg commit -d '2 0' -m "Adding to a branch"
$ hg update -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'b' >b
$ hg add b
$ hg branch b
marked working directory as branch b
$ hg commit -d '2 0' -m "Adding b branch"
$ echo 'bh1' >bh1
$ hg add bh1
$ hg commit -d '3 0' -m "Adding b branch head 1"
$ hg update -C 2
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo 'bh2' >bh2
$ hg add bh2
$ hg commit -d '4 0' -m "Adding b branch head 2"
$ echo 'c' >c
$ hg add c
$ hg branch c
marked working directory as branch c
$ hg commit -d '5 0' -m "Adding c branch"
reserved names
$ hg branch tip
abort: the name 'tip' is reserved
[255]
$ hg branch null
abort: the name 'null' is reserved
[255]
$ hg branch .
abort: the name '.' is reserved
[255]
invalid characters
$ hg branch 'foo:bar'
abort: ':' cannot be used in a name
[255]
$ hg branch 'foo
> bar'
abort: '\n' cannot be used in a name
[255]
trailing or leading spaces should be stripped before testing duplicates
$ hg branch 'b '
abort: a branch of the same name already exists
(use 'hg update' to switch to it)
[255]
$ hg branch ' b'
abort: a branch of the same name already exists
(use 'hg update' to switch to it)
[255]
verify update will accept invalid legacy branch names
$ hg init test-invalid-branch-name
$ cd test-invalid-branch-name
$ hg pull -u "$TESTDIR"/bundles/test-invalid-branch-name.hg
pulling from *test-invalid-branch-name.hg (glob)
requesting all changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 2 files
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg update '"colon:test"'
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
$ echo 'd' >d
$ hg add d
$ hg branch 'a branch name much longer than the default justification used by branches'
marked working directory as branch a branch name much longer than the default justification used by branches
$ hg commit -d '6 0' -m "Adding d branch"
$ hg branches
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 4:aee39cd168d0
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
-------
$ hg branches -a
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 4:aee39cd168d0
--- Branch a
$ hg log -b a
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 2:881fe2b92ad0
branch: a
user: test
date: Thu Jan 01 00:00:02 1970 +0000
summary: Adding to a branch
changeset: 1:dd6b440dd85a
branch: a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: Adding a branch
---- Branch b
$ hg log -b b
changeset: 4:aee39cd168d0
branch: b
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: Adding b branch head 1
changeset: 3:ac22033332d1
branch: b
parent: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:02 1970 +0000
summary: Adding b branch
---- going to test branch closing
$ hg branches
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 4:aee39cd168d0
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg up -C b
2 files updated, 0 files merged, 4 files removed, 0 files unresolved
$ echo 'xxx1' >> b
$ hg commit -d '7 0' -m 'adding cset to branch b'
$ hg up -C aee39cd168d0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo 'xxx2' >> b
$ hg commit -d '8 0' -m 'adding head to branch b'
created new head
$ echo 'xxx3' >> b
$ hg commit -d '9 0' -m 'adding another cset to branch b'
$ hg branches
b 10:bfbe841b666e
a branch name much longer than the default justification used by branches 7:10ff5895aa57
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg heads --closed
changeset: 10:bfbe841b666e
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: adding another cset to branch b
changeset: 8:eebb944467c9
branch: b
parent: 4:aee39cd168d0
user: test
date: Thu Jan 01 00:00:07 1970 +0000
summary: adding cset to branch b
changeset: 7:10ff5895aa57
branch: a branch name much longer than the default justification used by branches
user: test
date: Thu Jan 01 00:00:06 1970 +0000
summary: Adding d branch
changeset: 6:589736a22561
branch: c
user: test
date: Thu Jan 01 00:00:05 1970 +0000
summary: Adding c branch
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
$ hg heads
changeset: 10:bfbe841b666e
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: adding another cset to branch b
changeset: 8:eebb944467c9
branch: b
parent: 4:aee39cd168d0
user: test
date: Thu Jan 01 00:00:07 1970 +0000
summary: adding cset to branch b
changeset: 7:10ff5895aa57
branch: a branch name much longer than the default justification used by branches
user: test
date: Thu Jan 01 00:00:06 1970 +0000
summary: Adding d branch
changeset: 6:589736a22561
branch: c
user: test
date: Thu Jan 01 00:00:05 1970 +0000
summary: Adding c branch
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
$ hg commit -d '9 0' --close-branch -m 'prune bad branch'
$ hg branches -a
b 8:eebb944467c9
a branch name much longer than the default justification used by branches 7:10ff5895aa57
$ hg up -C b
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg commit -d '9 0' --close-branch -m 'close this part branch too'
$ hg commit -d '9 0' --close-branch -m 're-closing this branch'
abort: can only close branch heads
[255]
$ hg log -r tip --debug
changeset: 12:e3d49c0575d8fc2cb1cd6859c747c14f5f6d499f
branch: b
tag: tip
phase: draft
parent: 8:eebb944467c9fb9651ed232aeaf31b3c0a7fc6c1
parent: -1:0000000000000000000000000000000000000000
manifest: 8:6f9ed32d2b310e391a4f107d5f0f071df785bfee
user: test
date: Thu Jan 01 00:00:09 1970 +0000
extra: branch=b
extra: close=1
description:
close this part branch too
--- b branch should be inactive
$ hg branches
a branch name much longer than the default justification used by branches 7:10ff5895aa57
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg branches -c
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 12:e3d49c0575d8 (closed)
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg branches -a
a branch name much longer than the default justification used by branches 7:10ff5895aa57
$ hg branches -q
a branch name much longer than the default justification used by branches
c
a
default
$ hg heads b
no open branch heads found on branches b
[1]
$ hg heads --closed b
changeset: 12:e3d49c0575d8
branch: b
tag: tip
parent: 8:eebb944467c9
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: close this part branch too
changeset: 11:d3f163457ebf
branch: b
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: prune bad branch
$ echo 'xxx4' >> b
$ hg commit -d '9 0' -m 'reopen branch with a change'
reopening closed branch head 12
--- branch b is back in action
$ hg branches -a
b 13:e23b5505d1ad
a branch name much longer than the default justification used by branches 7:10ff5895aa57
---- test heads listings
$ hg heads
changeset: 13:e23b5505d1ad
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: reopen branch with a change
changeset: 7:10ff5895aa57
branch: a branch name much longer than the default justification used by branches
user: test
date: Thu Jan 01 00:00:06 1970 +0000
summary: Adding d branch
changeset: 6:589736a22561
branch: c
user: test
date: Thu Jan 01 00:00:05 1970 +0000
summary: Adding c branch
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
branch default
$ hg heads default
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
branch a
$ hg heads a
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
$ hg heads --active a
no open branch heads found on branches a
[1]
branch b
$ hg heads b
changeset: 13:e23b5505d1ad
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: reopen branch with a change
$ hg heads --closed b
changeset: 13:e23b5505d1ad
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: reopen branch with a change
changeset: 11:d3f163457ebf
branch: b
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: prune bad branch
default branch colors:
$ cat <<EOF >> $HGRCPATH
> [extensions]
> color =
> [color]
> mode = ansi
> EOF
$ hg up -C c
3 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg commit -d '9 0' --close-branch -m 'reclosing this branch'
$ hg up -C b
2 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ hg branches --color=always
\x1b[0;32mb\x1b[0m\x1b[0;33m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;33m 7:10ff5895aa57\x1b[0m (esc)
\x1b[0;0ma\x1b[0m\x1b[0;33m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;0mdefault\x1b[0m\x1b[0;33m 0:19709c5a4e75\x1b[0m (inactive) (esc)
default closed branch color:
$ hg branches --color=always --closed
\x1b[0;32mb\x1b[0m\x1b[0;33m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;33m 7:10ff5895aa57\x1b[0m (esc)
\x1b[0;30;1mc\x1b[0m\x1b[0;33m 14:f894c25619d3\x1b[0m (closed) (esc)
\x1b[0;0ma\x1b[0m\x1b[0;33m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;0mdefault\x1b[0m\x1b[0;33m 0:19709c5a4e75\x1b[0m (inactive) (esc)
$ cat <<EOF >> $HGRCPATH
> [extensions]
> color =
> [color]
> branches.active = green
> branches.closed = blue
> branches.current = red
> branches.inactive = magenta
> log.changeset = cyan
> EOF
custom branch colors:
$ hg branches --color=always
\x1b[0;31mb\x1b[0m\x1b[0;36m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;36m 7:10ff5895aa57\x1b[0m (esc)
\x1b[0;35ma\x1b[0m\x1b[0;36m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;35mdefault\x1b[0m\x1b[0;36m 0:19709c5a4e75\x1b[0m (inactive) (esc)
custom closed branch color:
$ hg branches --color=always --closed
\x1b[0;31mb\x1b[0m\x1b[0;36m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m\x1b[0;36m 7:10ff5895aa57\x1b[0m (esc)
\x1b[0;34mc\x1b[0m\x1b[0;36m 14:f894c25619d3\x1b[0m (closed) (esc)
\x1b[0;35ma\x1b[0m\x1b[0;36m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;35mdefault\x1b[0m\x1b[0;36m 0:19709c5a4e75\x1b[0m (inactive) (esc)
template output:
$ hg branches -Tjson --closed
[
{
"active": true,
"branch": "b",
"closed": false,
"current": true,
"node": "e23b5505d1ad24aab6f84fd8c7cb8cd8e5e93be0",
"rev": 13
},
{
"active": true,
"branch": "a branch name much longer than the default justification used by branches",
"closed": false,
"current": false,
"node": "10ff5895aa5793bd378da574af8cec8ea408d831",
"rev": 7
},
{
"active": false,
"branch": "c",
"closed": true,
"current": false,
"node": "f894c25619d3f1484639d81be950e0a07bc6f1f6",
"rev": 14
},
{
"active": false,
"branch": "a",
"closed": false,
"current": false,
"node": "d8cbc61dbaa6dc817175d1e301eecb863f280832",
"rev": 5
},
{
"active": false,
"branch": "default",
"closed": false,
"current": false,
"node": "19709c5a4e75bf938f8e349aff97438539bb729e",
"rev": 0
}
]
Tests of revision branch name caching
We rev branch cache is updated automatically. In these tests we use a trick to
trigger rebuilds. We remove the branch head cache and run 'hg head' to cause a
rebuild that also will populate the rev branch cache.
revision branch cache is created when building the branch head cache
$ rm -rf .hg/cache; hg head a -T '{rev}\n'
5
$ f --hexdump --size .hg/cache/rbc-*
.hg/cache/rbc-names-v1: size=87
0000: 64 65 66 61 75 6c 74 00 61 00 62 00 63 00 61 20 |default.a.b.c.a |
0010: 62 72 61 6e 63 68 20 6e 61 6d 65 20 6d 75 63 68 |branch name much|
0020: 20 6c 6f 6e 67 65 72 20 74 68 61 6e 20 74 68 65 | longer than the|
0030: 20 64 65 66 61 75 6c 74 20 6a 75 73 74 69 66 69 | default justifi|
0040: 63 61 74 69 6f 6e 20 75 73 65 64 20 62 79 20 62 |cation used by b|
0050: 72 61 6e 63 68 65 73 |ranches|
.hg/cache/rbc-revs-v1: size=120
0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
0010: 88 1f e2 b9 00 00 00 01 ac 22 03 33 00 00 00 02 |.........".3....|
0020: ae e3 9c d1 00 00 00 02 d8 cb c6 1d 00 00 00 01 |................|
0030: 58 97 36 a2 00 00 00 03 10 ff 58 95 00 00 00 04 |X.6.......X.....|
0040: ee bb 94 44 00 00 00 02 5f 40 61 bb 00 00 00 02 |...D...._@a.....|
0050: bf be 84 1b 00 00 00 02 d3 f1 63 45 80 00 00 02 |..........cE....|
0060: e3 d4 9c 05 80 00 00 02 e2 3b 55 05 00 00 00 02 |.........;U.....|
0070: f8 94 c2 56 80 00 00 03 |...V....|
#if unix-permissions no-root
no errors when revbranchcache is not writable
$ echo >> .hg/cache/rbc-revs-v1
$ chmod a-w .hg/cache/rbc-revs-v1
$ rm -f .hg/cache/branch* && hg head a -T '{rev}\n'
5
$ chmod a+w .hg/cache/rbc-revs-v1
#endif
recovery from invalid cache revs file with trailing data
$ echo >> .hg/cache/rbc-revs-v1
$ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
5
truncating cache/rbc-revs-v1 to 120
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=120
recovery from invalid cache file with partial last record
$ mv .hg/cache/rbc-revs-v1 .
$ f -qDB 119 rbc-revs-v1 > .hg/cache/rbc-revs-v1
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=119
$ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
5
truncating cache/rbc-revs-v1 to 112
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=120
recovery from invalid cache file with missing record - no truncation
$ mv .hg/cache/rbc-revs-v1 .
$ f -qDB 112 rbc-revs-v1 > .hg/cache/rbc-revs-v1
$ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
5
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=120
recovery from invalid cache file with some bad records
$ mv .hg/cache/rbc-revs-v1 .
$ f -qDB 8 rbc-revs-v1 > .hg/cache/rbc-revs-v1
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=8
$ f -qDB 112 rbc-revs-v1 >> .hg/cache/rbc-revs-v1
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=120
$ hg log -r 'branch(.)' -T '{rev} ' --debug
3 4 8 9 10 11 12 13 truncating cache/rbc-revs-v1 to 8
$ rm -f .hg/cache/branch* && hg head a -T '{rev}\n' --debug
5
truncating cache/rbc-revs-v1 to 104
$ f --size --hexdump --bytes=16 .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=120
0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
cache is updated when committing
$ hg branch i-will-regret-this
marked working directory as branch i-will-regret-this
$ hg ci -m regrets
$ f --size .hg/cache/rbc-*
.hg/cache/rbc-names-v1: size=106
.hg/cache/rbc-revs-v1: size=128
update after rollback - the cache will be correct but rbc-names will will still
contain the branch name even though it no longer is used
$ hg up -qr '.^'
$ hg rollback -qf
$ f --size --hexdump .hg/cache/rbc-*
.hg/cache/rbc-names-v1: size=106
0000: 64 65 66 61 75 6c 74 00 61 00 62 00 63 00 61 20 |default.a.b.c.a |
0010: 62 72 61 6e 63 68 20 6e 61 6d 65 20 6d 75 63 68 |branch name much|
0020: 20 6c 6f 6e 67 65 72 20 74 68 61 6e 20 74 68 65 | longer than the|
0030: 20 64 65 66 61 75 6c 74 20 6a 75 73 74 69 66 69 | default justifi|
0040: 63 61 74 69 6f 6e 20 75 73 65 64 20 62 79 20 62 |cation used by b|
0050: 72 61 6e 63 68 65 73 00 69 2d 77 69 6c 6c 2d 72 |ranches.i-will-r|
0060: 65 67 72 65 74 2d 74 68 69 73 |egret-this|
.hg/cache/rbc-revs-v1: size=120
0000: 19 70 9c 5a 00 00 00 00 dd 6b 44 0d 00 00 00 01 |.p.Z.....kD.....|
0010: 88 1f e2 b9 00 00 00 01 ac 22 03 33 00 00 00 02 |.........".3....|
0020: ae e3 9c d1 00 00 00 02 d8 cb c6 1d 00 00 00 01 |................|
0030: 58 97 36 a2 00 00 00 03 10 ff 58 95 00 00 00 04 |X.6.......X.....|
0040: ee bb 94 44 00 00 00 02 5f 40 61 bb 00 00 00 02 |...D...._@a.....|
0050: bf be 84 1b 00 00 00 02 d3 f1 63 45 80 00 00 02 |..........cE....|
0060: e3 d4 9c 05 80 00 00 02 e2 3b 55 05 00 00 00 02 |.........;U.....|
0070: f8 94 c2 56 80 00 00 03 |...V....|
cache is updated/truncated when stripping - it is thus very hard to get in a
situation where the cache is out of sync and the hash check detects it
$ hg --config extensions.strip= strip -r tip --nob
$ f --size .hg/cache/rbc-revs*
.hg/cache/rbc-revs-v1: size=112
$ cd ..