filemerge: add support for partial conflict resolution by external tool
A common class of merge conflicts is in imports/#includes/etc. It's
relatively easy to write a tool that can resolve these conflicts,
perhaps by naively just unioning the statements and leaving any
cleanup to other tools to do later [1]. Such specialized tools cannot
generally resolve all conflicts in a file, of course. Let's therefore
call them "partial merge tools". Note that the internal simplemerge
algorithm is such a partial merge tool - one that only resolves
trivial "conflicts" where one side is unchanged or both sides change
in the same way.
One can also imagine having smarter language-aware partial tools that
merge the AST. It may be useful for such tools to interactively let
the user resolve any conflicts it can't resolve itself. However,
having the option of implementing it as a partial merge tool means
that the developer doesn't *need* to create a UI for it. Instead, the
user can resolve any remaining conflicts with their regular merge tool
(e.g. `:merge3` or `meld).
We don't currently have a way to let the user define such partial
merge tools. That's what this patch addresses. It lets the user
configure partial merge tools to run. Each tool can be configured to
run only on files matching certain patterns (e.g. "*.py"). The tool
takes three inputs (local, base, other) and resolves conflicts by
updating these in place. For example, let's say the inputs are these:
base:
```
import sys
def main():
print('Hello')
```
local:
```
import os
import sys
def main():
print('Hi')
```
other:
```
import re
import sys
def main():
print('Howdy')
```
A partial merge tool could now resolve the conflicting imports by
replacing the import statements in *all* files by the following
snippet, while leaving the remainder of the files unchanged.
```
import os
import re
import sys
```
As a result, simplemerge and any regular merge tool that runs after
the partial merge tool(s) will consider the imports to be
non-conflicting and will only present the conflict in `main()` to the
user.
Differential Revision: https://phab.mercurial-scm.org/D12356
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
> mq=
>
> [mq]
> plain=true
>
> [alias]
> tglog = log -G --template "{rev}: {node|short} '{desc}' tags: {tags}\n"
> EOF
$ hg init a
$ cd a
$ hg qinit -c
$ echo c1 > f
$ hg add f
$ hg ci -m C1
$ echo r1 > f
$ hg ci -m R1
$ hg up -q 0
$ hg qnew f.patch -d '1 0'
$ echo mq1 > f
$ hg qref -m P0
$ hg qnew f2.patch
$ echo mq2 > f
$ hg qref -m P1 -d '2 0'
$ hg tglog
@ 3: 929394423cd3 'P1' tags: f2.patch qtip tip
|
o 2: 3504f44bffc0 'P0' tags: f.patch qbase
|
| o 1: bac9ed9960d8 'R1' tags:
|/
o 0: 36f36ddbca61 'C1' tags: qparent
Rebase - try to rebase on an applied mq patch:
$ hg rebase -s 1 -d 3
abort: cannot rebase onto an applied mq patch
[20]
Rebase - same thing, but mq patch is default dest:
$ hg up -q 1
$ hg rebase
abort: cannot rebase onto an applied mq patch
[20]
$ hg up -q qtip
Rebase - generate a conflict:
$ hg rebase -s 2 -d 1
rebasing 2:3504f44bffc0 f.patch qbase "P0"
merging f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
Fix the 1st conflict:
$ echo mq1r1 > f
$ hg resolve -m f
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase -c
rebasing 2:3504f44bffc0 f.patch qbase "P0"
rebasing 3:929394423cd3 f2.patch qtip tip "P1"
merging f
warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
[240]
Fix the 2nd conflict:
$ echo mq1r1mq2 > f
$ hg resolve -m f
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase -c
already rebased 2:3504f44bffc0 f.patch qbase "P0" as ebe9914c0d1c
rebasing 3:929394423cd3 f2.patch qtip "P1"
saved backup bundle to $TESTTMP/a/.hg/strip-backup/3504f44bffc0-30595b40-rebase.hg
$ hg tglog
@ 3: 462012cf340c 'P1' tags: f2.patch qtip tip
|
o 2: ebe9914c0d1c 'P0' tags: f.patch qbase
|
o 1: bac9ed9960d8 'R1' tags: qparent
|
o 0: 36f36ddbca61 'C1' tags:
$ hg up -q qbase
$ cat f
mq1r1
$ cat .hg/patches/f.patch
# HG changeset patch
# User test
# Date 1 0
# Thu Jan 01 00:00:01 1970 +0000
# Node ID ebe9914c0d1c3f60096e952fa4dbb3d377dea3ab
# Parent bac9ed9960d8992bcad75864a879fa76cadaf1b0
P0
diff -r bac9ed9960d8 -r ebe9914c0d1c f
--- a/f Thu Jan 01 00:00:00 1970 +0000
+++ b/f Thu Jan 01 00:00:01 1970 +0000
@@ -1,1 +1,1 @@
-r1
+mq1r1
Update to qtip:
$ hg up -q qtip
$ cat f
mq1r1mq2
$ cat .hg/patches/f2.patch
# HG changeset patch
# User test
# Date 2 0
# Thu Jan 01 00:00:02 1970 +0000
# Node ID 462012cf340c97d44d62377c985a423f6bb82f07
# Parent ebe9914c0d1c3f60096e952fa4dbb3d377dea3ab
P1
diff -r ebe9914c0d1c -r 462012cf340c f
--- a/f Thu Jan 01 00:00:01 1970 +0000
+++ b/f Thu Jan 01 00:00:02 1970 +0000
@@ -1,1 +1,1 @@
-mq1r1
+mq1r1mq2
Adding one git-style patch and one normal:
$ hg qpop -a
popping f2.patch
popping f.patch
patch queue now empty
$ rm -fr .hg/patches
$ hg qinit -c
$ hg up -q 0
$ hg qnew --git f_git.patch -d '3 0'
$ echo mq1 > p
$ hg add p
$ hg qref --git -m 'P0 (git)'
$ hg qnew f.patch -d '4 0'
$ echo mq2 > p
$ hg qref -m P1
$ hg qci -m 'save patch state'
$ hg qseries -s
f_git.patch: P0 (git)
f.patch: P1
$ hg -R .hg/patches manifest
.hgignore
f.patch
f_git.patch
series
$ cat .hg/patches/f_git.patch
Date: 3 0
P0 (git)
diff --git a/p b/p
new file mode 100644
--- /dev/null
+++ b/p
@@ -0,0 +1,1 @@
+mq1
$ cat .hg/patches/f.patch
Date: 4 0
P1
diff -r ???????????? p (glob)
--- a/p ??? ??? ?? ??:??:?? ???? ????? (glob)
+++ b/p ??? ??? ?? ??:??:?? ???? ????? (glob)
@@ -1,1 +1,1 @@
-mq1
+mq2
Rebase the applied mq patches:
$ hg rebase -s 2 -d 1
rebasing 2:0c587ffcb480 f_git.patch qbase "P0 (git)"
rebasing 3:c7f18665e4bc f.patch qtip tip "P1"
saved backup bundle to $TESTTMP/a/.hg/strip-backup/0c587ffcb480-0ea5695f-rebase.hg
$ hg qci -m 'save patch state'
$ hg qseries -s
f_git.patch: P0 (git)
f.patch: P1
$ hg -R .hg/patches manifest
.hgignore
f.patch
f_git.patch
series
$ cat .hg/patches/f_git.patch
# HG changeset patch
# User test
# Date 3 0
# Thu Jan 01 00:00:03 1970 +0000
# Node ID 12d9f6a3bbe560dee50c7c454d434add7fb8e837
# Parent bac9ed9960d8992bcad75864a879fa76cadaf1b0
P0 (git)
diff --git a/p b/p
new file mode 100644
--- /dev/null
+++ b/p
@@ -0,0 +1,1 @@
+mq1
$ cat .hg/patches/f.patch
# HG changeset patch
# User test
# Date 4 0
# Thu Jan 01 00:00:04 1970 +0000
# Node ID c77a2661c64c60d82f63c4f7aefd95b3a948a557
# Parent 12d9f6a3bbe560dee50c7c454d434add7fb8e837
P1
diff -r 12d9f6a3bbe5 -r c77a2661c64c p
--- a/p Thu Jan 01 00:00:03 1970 +0000
+++ b/p Thu Jan 01 00:00:04 1970 +0000
@@ -1,1 +1,1 @@
-mq1
+mq2
$ cd ..
Rebase with guards
$ hg init foo
$ cd foo
$ echo a > a
$ hg ci -Am a
adding a
Create mq repo with guarded patches foo and bar and empty patch:
$ hg qinit
$ echo guarded > guarded
$ hg add guarded
$ hg qnew guarded
$ hg qnew empty-important -m 'important commit message' -d '1 0'
$ echo bar > bar
$ hg add bar
$ hg qnew bar -d '2 0'
$ echo foo > foo
$ hg add foo
$ hg qnew foo
$ hg qpop -a
popping foo
popping bar
popping empty-important
popping guarded
patch queue now empty
$ hg qguard guarded +guarded
$ hg qguard bar +baz
$ hg qguard foo +baz
$ hg qselect baz
number of unguarded, unapplied patches has changed from 1 to 3
$ hg qpush bar
applying empty-important
patch empty-important is empty
applying bar
now at: bar
$ hg qguard -l
guarded: +guarded
empty-important: unguarded
bar: +baz
foo: +baz
$ hg tglog
@ 2: 4f44b861d38c 'imported patch bar' tags: bar qtip tip
|
o 1: 0aaf4c3af7eb 'important commit message' tags: empty-important qbase
|
o 0: cb9a9f314b8b 'a' tags: qparent
Create new head to rebase bar onto:
$ hg up -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo b > b
$ hg add b
$ hg ci -m b
created new head
$ hg up -C 2
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo a >> a
$ hg qref
$ hg tglog
@ 3: d526d4536ed6 '[mq]: bar' tags: bar qtip tip
|
| o 2: d2ae7f538514 'b' tags:
| |
o | 1: 0aaf4c3af7eb 'important commit message' tags: empty-important qbase
|/
o 0: cb9a9f314b8b 'a' tags: qparent
Rebase bar (make sure series order is preserved and empty-important also is
removed from the series):
$ hg qseries
guarded
empty-important
bar
foo
$ [ -f .hg/patches/empty-important ]
$ hg -q rebase -d 2
note: not rebasing 1:0aaf4c3af7eb empty-important qbase "important commit message", its destination already has all its changes
$ hg qseries
guarded
bar
foo
$ [ -f .hg/patches/empty-important ]
[1]
$ hg qguard -l
guarded: +guarded
bar: +baz
foo: +baz
$ hg tglog
@ 2: 477d948bb2af '[mq]: bar' tags: bar qbase qtip tip
|
o 1: d2ae7f538514 'b' tags: qparent
|
o 0: cb9a9f314b8b 'a' tags:
$ cd ..