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
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert=" >> $HGRCPATH
$ glog()
> {
> hg log -G --template '{rev}:{node|short} "{desc|firstline}"\
> files: {files}\n' "$@"
> }
$ hg init repo1
$ cd repo1
$ echo a > a
$ hg ci -Am adda
adding a
$ echo b > b
$ echo a >> a
$ hg ci -Am addb
adding b
$ PARENTID1=`hg id --debug -i`
$ echo c > c
$ hg ci -Am addc
adding c
$ PARENTID2=`hg id --debug -i`
$ cd ..
$ glog -R repo1
@ 2:e55c719b85b6 "addc" files: c
|
o 1:6d4c2037ddc2 "addb" files: a b
|
o 0:07f494440405 "adda" files: a
$ hg init repo2
$ cd repo2
$ echo b > a
$ echo d > d
$ hg ci -Am addaandd
adding a
adding d
$ INVALIDID1=afd12345af
$ INVALIDID2=28173x36ddd1e67bf7098d541130558ef5534a86
$ CHILDID1=`hg id --debug -i`
$ echo d >> d
$ hg ci -Am changed
$ CHILDID2=`hg id --debug -i`
$ echo e > e
$ hg ci -Am adde
adding e
$ cd ..
$ glog -R repo2
@ 2:a39b65753b0a "adde" files: e
|
o 1:e4ea00df9189 "changed" files: d
|
o 0:527cdedf31fb "addaandd" files: a d
test invalid splicemap1
$ cat > splicemap <<EOF
> $CHILDID2
> EOF
$ hg convert --splicemap splicemap repo2 repo1
abort: syntax error in splicemap(1): child parent1[,parent2] expected
[255]
test invalid splicemap2
$ cat > splicemap <<EOF
> $CHILDID2 $PARENTID1, $PARENTID2, $PARENTID2
> EOF
$ hg convert --splicemap splicemap repo2 repo1
abort: syntax error in splicemap(1): child parent1[,parent2] expected
[255]
test invalid splicemap3
$ cat > splicemap <<EOF
> $INVALIDID1 $INVALIDID2
> EOF
$ hg convert --splicemap splicemap repo2 repo1
abort: splicemap entry afd12345af is not a valid revision identifier
[255]
splice repo2 on repo1
$ cat > splicemap <<EOF
> $CHILDID1 $PARENTID1
> $CHILDID2 $PARENTID2,$CHILDID1
>
> EOF
$ cat splicemap
527cdedf31fbd5ea708aa14eeecf53d4676f38db 6d4c2037ddc2cb2627ac3a244ecce35283268f8e
e4ea00df91897da3079a10fab658c1eddba6617b e55c719b85b60e5102fac26110ba626e7cb6b7dc,527cdedf31fbd5ea708aa14eeecf53d4676f38db
$ hg clone repo1 target1
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg convert --splicemap splicemap repo2 target1
scanning source...
sorting...
converting...
2 addaandd
spliced in 6d4c2037ddc2cb2627ac3a244ecce35283268f8e as parents of 527cdedf31fbd5ea708aa14eeecf53d4676f38db
1 changed
spliced in e55c719b85b60e5102fac26110ba626e7cb6b7dc and 527cdedf31fbd5ea708aa14eeecf53d4676f38db as parents of e4ea00df91897da3079a10fab658c1eddba6617b
0 adde
$ glog -R target1
o 5:16bc847b02aa "adde" files: e
|
o 4:e30e4fee3418 "changed" files: d
|\
| o 3:e673348c3a3c "addaandd" files: a d
| |
@ | 2:e55c719b85b6 "addc" files: c
|/
o 1:6d4c2037ddc2 "addb" files: a b
|
o 0:07f494440405 "adda" files: a
Test splicemap and conversion order
$ hg init ordered
$ cd ordered
$ echo a > a
$ hg ci -Am adda
adding a
$ hg branch branch
marked working directory as branch branch
(branches are permanent and global, did you want a bookmark?)
$ echo a >> a
$ hg ci -Am changea
$ echo a >> a
$ hg ci -Am changeaagain
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo b > b
$ hg ci -Am addb
adding b
We want 2 to depend on 1 and 3. Since 3 is always converted after 2,
the bug should be exhibited with all conversion orders.
$ cat > ../splicemap <<EOF
> `(hg id -r 2 -i --debug)` `(hg id -r 1 -i --debug)`, `(hg id -r 3 -i --debug)`
> EOF
$ cd ..
$ cat splicemap
7c364e7fa7d70ae525610c016317ed717b519d97 717d54d67e6c31fd75ffef2ff3042bdd98418437, 102a90ea7b4a3361e4082ed620918c261189a36a
Test regular conversion
$ hg convert --splicemap splicemap ordered ordered-hg1
initializing destination ordered-hg1 repository
scanning source...
sorting...
converting...
3 adda
2 changea
1 addb
0 changeaagain
spliced in 717d54d67e6c31fd75ffef2ff3042bdd98418437 and 102a90ea7b4a3361e4082ed620918c261189a36a as parents of 7c364e7fa7d70ae525610c016317ed717b519d97
$ glog -R ordered-hg1
o 3:4cb04b9afbf2 "changeaagain" files: a
|\
| o 2:102a90ea7b4a "addb" files: b
| |
o | 1:717d54d67e6c "changea" files: a
|/
o 0:07f494440405 "adda" files: a
Test conversion with parent revisions already in dest, using source
and destination identifiers. Test unknown splicemap target.
$ hg convert -r1 ordered ordered-hg2
initializing destination ordered-hg2 repository
scanning source...
sorting...
converting...
1 adda
0 changea
$ hg convert -r3 ordered ordered-hg2
scanning source...
sorting...
converting...
0 addb
$ cat > splicemap <<EOF
> `(hg -R ordered id -r 2 -i --debug)` \
> `(hg -R ordered-hg2 id -r 1 -i --debug)`,\
> `(hg -R ordered-hg2 id -r 2 -i --debug)`
> deadbeef102a90ea7b4a3361e4082ed620918c26 deadbeef102a90ea7b4a3361e4082ed620918c27
> EOF
$ hg convert --splicemap splicemap ordered ordered-hg2
scanning source...
splice map revision deadbeef102a90ea7b4a3361e4082ed620918c26 is not being converted, ignoring
sorting...
converting...
0 changeaagain
spliced in 717d54d67e6c31fd75ffef2ff3042bdd98418437 and 102a90ea7b4a3361e4082ed620918c261189a36a as parents of 7c364e7fa7d70ae525610c016317ed717b519d97
$ glog -R ordered-hg2
o 3:4cb04b9afbf2 "changeaagain" files: a
|\
| o 2:102a90ea7b4a "addb" files: b
| |
o | 1:717d54d67e6c "changea" files: a
|/
o 0:07f494440405 "adda" files: a
Test empty conversion
$ hg convert --splicemap splicemap ordered ordered-hg2
scanning source...
splice map revision deadbeef102a90ea7b4a3361e4082ed620918c26 is not being converted, ignoring
sorting...
converting...
Test clonebranches
$ hg --config convert.hg.clonebranches=true convert \
> --splicemap splicemap ordered ordered-hg3
initializing destination ordered-hg3 repository
scanning source...
abort: revision 717d54d67e6c31fd75ffef2ff3042bdd98418437 not found in destination repository (lookups with clonebranches=true are not implemented)
[255]
Test invalid dependency
$ cat > splicemap <<EOF
> `(hg -R ordered id -r 2 -i --debug)` \
> deadbeef102a90ea7b4a3361e4082ed620918c26,\
> `(hg -R ordered-hg2 id -r 2 -i --debug)`
> EOF
$ hg convert --splicemap splicemap ordered ordered-hg4
initializing destination ordered-hg4 repository
scanning source...
abort: unknown splice map parent: deadbeef102a90ea7b4a3361e4082ed620918c26
[255]