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
Create configuration
$ echo "[ui]" >> $HGRCPATH
$ echo "interactive=true" >> $HGRCPATH
help qrefresh (no record)
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg help qrefresh
hg qrefresh [-I] [-X] [-e] [-m TEXT] [-l FILE] [-s] [FILE]...
update the current patch
If any file patterns are provided, the refreshed patch will contain only
the modifications that match those patterns; the remaining modifications
will remain in the working directory.
If -s/--short is specified, files currently included in the patch will be
refreshed just like matched files and remain in the patch.
If -e/--edit is specified, Mercurial will start your configured editor for
you to enter a message. In case qrefresh fails, you will find a backup of
your message in ".hg/last-message.txt".
hg add/remove/copy/rename work as usual, though you might want to use git-
style patches (-g/--git or [diff] git=1) to track copies and renames. See
the diffs help topic for more information on the git diff format.
Returns 0 on success.
options ([+] can be repeated):
-e --edit invoke editor on commit messages
-g --git use git extended diff format
-s --short refresh only files already in the patch and
specified files
-U --currentuser add/update author field in patch with current user
-u --user USER add/update author field in patch with given user
-D --currentdate add/update date field in patch with current date
-d --date DATE add/update date field in patch with given date
-I --include PATTERN [+] include names matching the given patterns
-X --exclude PATTERN [+] exclude names matching the given patterns
-m --message TEXT use text as commit message
-l --logfile FILE read commit message from file
(some details hidden, use --verbose to show complete help)
help qrefresh (record)
$ echo "record=" >> $HGRCPATH
$ hg help qrefresh
hg qrefresh [-I] [-X] [-e] [-m TEXT] [-l FILE] [-s] [FILE]...
update the current patch
If any file patterns are provided, the refreshed patch will contain only
the modifications that match those patterns; the remaining modifications
will remain in the working directory.
If -s/--short is specified, files currently included in the patch will be
refreshed just like matched files and remain in the patch.
If -e/--edit is specified, Mercurial will start your configured editor for
you to enter a message. In case qrefresh fails, you will find a backup of
your message in ".hg/last-message.txt".
hg add/remove/copy/rename work as usual, though you might want to use git-
style patches (-g/--git or [diff] git=1) to track copies and renames. See
the diffs help topic for more information on the git diff format.
Returns 0 on success.
options ([+] can be repeated):
-e --edit invoke editor on commit messages
-g --git use git extended diff format
-s --short refresh only files already in the patch and
specified files
-U --currentuser add/update author field in patch with current user
-u --user USER add/update author field in patch with given user
-D --currentdate add/update date field in patch with current date
-d --date DATE add/update date field in patch with given date
-I --include PATTERN [+] include names matching the given patterns
-X --exclude PATTERN [+] exclude names matching the given patterns
-m --message TEXT use text as commit message
-l --logfile FILE read commit message from file
-i --interactive interactively select changes to refresh
(some details hidden, use --verbose to show complete help)
$ hg init a
$ cd a
Base commit
$ cat > 1.txt <<EOF
> 1
> 2
> 3
> 4
> 5
> EOF
$ cat > 2.txt <<EOF
> a
> b
> c
> d
> e
> f
> EOF
$ mkdir dir
$ cat > dir/a.txt <<EOF
> hello world
>
> someone
> up
> there
> loves
> me
> EOF
$ hg add 1.txt 2.txt dir/a.txt
$ hg commit -m aaa
$ hg qrecord --config ui.interactive=false patch
abort: running non-interactively, use qnew instead
[10]
$ hg qnew -i --config ui.interactive=false patch
abort: running non-interactively
[10]
$ hg qnew -d '0 0' patch
Changing files
$ sed -e 's/2/2 2/;s/4/4 4/' 1.txt > 1.txt.new
$ sed -e 's/b/b b/' 2.txt > 2.txt.new
$ sed -e 's/hello world/hello world!/' dir/a.txt > dir/a.txt.new
$ mv -f 1.txt.new 1.txt
$ mv -f 2.txt.new 2.txt
$ mv -f dir/a.txt.new dir/a.txt
Whole diff
$ hg diff --nodates
diff -r ed27675cb5df 1.txt
--- a/1.txt
+++ b/1.txt
@@ -1,5 +1,5 @@
1
-2
+2 2
3
-4
+4 4
5
diff -r ed27675cb5df 2.txt
--- a/2.txt
+++ b/2.txt
@@ -1,5 +1,5 @@
a
-b
+b b
c
d
e
diff -r ed27675cb5df dir/a.txt
--- a/dir/a.txt
+++ b/dir/a.txt
@@ -1,4 +1,4 @@
-hello world
+hello world!
someone
up
partial qrefresh
$ hg qrefresh -i --config ui.interactive=false
abort: running non-interactively
[10]
$ hg qrefresh -i -d '0 0' <<EOF
> y
> y
> n
> y
> y
> n
> EOF
diff --git a/1.txt b/1.txt
2 hunks, 2 lines changed
examine changes to '1.txt'?
(enter ? for help) [Ynesfdaq?] y
@@ -1,3 +1,3 @@
1
-2
+2 2
3
record change 1/4 to '1.txt'?
(enter ? for help) [Ynesfdaq?] y
@@ -3,3 +3,3 @@
3
-4
+4 4
5
record change 2/4 to '1.txt'?
(enter ? for help) [Ynesfdaq?] n
diff --git a/2.txt b/2.txt
1 hunks, 1 lines changed
examine changes to '2.txt'?
(enter ? for help) [Ynesfdaq?] y
@@ -1,5 +1,5 @@
a
-b
+b b
c
d
e
record change 3/4 to '2.txt'?
(enter ? for help) [Ynesfdaq?] y
diff --git a/dir/a.txt b/dir/a.txt
1 hunks, 1 lines changed
examine changes to 'dir/a.txt'?
(enter ? for help) [Ynesfdaq?] n
After partial qrefresh 'tip'
$ hg tip -p
changeset: 1:0738af1a8211
tag: patch
tag: qbase
tag: qtip
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: [mq]: patch
diff -r 1fd39ab63a33 -r 0738af1a8211 1.txt
--- a/1.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/1.txt Thu Jan 01 00:00:00 1970 +0000
@@ -1,5 +1,5 @@
1
-2
+2 2
3
4
5
diff -r 1fd39ab63a33 -r 0738af1a8211 2.txt
--- a/2.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/2.txt Thu Jan 01 00:00:00 1970 +0000
@@ -1,5 +1,5 @@
a
-b
+b b
c
d
e
After partial qrefresh 'diff'
$ hg diff --nodates
diff -r 0738af1a8211 1.txt
--- a/1.txt
+++ b/1.txt
@@ -1,5 +1,5 @@
1
2 2
3
-4
+4 4
5
diff -r 0738af1a8211 dir/a.txt
--- a/dir/a.txt
+++ b/dir/a.txt
@@ -1,4 +1,4 @@
-hello world
+hello world!
someone
up
qrefresh interactively everything else
$ hg qrefresh -i -d '0 0' <<EOF
> y
> y
> y
> y
> EOF
diff --git a/1.txt b/1.txt
1 hunks, 1 lines changed
examine changes to '1.txt'?
(enter ? for help) [Ynesfdaq?] y
@@ -1,5 +1,5 @@
1
2 2
3
-4
+4 4
5
record change 1/2 to '1.txt'?
(enter ? for help) [Ynesfdaq?] y
diff --git a/dir/a.txt b/dir/a.txt
1 hunks, 1 lines changed
examine changes to 'dir/a.txt'?
(enter ? for help) [Ynesfdaq?] y
@@ -1,4 +1,4 @@
-hello world
+hello world!
someone
up
record change 2/2 to 'dir/a.txt'?
(enter ? for help) [Ynesfdaq?] y
After final qrefresh 'tip'
$ hg tip -p
changeset: 1:2c3f66afeed9
tag: patch
tag: qbase
tag: qtip
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: [mq]: patch
diff -r 1fd39ab63a33 -r 2c3f66afeed9 1.txt
--- a/1.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/1.txt Thu Jan 01 00:00:00 1970 +0000
@@ -1,5 +1,5 @@
1
-2
+2 2
3
-4
+4 4
5
diff -r 1fd39ab63a33 -r 2c3f66afeed9 2.txt
--- a/2.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/2.txt Thu Jan 01 00:00:00 1970 +0000
@@ -1,5 +1,5 @@
a
-b
+b b
c
d
e
diff -r 1fd39ab63a33 -r 2c3f66afeed9 dir/a.txt
--- a/dir/a.txt Thu Jan 01 00:00:00 1970 +0000
+++ b/dir/a.txt Thu Jan 01 00:00:00 1970 +0000
@@ -1,4 +1,4 @@
-hello world
+hello world!
someone
up
After qrefresh 'diff'
$ hg diff --nodates
$ cd ..