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
============================================
Testing obsolescence markers push: Cases A.7
============================================
Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of
all changesets that requested to be "in sync" after the push (even if they are
already on both side).
This test belongs to a series of tests checking such set is properly computed
and applied. This does not tests "obsmarkers" discovery capabilities.
Category A: simple cases
TestCase 7: markers one non targeted common changeset
A.7 non targeted common changeset
=================================
.. {{{
.. ⇠◕ A
.. |
.. ● O
.. }}}
..
.. Markers exist from:
..
.. * Chain from A
..
.. Command run:
..
.. * hg push -r O
..
.. Expected exchange:
..
.. * ø
Setup
-----
$ . $TESTDIR/testlib/exchange-obsmarker-util.sh
Initial
$ setuprepos A.7
creating test repo for test case A.7
- pulldest
- main
- pushdest
cd into `main` and proceed with env setup
$ cd main
$ mkcommit A
$ hg push -q ../pushdest
$ hg push -q ../pulldest
$ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid 'desc(A)'`
1 new obsolescence markers
$ hg log -G --hidden
@ f5bc6836db60 (draft): A
|
o a9bdc8b26820 (public): O
$ inspect_obsmarkers
obsstore content
================
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
$ cd ..
$ cd ..
Actual Test
-----------------------------------
$ dotest A.7 O
## Running testcase A.7
# testing echange of "O" (a9bdc8b26820)
## initial state
# obstore: main
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
# obstore: pulldest
## pushing "O" from main to pushdest
pushing to pushdest
searching for changes
no changes found
## post push state
# obstore: main
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
# obstore: pulldest
## pulling "a9bdc8b26820" from main into pulldest
pulling from main
no changes found
## post pull state
# obstore: main
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
# obstore: pushdest
# obstore: pulldest