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
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ cat >> $HGRCPATH <<EOF
> [devel]
> remotefilelog.bg-wait=True
> EOF
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo z > z
$ hg commit -qAm x
$ echo x2 > x
$ echo y > y
$ hg commit -qAm y
$ echo w > w
$ rm z
$ hg commit -qAm w
$ hg bookmark foo
$ cd ..
# clone the repo
$ hgcloneshallow ssh://user@dummy/master shallow --noupdate
streaming all changes
2 files to transfer, 776 bytes of data (no-zstd !)
transferred 776 bytes in * seconds (*/sec) (glob) (no-zstd !)
2 files to transfer, 784 bytes of data (zstd !)
transferred 784 bytes in * seconds (* */sec) (glob) (zstd !)
searching for changes
no changes found
# Set the prefetchdays config to zero so that all commits are prefetched
# no matter what their creation date is. Also set prefetchdelay config
# to zero so that there is no delay between prefetches.
$ cd shallow
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> prefetchdays=0
> prefetchdelay=0
> EOF
$ cd ..
# prefetch a revision
$ cd shallow
$ hg prefetch -r 0
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg cat -r 0 x
x
# background prefetch on pull when configured
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> pullprefetch=bookmark()
> backgroundprefetch=True
> EOF
$ hg strip tip
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/6b4b6f66ef8c-b4b8bdaf-backup.hg (glob)
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ clearcache
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
updating bookmark foo
added 1 changesets with 0 changes to 0 files
new changesets 6b4b6f66ef8c
(run 'hg update' to get a working copy)
prefetching file contents
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/ef95c5376f34698742fe34f315fd82136f8f68c0
$TESTTMP/hgcache/master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca
$TESTTMP/hgcache/master/af/f024fe4ab0fece4091de044c58c9ae4233383a/bb6ccd5dceaa5e9dc220e0dad65e051b94f69a2c
$TESTTMP/hgcache/repos
# background prefetch with repack on pull when configured
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> backgroundrepack=True
> EOF
$ hg strip tip
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/6b4b6f66ef8c-b4b8bdaf-backup.hg (glob)
$ clearcache
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
updating bookmark foo
added 1 changesets with 0 changes to 0 files
new changesets 6b4b6f66ef8c
(run 'hg update' to get a working copy)
prefetching file contents
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/6e8633deba6e544e5f8edbd7b996d6e31a2c42ae.histidx
$TESTTMP/hgcache/master/packs/6e8633deba6e544e5f8edbd7b996d6e31a2c42ae.histpack
$TESTTMP/hgcache/master/packs/8ce5ab3745465ab83bba30a7b9c295e0c8404652.dataidx
$TESTTMP/hgcache/master/packs/8ce5ab3745465ab83bba30a7b9c295e0c8404652.datapack
$TESTTMP/hgcache/repos
# background prefetch with repack on update when wcprevset configured
$ clearcache
$ hg up -r 0
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0
$TESTTMP/hgcache/master/39/5df8f7c51f007019cb30201c49e884b46b92fa/69a1b67522704ec122181c0890bd16e9d3e7516a
$TESTTMP/hgcache/repos
$ hg up -r 1
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=.::
> EOF
$ clearcache
$ hg up -r 0
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
* files fetched over * fetches - (* misses, 0.00% hit ratio) over *s (glob)
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that file 'w' was prefetched - it was not part of the update operation and therefore
# could only be downloaded by the background prefetch
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# background prefetch with repack on commit when wcprevset configured
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> bgprefetchrevs=0::
> EOF
$ clearcache
$ find $CACHEDIR -type f | sort
$ echo b > b
.. The following output line about files fetches is globed because it is
.. flaky, the core the test is checked when checking the cache dir, so
.. hopefully this flakyness is not hiding any actual bug.
$ hg commit -qAm b
* files fetched over 1 fetches - (* misses, 0.00% hit ratio) over *s (glob) (?)
$ hg bookmark temporary
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that file 'w' was prefetched - it was not part of the commit operation and therefore
# could only be downloaded by the background prefetch
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# background prefetch with repack on rebase when wcprevset configured
$ hg up -r 2
3 files updated, 0 files merged, 2 files removed, 0 files unresolved
(leaving bookmark temporary)
$ clearcache
$ find $CACHEDIR -type f | sort
.. The following output line about files fetches is globed because it is
.. flaky, the core the test is checked when checking the cache dir, so
.. hopefully this flakyness is not hiding any actual bug.
$ hg rebase -s temporary -d foo
rebasing 3:d9cf06e3b5b6 temporary tip "b"
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/d9cf06e3b5b6-e5c3dc63-rebase.hg
? files fetched over ? fetches - (? misses, 0.00% hit ratio) over *s (glob)
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that file 'y' was prefetched - it was not part of the rebase operation and therefore
# could only be downloaded by the background prefetch
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# Check that foregound prefetch with no arguments blocks until background prefetches finish
$ hg up -r 3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ clearcache
$ hg prefetch --repack --config ui.timeout.warn=-1
(running background incremental repack)
* files fetched over 1 fetches - (* misses, 0.00% hit ratio) over *s (glob) (?)
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that files were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# Check that foreground prefetch fetches revs specified by '. + draft() + bgprefetchrevs + pullprefetch'
$ clearcache
$ hg prefetch --repack --config ui.timeout.warn=-1
(running background incremental repack)
* files fetched over 1 fetches - (* misses, 0.00% hit ratio) over *s (glob) (?)
$ find $CACHEDIR -type f | sort
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histidx
$TESTTMP/hgcache/master/packs/8f1443d44e57fec96f72fb2412e01d2818767ef2.histpack
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.dataidx
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407.datapack
$TESTTMP/hgcache/repos
# Ensure that files were prefetched
$ hg debugdatapack `ls -ct $TESTTMP/hgcache/master/packs/*.datapack | head -n 1`
$TESTTMP/hgcache/master/packs/f4d50848e0b465e9bfd2875f213044c06cfd7407:
w:
Node Delta Base Delta Length Blob Size
bb6ccd5dceaa 000000000000 2 2
Total: 2 2 (0.0% bigger)
x:
Node Delta Base Delta Length Blob Size
ef95c5376f34 000000000000 3 3
1406e7411862 ef95c5376f34 14 2
Total: 17 5 (240.0% bigger)
y:
Node Delta Base Delta Length Blob Size
076f5e2225b3 000000000000 2 2
Total: 2 2 (0.0% bigger)
z:
Node Delta Base Delta Length Blob Size
69a1b6752270 000000000000 2 2
Total: 2 2 (0.0% bigger)
# Test that if data was prefetched and repacked we dont need to prefetch it again
# It ensures that Mercurial looks not only in loose files but in packs as well
$ hg prefetch --repack
(running background incremental repack)