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 rhg
$ NO_FALLBACK="env RHG_ON_UNSUPPORTED=abort"
Unimplemented command
$ $NO_FALLBACK rhg unimplemented-command
unsupported feature: error: Found argument 'unimplemented-command' which wasn't expected, or isn't valid in this context
USAGE:
rhg [OPTIONS] <SUBCOMMAND>
For more information try --help
[252]
$ rhg unimplemented-command --config rhg.on-unsupported=abort-silent
[252]
Finding root
$ $NO_FALLBACK rhg root
abort: no repository found in '$TESTTMP' (.hg not found)!
[255]
$ hg init repository
$ cd repository
$ $NO_FALLBACK rhg root
$TESTTMP/repository
Reading and setting configuration
$ echo "[ui]" >> $HGRCPATH
$ echo "username = user1" >> $HGRCPATH
$ $NO_FALLBACK rhg config ui.username
user1
$ echo "[ui]" >> .hg/hgrc
$ echo "username = user2" >> .hg/hgrc
$ $NO_FALLBACK rhg config ui.username
user2
$ $NO_FALLBACK rhg --config ui.username=user3 config ui.username
user3
Unwritable file descriptor
$ $NO_FALLBACK rhg root > /dev/full
abort: No space left on device (os error 28)
[255]
Deleted repository
$ rm -rf `pwd`
$ $NO_FALLBACK rhg root
abort: error getting current working directory: $ENOENT$
[255]
Listing tracked files
$ cd $TESTTMP
$ hg init repository
$ cd repository
$ for i in 1 2 3; do
> echo $i >> file$i
> hg add file$i
> done
> hg commit -m "commit $i" -q
Listing tracked files from root
$ $NO_FALLBACK rhg files
file1
file2
file3
Listing tracked files from subdirectory
$ mkdir -p path/to/directory
$ cd path/to/directory
$ $NO_FALLBACK rhg files
../../../file1
../../../file2
../../../file3
Listing tracked files through broken pipe
$ $NO_FALLBACK rhg files | head -n 1
../../../file1
Debuging data in inline index
$ cd $TESTTMP
$ rm -rf repository
$ hg init repository
$ cd repository
$ for i in 1 2 3 4 5 6; do
> echo $i >> file-$i
> hg add file-$i
> hg commit -m "Commit $i" -q
> done
$ $NO_FALLBACK rhg debugdata -c 2
8d0267cb034247ebfa5ee58ce59e22e57a492297
test
0 0
file-3
Commit 3 (no-eol)
$ $NO_FALLBACK rhg debugdata -m 2
file-1\x00b8e02f6433738021a065f94175c7cd23db5f05be (esc)
file-2\x005d9299349fc01ddd25d0070d149b124d8f10411e (esc)
file-3\x002661d26c649684b482d10f91960cc3db683c38b4 (esc)
Debuging with full node id
$ $NO_FALLBACK rhg debugdata -c `hg log -r 0 -T '{node}'`
d1d1c679d3053e8926061b6f45ca52009f011e3f
test
0 0
file-1
Commit 1 (no-eol)
Specifying revisions by changeset ID
$ hg log -T '{node}\n'
c6ad58c44207b6ff8a4fbbca7045a5edaa7e908b
d654274993d0149eecc3cc03214f598320211900
f646af7e96481d3a5470b695cf30ad8e3ab6c575
cf8b83f14ead62b374b6e91a0e9303b85dfd9ed7
91c6f6e73e39318534dc415ea4e8a09c99cd74d6
6ae9681c6d30389694d8701faf24b583cf3ccafe
$ $NO_FALLBACK rhg files -r cf8b83
file-1
file-2
file-3
$ $NO_FALLBACK rhg cat -r cf8b83 file-2
2
$ $NO_FALLBACK rhg cat --rev cf8b83 file-2
2
$ $NO_FALLBACK rhg cat -r c file-2
abort: ambiguous revision identifier: c
[255]
$ $NO_FALLBACK rhg cat -r d file-2
2
$ $NO_FALLBACK rhg cat -r 0000 file-2
file-2: no such file in rev 000000000000
[1]
Cat files
$ cd $TESTTMP
$ rm -rf repository
$ hg init repository
$ cd repository
$ echo "original content" > original
$ hg add original
$ hg commit -m "add original" original
Without `--rev`
$ $NO_FALLBACK rhg cat original
original content
With `--rev`
$ $NO_FALLBACK rhg cat -r 0 original
original content
Cat copied file should not display copy metadata
$ hg copy original copy_of_original
$ hg commit -m "add copy of original"
$ $NO_FALLBACK rhg cat original
original content
$ $NO_FALLBACK rhg cat -r 1 copy_of_original
original content
Fallback to Python
$ $NO_FALLBACK rhg cat original --exclude="*.rs"
unsupported feature: error: Found argument '--exclude' which wasn't expected, or isn't valid in this context
USAGE:
rhg cat [OPTIONS] <FILE>...
For more information try --help
[252]
$ rhg cat original --exclude="*.rs"
original content
$ (unset RHG_FALLBACK_EXECUTABLE; rhg cat original --exclude="*.rs")
abort: 'rhg.on-unsupported=fallback' without 'rhg.fallback-executable' set.
[255]
$ (unset RHG_FALLBACK_EXECUTABLE; rhg cat original)
original content
$ rhg cat original --exclude="*.rs" --config rhg.fallback-executable=false
[1]
$ rhg cat original --exclude="*.rs" --config rhg.fallback-executable=hg-non-existent
tried to fall back to a 'hg-non-existent' sub-process but got error $ENOENT$
unsupported feature: error: Found argument '--exclude' which wasn't expected, or isn't valid in this context
USAGE:
rhg cat [OPTIONS] <FILE>...
For more information try --help
[252]
$ rhg cat original --exclude="*.rs" --config rhg.fallback-executable=rhg
Blocking recursive fallback. The 'rhg.fallback-executable = rhg' config points to `rhg` itself.
unsupported feature: error: Found argument '--exclude' which wasn't expected, or isn't valid in this context
USAGE:
rhg cat [OPTIONS] <FILE>...
For more information try --help
[252]
Fallback with shell path segments
$ $NO_FALLBACK rhg cat .
unsupported feature: `..` or `.` path segment
[252]
$ $NO_FALLBACK rhg cat ..
unsupported feature: `..` or `.` path segment
[252]
$ $NO_FALLBACK rhg cat ../..
unsupported feature: `..` or `.` path segment
[252]
Fallback with filesets
$ $NO_FALLBACK rhg cat "set:c or b"
unsupported feature: fileset
[252]
Fallback with generic hooks
$ $NO_FALLBACK rhg cat original --config hooks.pre-cat=something
unsupported feature: pre-cat hook defined
[252]
$ $NO_FALLBACK rhg cat original --config hooks.post-cat=something
unsupported feature: post-cat hook defined
[252]
$ $NO_FALLBACK rhg cat original --config hooks.fail-cat=something
unsupported feature: fail-cat hook defined
[252]
Fallback with [defaults]
$ $NO_FALLBACK rhg cat original --config "defaults.cat=-r null"
unsupported feature: `defaults` config set
[252]
Requirements
$ $NO_FALLBACK rhg debugrequirements
dotencode
fncache
generaldelta
persistent-nodemap
revlog-compression-zstd (zstd !)
revlogv1
share-safe
sparserevlog
store
$ echo indoor-pool >> .hg/requires
$ $NO_FALLBACK rhg files
unsupported feature: repository requires feature unknown to this Mercurial: indoor-pool
[252]
$ $NO_FALLBACK rhg cat -r 1 copy_of_original
unsupported feature: repository requires feature unknown to this Mercurial: indoor-pool
[252]
$ $NO_FALLBACK rhg debugrequirements
unsupported feature: repository requires feature unknown to this Mercurial: indoor-pool
[252]
$ echo -e '\xFF' >> .hg/requires
$ $NO_FALLBACK rhg debugrequirements
abort: parse error in 'requires' file
[255]
Persistent nodemap
$ cd $TESTTMP
$ rm -rf repository
$ hg --config format.use-persistent-nodemap=no init repository
$ cd repository
$ $NO_FALLBACK rhg debugrequirements | grep nodemap
[1]
$ hg debugbuilddag .+5000 --overwritten-file --config "storage.revlog.nodemap.mode=warn"
$ hg id -r tip
c3ae8dec9fad tip
$ ls .hg/store/00changelog*
.hg/store/00changelog.d
.hg/store/00changelog.i
$ $NO_FALLBACK rhg files -r c3ae8dec9fad
of
$ cd $TESTTMP
$ rm -rf repository
$ hg --config format.use-persistent-nodemap=True init repository
$ cd repository
$ $NO_FALLBACK rhg debugrequirements | grep nodemap
persistent-nodemap
$ hg debugbuilddag .+5000 --overwritten-file --config "storage.revlog.nodemap.mode=warn"
$ hg id -r tip
c3ae8dec9fad tip
$ ls .hg/store/00changelog*
.hg/store/00changelog-*.nd (glob)
.hg/store/00changelog.d
.hg/store/00changelog.i
.hg/store/00changelog.n
Specifying revisions by changeset ID
$ $NO_FALLBACK rhg files -r c3ae8dec9fad
of
$ $NO_FALLBACK rhg cat -r c3ae8dec9fad of
r5000
Crate a shared repository
$ echo "[extensions]" >> $HGRCPATH
$ echo "share = " >> $HGRCPATH
$ cd $TESTTMP
$ hg init repo1
$ echo a > repo1/a
$ hg -R repo1 commit -A -m'init'
adding a
$ hg share repo1 repo2
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
And check that basic rhg commands work with sharing
$ $NO_FALLBACK rhg files -R repo2
repo2/a
$ $NO_FALLBACK rhg -R repo2 cat -r 0 repo2/a
a
Same with relative sharing
$ hg share repo2 repo3 --relative
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ $NO_FALLBACK rhg files -R repo3
repo3/a
$ $NO_FALLBACK rhg -R repo3 cat -r 0 repo3/a
a
Same with share-safe
$ echo "[format]" >> $HGRCPATH
$ echo "use-share-safe = True" >> $HGRCPATH
$ cd $TESTTMP
$ hg init repo4
$ cd repo4
$ echo a > a
$ hg commit -A -m'init'
adding a
$ cd ..
$ hg share repo4 repo5
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
And check that basic rhg commands work with sharing
$ cd repo5
$ $NO_FALLBACK rhg files
a
$ $NO_FALLBACK rhg cat -r 0 a
a
The blackbox extension is supported
$ echo "[extensions]" >> $HGRCPATH
$ echo "blackbox =" >> $HGRCPATH
$ echo "[blackbox]" >> $HGRCPATH
$ echo "maxsize = 1" >> $HGRCPATH
$ $NO_FALLBACK rhg files > /dev/null
$ cat .hg/blackbox.log
????-??-?? ??:??:??.??? * @d3873e73d99ef67873dac33fbcc66268d5d2b6f4 (*)> (rust) files exited 0 after 0.??? seconds (glob)
$ cat .hg/blackbox.log.1
????-??-?? ??:??:??.??? * @d3873e73d99ef67873dac33fbcc66268d5d2b6f4 (*)> (rust) files (glob)
Subrepos are not supported
$ touch .hgsub
$ $NO_FALLBACK rhg files
unsupported feature: subrepos (.hgsub is present)
[252]
$ rhg files
a
$ rm .hgsub
The `:required` extension suboptions are correctly ignored
$ echo "[extensions]" >> $HGRCPATH
$ echo "blackbox:required = yes" >> $HGRCPATH
$ rhg files
a
$ echo "*:required = yes" >> $HGRCPATH
$ rhg files
a
We can ignore all extensions at once
$ echo "[extensions]" >> $HGRCPATH
$ echo "thisextensionbetternotexist=" >> $HGRCPATH
$ echo "thisextensionbetternotexisteither=" >> $HGRCPATH
$ $NO_FALLBACK rhg files
unsupported feature: extensions: thisextensionbetternotexist, thisextensionbetternotexisteither (consider adding them to 'rhg.ignored-extensions' config)
[252]
$ echo "[rhg]" >> $HGRCPATH
$ echo "ignored-extensions=*" >> $HGRCPATH
$ $NO_FALLBACK rhg files
a