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rhg: Add support for automatic fallback to Python...
rhg: Add support for automatic fallback to Python `rhg` is a command-line application that can do a small subset of what `hg` can. It is written entirely in Rust, which avoids the cost of starting a Python interpreter and importing many Python modules. In a script that runs many `hg` commands, this cost can add up. However making users decide when to use `rhg` instead of `hg` is not practical as we want the subset of supported functionality to grow over time. Instead we introduce "fallback" behavior where, when `rhg` encounters something (a sub-command, a repository format, …) that is not implemented in Rust-only, it does nothing but silently start a subprocess of Python-based `hg` running the same command. That way `rhg` becomes a drop-in replacement for `hg` that sometimes goes faster. Whether Python is used should be an implementation detail not apparent to users (other than through speed). A new `fallback` value is added to the previously introduced `rhg.on-unsupported` configuration key. When in this mode, the new `rhg.fallback-executable` config is determine what command to use to run a Python-based `hg`. The previous `rhg.on-unsupported = abort-silent` configuration was designed to let a wrapper script call `rhg` and then fall back to `hg` based on the exit code. This is still available, but having fallback behavior built-in in rhg might be easier for users instead of leaving that script "as an exercise for the reader". Using a subprocess like this is not idea, especially when `rhg` is to be installed in `$PATH` as `hg`, since the other `hg.py` executable needs to still be available… somewhere. Eventually this could be replaced by using PyOxidizer to a have a single executable that embeds a Python interpreter, but only starts it when needed. Differential Revision: https://phab.mercurial-scm.org/D10093

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test-rhg.t
309 lines | 7.3 KiB | text/troff | Tads3Lexer
#require rust
Define an rhg function that will only run if rhg exists
$ RHG="$RUNTESTDIR/../rust/target/release/rhg"
$ rhg() {
> if [ -f "$RHG" ]; then
> "$RHG" "$@"
> else
> echo "skipped: Cannot find rhg. Try to run cargo build in rust/rhg."
> exit 80
> fi
> }
Unimplemented command
$ 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
$ rhg root
abort: no repository found in '$TESTTMP' (.hg not found)!
[255]
$ hg init repository
$ cd repository
$ rhg root
$TESTTMP/repository
Reading and setting configuration
$ echo "[ui]" >> $HGRCPATH
$ echo "username = user1" >> $HGRCPATH
$ rhg config ui.username
user1
$ echo "[ui]" >> .hg/hgrc
$ echo "username = user2" >> .hg/hgrc
$ rhg config ui.username
user2
$ rhg --config ui.username=user3 config ui.username
user3
Unwritable file descriptor
$ rhg root > /dev/full
abort: No space left on device (os error 28)
[255]
Deleted repository
$ rm -rf `pwd`
$ rhg root
abort: $ENOENT$: current directory
[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
$ rhg files
file1
file2
file3
Listing tracked files from subdirectory
$ mkdir -p path/to/directory
$ cd path/to/directory
$ rhg files
../../../file1
../../../file2
../../../file3
Listing tracked files through broken pipe
$ 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
$ rhg debugdata -c 2
8d0267cb034247ebfa5ee58ce59e22e57a492297
test
0 0
file-3
Commit 3 (no-eol)
$ rhg debugdata -m 2
file-1\x00b8e02f6433738021a065f94175c7cd23db5f05be (esc)
file-2\x005d9299349fc01ddd25d0070d149b124d8f10411e (esc)
file-3\x002661d26c649684b482d10f91960cc3db683c38b4 (esc)
Debuging with full node id
$ 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
$ rhg files -r cf8b83
file-1
file-2
file-3
$ rhg cat -r cf8b83 file-2
2
$ rhg cat -r c file-2
abort: ambiguous revision identifier c
[255]
$ rhg cat -r d file-2
2
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
$ 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"
$ rhg cat -r 1 copy_of_original
original content
Fallback to Python
$ rhg cat original
unsupported feature: `rhg cat` without `--rev` / `-r`
[252]
$ FALLBACK="--config rhg.on-unsupported=fallback"
$ rhg cat original $FALLBACK
original content
$ rhg cat original $FALLBACK --config rhg.fallback-executable=false
[1]
$ rhg cat original $FALLBACK --config rhg.fallback-executable=hg-non-existent
tried to fall back to a 'hg-non-existent' sub-process but got error $ENOENT$
unsupported feature: `rhg cat` without `--rev` / `-r`
[252]
$ rhg cat original $FALLBACK --config rhg.fallback-executable="$RHG"
Blocking recursive fallback. The 'rhg.fallback-executable = */rust/target/release/rhg' config points to `rhg` itself. (glob)
unsupported feature: `rhg cat` without `--rev` / `-r`
[252]
Requirements
$ rhg debugrequirements
dotencode
fncache
generaldelta
revlogv1
sparserevlog
store
$ echo indoor-pool >> .hg/requires
$ rhg files
unsupported feature: repository requires feature unknown to this Mercurial: indoor-pool
[252]
$ rhg cat -r 1 copy_of_original
unsupported feature: repository requires feature unknown to this Mercurial: indoor-pool
[252]
$ rhg debugrequirements
unsupported feature: repository requires feature unknown to this Mercurial: indoor-pool
[252]
$ echo -e '\xFF' >> .hg/requires
$ rhg debugrequirements
abort: corrupted repository: parse error in 'requires' file
[255]
Persistent nodemap
$ cd $TESTTMP
$ rm -rf repository
$ hg init repository
$ cd repository
$ 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
$ rhg files -r c3ae8dec9fad
of
$ cd $TESTTMP
$ rm -rf repository
$ hg --config format.use-persistent-nodemap=True init repository
$ cd repository
$ 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
$ rhg files -r c3ae8dec9fad
of
$ 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
$ rhg files -R repo2
repo2/a
$ 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
$ rhg files -R repo3
repo3/a
$ 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
$ rhg files
a
$ rhg cat -r 0 a
a
The blackbox extension is supported
$ echo "[extensions]" >> $HGRCPATH
$ echo "blackbox =" >> $HGRCPATH
$ echo "[blackbox]" >> $HGRCPATH
$ echo "maxsize = 1" >> $HGRCPATH
$ 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)