Mercurial > hg
annotate hgeditor @ 35569:964212780daf
rust: implementation of `hg`
This commit provides a mostly-working implementation of the
`hg` script in Rust along with scaffolding to support Rust in
the repository.
If you are familiar with Rust, the contents of the added rust/
directory should be pretty straightforward. We create an "hgcli"
package that implements a binary application to run Mercurial.
The output of this package is an "hg" binary.
Our Rust `hg` (henceforth "rhg") essentially is a port of the existing
`hg` Python script. The main difference is the creation of the embedded
CPython interpreter is handled by the binary itself instead of relying
on the shebang. In that sense, rhg is more similar to the "exe wrapper"
we currently use on Windows. However, unlike the exe wrapper, rhg does
not call the `hg` Python script. Instead, it uses the CPython APIs to
import mercurial modules and call appropriate functions. The amount of
code here is surprisingly small.
It is my intent to replace the existing C-based exe wrapper with rhg.
Preferably in the next Mercurial release. This should be achievable -
at least for some Mercurial distributions. The future/timeline for
rhg on other platforms is less clear. We already ship a hg.exe on
Windows. So if we get the quirks with Rust worked out, shipping a
Rust-based hg.exe should hopefully not be too contentious.
Now onto the implementation.
We're using python27-sys and the cpython crates for talking to the
CPython API. We currently don't use too much functionality of the
cpython crate and could have probably cut it out. However, it does
provide a reasonable abstraction over unsafe {} CPython function
calls. While we still have our fair share of those, at least we're
not dealing with too much refcounting, error checking, etc. So I
think the use of the cpython crate is justified. Plus, there is
not-yet-implemented functionality that could benefit from cpython. I
see our use of this crate only increasing.
The cpython and python27-sys crates are not without their issues.
The cpython crate didn't seem to account for the embedding use case
in its design. Instead, it seems to assume that you are building
a Python extension. It is making some questionable decisions around
certain CPython APIs. For example, it insists that
PyEval_ThreadsInitialized() is called and that the Python code
likely isn't the main thread in the underlying application. It
is also missing some functionality that is important for embedded
use cases (such as exporting the path to the Python interpreter
from its build script). After spending several hours trying to
wrangle python27-sys and cpython, I gave up and forked the project
on GitHub. Our Cargo.toml tracks this fork. I'm optimistic that
the upstream project will accept our contributions and we can
eventually unfork.
There is a non-trivial amount of code in our custom Cargo build
script. Our build.rs (which is called as part of building the hgcli
crate):
* Validates that the Python interpreter that was detected by the
python27-sys crate provides a shared library (we only support
shared library linking at this time - although this restriction
could be loosened).
* Validates that the Python is built with UCS-4 support. This ensures
maximum Unicode compatibility.
* Exports variables to the crate build allowing the built crate to e.g.
find the path to the Python interpreter.
The produced rhg should be considered alpha quality. There are several
known deficiencies. Many of these are documented with inline TODOs.
Probably the biggest limitation of rhg is that it assumes it is
running from the ./rust/target/<target> directory of a source
distribution. So, rhg is currently not very practical for real-world
use. But, if you can `cargo build` it, running the binary *should*
yield a working Mercurial CLI.
In order to support using rhg with the test harness, we needed to hack
up run-tests.py so the path to Mercurial's Python files is set properly.
The change is extremely hacky and is only intended to be a stop-gap
until the test harness gains first-class support for installing rhg.
This will likely occur after we support running rhg outside the
source directory.
Despite its officially alpha quality, rhg copes extremely well with
the test harness (at least on Linux). Using
`run-tests.py --with-hg ../rust/target/debug/hg`, I only encounter
the following failures:
* test-run-tests.t -- Warnings emitted about using an unexpected
Mercurial library. This is due to the hacky nature of setting the
Python directory when run-tests.py detected rhg.
* test-devel-warnings.t -- Expected stack trace missing frame for `hg`
(This is expected since we no longer have an `hg` script!)
* test-convert.t -- Test running `$PYTHON "$BINDIR"/hg`, which obviously
assumes `hg` is a Python script.
* test-merge-tools.t -- Same assumption about `hg` being executable with
Python.
* test-http-bad-server.t -- Seeing exit code 255 instead of 1 around
line 358.
* test-blackbox.t -- Exit code 255 instead of 1.
* test-basic.t -- Exit code 255 instead of 1.
It certainly looks like we have a bug around exit code handling. I
don't think it is severe enough to hold up review and landing of this
initial implementation. Perfect is the enemy of good.
Differential Revision: https://phab.mercurial-scm.org/D1581
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 10 Jan 2018 08:53:22 -0800 |
parents | 1aee2ab0f902 |
children |
rev | line source |
---|---|
544
3d4d5f2aba9a
Remove bashisms and use /bin/sh instead of /bin/bash.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
484
diff
changeset
|
1 #!/bin/sh |
186 | 2 # |
1599
f93fde8f5027
remove the gpg stuff from hgeditor (superseded by the signing extension)
Benoit Boissinot <benoit.boissinot@ens-lyon.org>
parents:
1009
diff
changeset
|
3 # This is an example of using HGEDITOR to create of diff to review the |
26781
1aee2ab0f902
spelling: trivial spell checking
Mads Kiilerich <madski@unity3d.com>
parents:
11266
diff
changeset
|
4 # changes while committing. |
684
4ccf3de52989
Turn off signing with hgeditor by default
Matt Mackall <mpm@selenic.com>
parents:
683
diff
changeset
|
5 |
666
0100a43788ca
hgeditor: Remove EMAIL default for HGUSER, comment editor selection
Radoslaw "AstralStorm" Szkodzinski <astralstorm@gorzow.mm.pl>
parents:
665
diff
changeset
|
6 # If you want to pass your favourite editor some other parameters |
0100a43788ca
hgeditor: Remove EMAIL default for HGUSER, comment editor selection
Radoslaw "AstralStorm" Szkodzinski <astralstorm@gorzow.mm.pl>
parents:
665
diff
changeset
|
7 # only for Mercurial, modify this: |
796
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
8 case "${EDITOR}" in |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
9 "") |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
10 EDITOR="vi" |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
11 ;; |
348
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
12 emacs) |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
13 EDITOR="$EDITOR -nw" |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
14 ;; |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
15 gvim|vim) |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
16 EDITOR="$EDITOR -f -o" |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
17 ;; |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
18 esac |
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
19 |
796
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
20 |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
21 HGTMP="" |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
22 cleanup_exit() { |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
23 rm -rf "$HGTMP" |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
24 } |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
25 |
754
3e73bf876f17
Fixes and cleanups to hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
684
diff
changeset
|
26 # Remove temporary files even if we get interrupted |
831
232d0616a80a
Cleaned up trap handling:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
814
diff
changeset
|
27 trap "cleanup_exit" 0 # normal exit |
11190
43337076ba92
Fixed a bashism with trap numbers in hgeditor.
Javi Merino <cibervicho@gmail.com>
parents:
4687
diff
changeset
|
28 trap "exit 255" HUP INT QUIT ABRT TERM |
796
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
29 |
11266
2b440bb8a66b
Fixed a bashism with the use of $RANDOM in hgeditor.
Javi Merino <cibervicho@gmail.com>
parents:
11190
diff
changeset
|
30 HGTMP=$(mktemp -d ${TMPDIR-/tmp}/hgeditor.XXXXXX) |
2b440bb8a66b
Fixed a bashism with the use of $RANDOM in hgeditor.
Javi Merino <cibervicho@gmail.com>
parents:
11190
diff
changeset
|
31 [ x$HGTMP != x -a -d $HGTMP ] || { |
2b440bb8a66b
Fixed a bashism with the use of $RANDOM in hgeditor.
Javi Merino <cibervicho@gmail.com>
parents:
11190
diff
changeset
|
32 echo "Could not create temporary directory! Exiting." 1>&2 |
2b440bb8a66b
Fixed a bashism with the use of $RANDOM in hgeditor.
Javi Merino <cibervicho@gmail.com>
parents:
11190
diff
changeset
|
33 exit 1 |
796
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
34 } |
33a272b79e54
Replaced mktemp and usage of ${par:=word}.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
769
diff
changeset
|
35 |
754
3e73bf876f17
Fixes and cleanups to hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
684
diff
changeset
|
36 ( |
3e73bf876f17
Fixes and cleanups to hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
684
diff
changeset
|
37 grep '^HG: changed' "$1" | cut -b 13- | while read changed; do |
4687
b5bbfa18daf7
hgeditor: Use $HG to run 'hg diff' (see 849f011dbf79)
Thomas Arendsen Hein <thomas@intevation.de>
parents:
4659
diff
changeset
|
38 "$HG" diff "$changed" >> "$HGTMP/diff" |
754
3e73bf876f17
Fixes and cleanups to hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
684
diff
changeset
|
39 done |
3e73bf876f17
Fixes and cleanups to hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
684
diff
changeset
|
40 ) |
348
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
41 |
1599
f93fde8f5027
remove the gpg stuff from hgeditor (superseded by the signing extension)
Benoit Boissinot <benoit.boissinot@ens-lyon.org>
parents:
1009
diff
changeset
|
42 cat "$1" > "$HGTMP/msg" |
684
4ccf3de52989
Turn off signing with hgeditor by default
Matt Mackall <mpm@selenic.com>
parents:
683
diff
changeset
|
43 |
3025
d9b8d28c0b94
Find the system's MD5 binary.
Will Maier <willmaier@ml1.net>
parents:
1706
diff
changeset
|
44 MD5=$(which md5sum 2>/dev/null) || \ |
4659
7a7d4937272b
Kill trailing spaces
Thomas Arendsen Hein <thomas@intevation.de>
parents:
3025
diff
changeset
|
45 MD5=$(which md5 2>/dev/null) |
3025
d9b8d28c0b94
Find the system's MD5 binary.
Will Maier <willmaier@ml1.net>
parents:
1706
diff
changeset
|
46 [ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"` |
1009
1bc619b12025
Don't show the diff in hgeditor if there are no changes in file contents.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
839
diff
changeset
|
47 if [ -s "$HGTMP/diff" ]; then |
1bc619b12025
Don't show the diff in hgeditor if there are no changes in file contents.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
839
diff
changeset
|
48 $EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $? |
1bc619b12025
Don't show the diff in hgeditor if there are no changes in file contents.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
839
diff
changeset
|
49 else |
1bc619b12025
Don't show the diff in hgeditor if there are no changes in file contents.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
839
diff
changeset
|
50 $EDITOR "$HGTMP/msg" || exit $? |
1bc619b12025
Don't show the diff in hgeditor if there are no changes in file contents.
Thomas Arendsen Hein <thomas@intevation.de>
parents:
839
diff
changeset
|
51 fi |
3025
d9b8d28c0b94
Find the system's MD5 binary.
Will Maier <willmaier@ml1.net>
parents:
1706
diff
changeset
|
52 [ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13) |
754
3e73bf876f17
Fixes and cleanups to hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
684
diff
changeset
|
53 |
1599
f93fde8f5027
remove the gpg stuff from hgeditor (superseded by the signing extension)
Benoit Boissinot <benoit.boissinot@ens-lyon.org>
parents:
1009
diff
changeset
|
54 mv "$HGTMP/msg" "$1" |
348
442eb02cf870
Improved hgeditor:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
280
diff
changeset
|
55 |
831
232d0616a80a
Cleaned up trap handling:
Thomas Arendsen Hein <thomas@intevation.de>
parents:
814
diff
changeset
|
56 exit $? |