Mercurial > hg
view tests/test-diffstat.t @ 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 | 786289423e97 |
children | 3e3f4c03876b |
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$ hg init repo $ cd repo $ i=0; while [ "$i" -lt 213 ]; do echo a >> a; i=`expr $i + 1`; done $ hg add a $ cp a b $ hg add b Wide diffstat: $ hg diff --stat a | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ b | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 426 insertions(+), 0 deletions(-) diffstat width: $ COLUMNS=24 hg diff --config ui.interactive=true --stat a | 213 ++++++++++++++ b | 213 ++++++++++++++ 2 files changed, 426 insertions(+), 0 deletions(-) $ hg ci -m adda $ cat >> a <<EOF > a > a > a > EOF Narrow diffstat: $ hg diff --stat a | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) $ hg ci -m appenda >>> open("c", "wb").write("\0") $ touch d $ hg add c d Binary diffstat: $ hg diff --stat c | Bin 1 files changed, 0 insertions(+), 0 deletions(-) Binary git diffstat: $ hg diff --stat --git c | Bin d | 0 2 files changed, 0 insertions(+), 0 deletions(-) $ hg ci -m createb >>> open("file with spaces", "wb").write("\0") $ hg add "file with spaces" Filename with spaces diffstat: $ hg diff --stat file with spaces | Bin 1 files changed, 0 insertions(+), 0 deletions(-) Filename with spaces git diffstat: $ hg diff --stat --git file with spaces | Bin 1 files changed, 0 insertions(+), 0 deletions(-) Filename without "a/" or "b/" (issue5759): $ hg diff --config 'diff.noprefix=1' -c1 --stat --git a | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) $ hg diff --config 'diff.noprefix=1' -c2 --stat --git c | Bin d | 0 2 files changed, 0 insertions(+), 0 deletions(-) $ hg log --config 'diff.noprefix=1' -r '1:' -p --stat --git changeset: 1:3a95b07bb77f user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: appenda a | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a a --- a +++ a @@ -211,3 +211,6 @@ a a a +a +a +a changeset: 2:c60a6c753773 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: createb c | Bin d | 0 2 files changed, 0 insertions(+), 0 deletions(-) diff --git c c new file mode 100644 index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..f76dd238ade08917e6712764a16a22005a50573d GIT binary patch literal 1 Ic${MZ000310RR91 diff --git d d new file mode 100644 diffstat within directories: $ hg rm -f 'file with spaces' $ mkdir dir1 dir2 $ echo new1 > dir1/new $ echo new2 > dir2/new $ hg add dir1/new dir2/new $ hg diff --stat dir1/new | 1 + dir2/new | 1 + 2 files changed, 2 insertions(+), 0 deletions(-) $ hg diff --stat --root dir1 new | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) $ hg diff --stat --root dir1 dir2 warning: dir2 not inside relative root dir1 $ hg diff --stat --root dir1 -I dir1/old $ cd dir1 $ hg diff --stat . dir1/new | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) $ hg diff --stat --root . new | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) $ hg diff --stat --root ../dir1 ../dir2 warning: ../dir2 not inside relative root . $ hg diff --stat --root . -I old $ cd .. Files with lines beginning with '--' or '++' should be properly counted in diffstat $ hg up -Cr tip 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ rm dir1/new $ rm dir2/new $ rm "file with spaces" $ cat > file << EOF > line 1 > line 2 > line 3 > EOF $ hg commit -Am file adding file Lines added starting with '--' should count as additions $ cat > file << EOF > line 1 > -- line 2, with dashes > line 3 > EOF $ hg diff --root . diff -r be1569354b24 file --- a/file Thu Jan 01 00:00:00 1970 +0000 +++ b/file * (glob) @@ -1,3 +1,3 @@ line 1 -line 2 +-- line 2, with dashes line 3 $ hg diff --root . --stat file | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) Lines changed starting with '--' should count as deletions $ hg commit -m filev2 $ cat > file << EOF > line 1 > -- line 2, with dashes, changed again > line 3 > EOF $ hg diff --root . diff -r 160f7c034df6 file --- a/file Thu Jan 01 00:00:00 1970 +0000 +++ b/file * (glob) @@ -1,3 +1,3 @@ line 1 --- line 2, with dashes +-- line 2, with dashes, changed again line 3 $ hg diff --root . --stat file | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) Lines changed starting with '--' should count as deletions and starting with '++' should count as additions $ cat > file << EOF > line 1 > ++ line 2, switched dashes to plusses > line 3 > EOF $ hg diff --root . diff -r 160f7c034df6 file --- a/file Thu Jan 01 00:00:00 1970 +0000 +++ b/file * (glob) @@ -1,3 +1,3 @@ line 1 --- line 2, with dashes +++ line 2, switched dashes to plusses line 3 $ hg diff --root . --stat file | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)