rust/hgcli/README.md
author Pulkit Goyal <7895pulkit@gmail.com>
Sun, 11 Apr 2021 00:50:10 +0530
changeset 47404 ebdef6283798
parent 46819 d4ba4d51f85f
child 48268 16c3fe46929a
permissions -rw-r--r--
rhg: read [paths] for `--repository` value hg parses `-R` and `--repository` CLI arguments "early" in order to know which local repository to load config from. (Config can then affect whether or how to fall back.) The value of of those arguments can be not only a filesystem path, but also an alias configured in the `[paths]` section. This part was missing in rhg and this patch implements that. The current patch still lacks functionality to read config of current repository if we are not at root of repo. That will be fixed in upcoming patches. A new crate `home` is added to get path of home directory. Differential Revision: https://phab.mercurial-scm.org/D10296

# Oxidized Mercurial

This project provides a Rust implementation of the Mercurial (`hg`)
version control tool.

Under the hood, the project uses
[PyOxidizer](https://github.com/indygreg/PyOxidizer) to embed a Python
interpreter in a binary built with Rust. At run-time, the Rust `fn main()`
is called and Rust code handles initial process startup. An in-process
Python interpreter is started (if needed) to provide additional
functionality.

# Building

This project currently requires an unreleased version of PyOxidizer
(0.7.0-pre). For best results, build the exact PyOxidizer commit
as defined in the `pyoxidizer.bzl` file:

    $ git clone https://github.com/indygreg/PyOxidizer.git
    $ cd PyOxidizer
    $ git checkout <Git commit from pyoxidizer.bzl>
    $ cargo build --release

Then build this Rust project using the built `pyoxidizer` executable::

    $ /path/to/pyoxidizer/target/release/pyoxidizer build

If all goes according to plan, there should be an assembled application
under `build/<arch>/debug/app/` with an `hg` executable:

    $ build/x86_64-unknown-linux-gnu/debug/app/hg version
    Mercurial Distributed SCM (version 5.3.1+433-f99cd77d53dc+20200331)
    (see https://mercurial-scm.org for more information)

    Copyright (C) 2005-2020 Olivia Mackall and others
    This is free software; see the source for copying conditions. There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# Running Tests

To run tests with a built `hg` executable, you can use the `--with-hg`
argument to `run-tests.py`. But there's a wrinkle: many tests run custom
Python scripts that need to `import` modules provided by Mercurial. Since
these modules are embedded in the produced `hg` executable, a regular
Python interpreter can't access them! To work around this, set `PYTHONPATH`
to the Mercurial source directory. e.g.:

    $ cd /path/to/hg/src/tests
    $ PYTHONPATH=`pwd`/.. python3.7 run-tests.py \
        --with-hg `pwd`/../rust/hgcli/build/x86_64-unknown-linux-gnu/debug/app/hg