Oxidized Mercurial

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

Under the hood, the project uses
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 Matt 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