hghave: list the module needed for the `vcr` check
I'm tired of having to look up modules each time I setup a system, and try to
distinguish between similar package names to get the right one. Now that the
search API has been disabled, it's even harder. There are other python packages
here that should be listed like this, but this is the one that came up missing
today, so it's a start.
Differential Revision: https://phab.mercurial-scm.org/D9879
# 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 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