typing: add type hints to mercurial/help.py
Was hoping to find more issues like f09bc2ed9100, but it may be that nothing
checks the args to that operation. In any event, the work is done and pytype
doesn't do a very good job inferring the types. A few of th emore complicated
things like the command table are left untyped, because they come from modules
that aren't typed yet.
# 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
First, acquire and build a copy of PyOxidizer; you probably want to do this in
some directory outside of your clone of Mercurial:
$ git clone https://github.com/indygreg/PyOxidizer.git
$ cd PyOxidizer
$ cargo build --release
Then build this Rust project using the built `pyoxidizer` executable:
$ /path/to/pyoxidizer/target/release/pyoxidizer build --release
If all goes according to plan, there should be an assembled application
under `build/<arch>/release/app/` with an `hg` executable:
$ build/x86_64-unknown-linux-gnu/release/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`/.. python3.9 run-tests.py \
--with-hg `pwd`/../rust/hgcli/build/x86_64-unknown-linux-gnu/release/app/hg