Quick Start

Build

Run the following::

~/fbsource/fbcode/eden/scm$ make local

The locally built hg will be available at ~/fbsource/fbcode/eden/scm/hg.

You may want to create a script like ~/bin/lhg on your $PATH (lhg == "local hg") to facilitate running the dev version::

#!/bin/bash CHGDISABLE=1 ~/fbsource/fbcode/eden/scm/hg "$@"

Test

To test native components: cd lib && cargo test.

To run integration tests (the main test suite): Build. Then run cd tests && ./run-tests.py.

Directory Layout

• mercurial: core Python modules and pure C utilities
  • mercurial/cext: C Python wrappers
  • mercurial/rust: Rust Python wrappers
• lib: Native components unrelated to Python
• exec: Native standalone executable projects unrelated to Python
• ext: Extensions
  • ext/extlib: Python wrappers. Similar to mercurial/rust or mercurial/cext, but for extensions.
• tests: Mostly integration tests

.. note:: The above layout assumes that hg is mainly a Python program. That will change over time.

Coding Style

tl;dr: Mimic the style of the existing code.

Python

Use ``foobar`` naming, not ``foo_bar``, nor ``fooBar``. Use ``_foobar`` for private fields.

Use full English words for variable names. Except for well-know ones:
  - ``p1``, ``p2``: first and second parents
  - ``ctx``, ``fctx``: ``context.changectx`` and ``context.filectx`` instances
  - ``fp``, ``fd``: python file-like object, file descriptor
  - ``repo``, ``unfi``: repo, unfiltered repo instances

Rust
~~~~

Use `foo_bar`, like the rest of the Rust community.

Use `def foobar` for Python bindings used in the ``foobar``-style code base.

Try match the Rust community standard. Especially for documentation.

Commit

Use [hg] topic: short summary without capital letters for commit title.

What's next

To add commands, revsets as an extension. See :doc:WritingExtensions.

To make the codebase more confident. See :doc:WritingTests.

To understand internal data structures and protocols. See (TODO).