Labs/Bespin/DeveloperGuide/UsingMercurial

Here are some tips about using Mercurial, based on our experiences managing the Bespin project with it.

Getting Started

Our main code repository is hosted at http://hg.mozilla.org/labs/bespinclient. You can pull from that by:

• Downloading Mercurial
• Configuring your environment. For example you will at least want to setup a username. I use:

[ui]
username = Dion Almaer <dion@mozilla.com>

[extensions]
rebase =
hgext.extdiff =

[extdiff]
cmd.opendiff = opendiff-w

[merge-tools]
filemerge.executable = opendiff-w
filemerge.args = $local $other -ancestor $base -merge $output

• Setup a bitbucket.org account that you can use as your repository
  • clone Bespin from our repo to yours and then checkout THAT repo locally to work on

• Read up:
  • Mozilla on Mercurial
  • Mercurial Definitive Guide

Best Practices

• Use "hg pull --rebase"
  • You need the "rebase =" line in your config
  • It will automatically handle merging, so instead of manually doing hg pull / hg merge, just do hg pull --rebase and let it do its job. By rebasing, we don't end up with lots of merge commits in the history.

• Look ahead
  • You can fetch away at will, but you can also run "hg incoming http://..." to see what would get pulled in. I have sometimes done this to release that there are a bunch of branches in there, and then I change my pull to only pull the tip default branch

• Eek, broken! How do I get back!
  • If you do a fetch/pull and something messes up (or any operation) you can do a "hg rollback" to revert back

• When checking in, use the bug number at the beginning of the message and then the web view will auto link to the bug.
  • E.g. hg ci -m "487459: Fixes the selection bug in Safari with -webkit-user-select: none;"

Contributing Back

When you are ready to send code back to the main repository, please take a look at Contributing to Bespin.