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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 You can pull from that by:

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

rebase =
hgext.extdiff =

cmd.opendiff = opendiff-w

filemerge.executable = opendiff-w
filemerge.args = $local $other -ancestor $base -merge $output
  • Setup a account that you can use as your repository
    • clone Bespin from our repo to yours and then checkout THAT repo locally to work on

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.