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Using Bazaar

RJ Skerry-Ryan edited this page Sep 13, 2012 · 27 revisions

Using Bazaar

Official documentation

GUI clients

Here's a list of graphical Bazaar clients that Mixxx developers have tested:


  • Bazaar w/ TortoiseBZR - Works well in check-out mode. Distributed online mode is slow in large directories. (Tested by Pegasus)

Mac OS X

  • Bazaar Explorer
    • Full featured desktop application providing an easy-to-use interface to the Bazaar version control system for MacOS 10.5+. (Tested by Jus)
  • Launch Bazaar Explorer after install from the terminal with bzr explorer


  • Olive (bzr-gtk) - Looks promising but is god-awful slow on large directories like our src/ (Tested by Pegasus)


  • QBzr - QBzr provides GUI frontend for many core bzr commands and several universal dialogs and helper commands. Equivalents for core bzr commands has the same names as CLI commands but with prefix "q" (qlog, qcommit etc). Tested on linux, seems convenient sometimes if you are used to command-line workflow.

List of available branches

General procedure for distributed use

  1. Create a personal copy (called a "branch") of the Mixxx trunk/branch you want to work on using bzr branch lp:mixxx for trunk or bzr branch lp:mixxx/1.x for the 1.x release branch (replace 'x' with the latest release branch -- as of Sep 2012 this is 1.11). This copies the code to your local system. (Be patient as the Mixxx code base is fairly large and older versions of bzr sometimes have difficulty reporting progress.)
  2. Make changes to the code as desired. Every so often issue bzr commit -m 'log message' which will "commit" the changes to your local store, allowing you to review or revert later.
  3. To periodically update from the parent, issue bzr pull. If that gives you errors, (and it likely will if changes have been made to both) use bzr merge instead, since you're technically "merging" the parent repository with your local one.
  4. Register a new personal branch with Launchpad if you haven't already: You can create as many as you want, such as when working on different features. To create new branches on launchpad you can just `bzr push lp:~$USER/mixxx/$NEW_BRANCH_NAME`.
  5. When you're ready to share with others, or if you're doing lots of local commits and want to prevent losing data, issue bzr push lp:~<your-lp-name>/mixxx/<your-branch-name> which actually copies your local store to your personal LP-hosted branch.
  6. When your branch is stable and ready for inclusion into trunk or the corporate branch, go to your branch's web page and click "Propose for merging into another branch" and fill in the form. You'll want to specify "mixxxdevelopers" as the reviewer. When you click the "Propose Merge" button, the Mixxx developers will be notified and will review & test your branch when they have a chance. They will then either merge it with the corporate code base or make notations on the proposal page with questions or suggested changes.

General Procedure for Distributed Use With Push Access

If you have push/commit permissions on Launchpad and you are using distributed mode (i.e. branches), do not push from your local branch. Because of the way that Launchpad represents branch history, this will cause the history view to bunch commits by others into single commits by you from when you merge changes from upstream. The proper way to work in this mode is to maintain two branches, a features branch, and a clean branch. The following example will use the Mixxx 1.8 release branch as an example.

  1. Create a clean branch: bzr branch lp:mixxx/1.8 ./mixxx-1.8
  2. Create a features branch: bzr branch ./mixxx-1.8 ./mixxx-1.8-features
  3. Add features/code to your features branch: hack away at your features branch, and commit whenever you want at whatever interval you want. Ideally you will commit often with brief messages about what the commit did. These commit messages will not be displayed to everyone once you push the changes back to Mixxx. They will only show up if somebody decides they want to see the details of the commits you made for your feature branch.
  4. When you are ready to push the changes upstream: from your clean branch (the mixxx-1.8 folder): bzr pull, bzr merge ../mixxx-1.8-features. Now your branch is merged with the latest upstream changes, but it isn't committed yet. Resolve conflicts, compile Mixxx, run the test suite, and make sure that the feature and the upstream changes work well together.
  5. Commit the merge of your feature branch: bzr commit --fixes lp:XXXXXX. The commit message you enter here will be what the rest of the developers see. They will only see this message, the commit messages you made in your features branch will not be immediately available unless they drill-down into the merge on the history view. If you provide a --fixes argument to commit, then this will attach the launchpad bug #XXXXXX to the branch you commit to (mixxx-1.8 in this case).
  6. Push the merged feature branch upstream: bzr push

Your clean branch will represent the clean state of the remote Mixxx codebase once you bzr pull, but your features branch will never update unless you do it manually. To bring your features branch up to date:

  1. Make sure your features branch does not have uncommitted changes!: This is very important, or you will end up committing your changes when you commit the merge, and you usually do not want to do this. You can easily temporarily put changes away by using bzr shelve, if you do not have it then you need to install bzrtools. bzr shelve is similar to git stash.
  2. Update your clean branch: From your clean branch (the mixxx-1.8 folder): bzr pull
  3. Merge the upstream changes from your clean branch to your features branch: From your features branch (the mixxx-1.8-features folder): bzr merge ../mixxx-1.8
  4. Commit the merge: Resolve any conflicts, and when you are done bzr commit. You usually will provide a commit message with something along the lines of Merging changes from upstream. This commit message will not show up when you push your changes to Launchpad using the guide above, since bzr will realize that the merge was applying patches that were already applied to the remote branch.

Making it work like SVN (a.k.a. Centralized Mode)

(For those of us scared of this "distributed" thing...)

  • Check out with bzr checkout lp:mixxx for trunk or bzr checkout lp:mixxx/1.x for the 1.x release branch (replace 'x' with the latest release branch – as of Sep 2012 this is 1.11). (Be patient as the Mixxx code base is fairly large and older versions of bzr sometimes have difficulty reporting progress.)
  • Update to latest version with bzr update
  • Create a patch with bzr diff > mychanges.patch and attach it to a bug at Launchpad.
  • If you have commit access, commit with bzr commit -m "Log message" (You'll need to register an SSH key first under your personal LP page:

Automatic submission to CIA

Mixxx has a CIA bot in our freenode channel that will dutifully announce any commits to the codebase. To make this work for you, do the following:

  1. Set up an account at
  2. Install your distribution's cia-clients package, or manually install the plugin from the Launchpad project page
  3. At a command prompt in at the root directory of the branch/checkout you're working on, enter bzr cia-project Mixxx
  4. In ~/.bazaar/bazaar.conf, set 'cia_user' to your username on the system

That's it. The next time you push/commit code from this branch/checkout, CIA will be notified.


Pull or Checkout

If when trying to pull/checkout a shared branch, you get an error like bzr: ERROR: Connection closed: Unexpected end of message. Please check connectivity and permissions, and report a bug if problems persist. then you need to either:

  • Edit ~/.bazzar/bazzar.conf and remove the launchpad_username line
  • Or register your SSH key with Launchpad. (See details below.)

Push or Commit

If when trying to push/commit to a shared branch, you get an error like bzr: ERROR: Cannot lock LockDir( Transport operation not possible: http does not support mkdir() then you need to do the folllowing:

  1. Register your SSH key with Launchpad as above and tell Bazaar about it. Instructions
  2. Issue the command bzr launchpad-login <your lp username>
  3. If it still doesn't work, issue the command bzr bind bzr+ssh://<your lp username><branch name>

Tips and Tricks

Note that I (bkgood, ping me if you have issues) have no idea if any of this works in "centralized" mode, I like branches =)

Save disk space and bandwidth

Each mixxx branch can take (and transfer) something like 80MB for history. As most of that is common throughout all your mixxx branches, bazaar can share the common history throughout your branches, with a shared repository. Follow the directions (see "Shared Repository Example") to learn more. For example, I have a repository at ~/src/mixxx and then have my branches (trunk, 1.9, ...) under that. There's a large (79MB) .bzr directory in the repository directory, and then each branch under it has a .bzr directory in the .5-2MB range, so the payoff is quite significant versus 79MB for each branch. Note that branch directories will still be huge when built because of the massive amount of space the object files take.

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