Launchpad Help > Code > Code review

Overview

Thanks to Bazaar's distributed model, you can get full access to the code of any branch hosted in Launchpad, with version control and history, right on your own machine.

That flexibility means you can start work on a project without having to get special permissions to commit code. Of course, if you make changes that you want to see integrated into the project's main line you need a way of telling the main line's owner that you want to merge.

Launchpad and Bazaar make that easy. Bazaar was made to merge: even complex merges can be relatively easy. Launchpad helps look after the community process of discussing whether a proposed merge is a good idea.

Proposing a merge

When you've come to a stage in your development where you're ready to merge your code into another branch registered against the project - such as its main line - you can make a public merge proposal.

To do so, visit your branch's overview page, click Propose for merging into another branch, then follow the on-screen instructions.

Now, Launchpad will notify the proposed target branch's owner of your proposal. Anyone viewing the overview page for your branch, or the target branch, will also see a link to view the details of your proposal.

Code review

Once you've proposed a merge, anyone who has a Launchpad account can comment and vote on the proposal. Taking part in a code review is virtually hassle-free:

• no barriers: anyone can take part, so long as they have a Launchpad account

• convenient: you can get updates and contribute using email, as well as the web interface.

Each review consists of votes - approve, abstain or disapprove - and a threaded conversation much as you might find on a web forum or a mailing list. If you're already familiar with Launchpad Bugs, you'll be right at home with code reviews.

As a subscriber to the branch or a participant in the code review, you'll receive email updates each time someone adds a vote or message to the review. Just as with the bug tracker, you can take part in the review both by visiting Launchpad's web interface and by replying to any of the emails you receive. In effect, each code review becomes an ad-hoc mailing list that exists for the lifetime of the review.

If you want to make your vote specific to one aspect of the proposed merge, you can add a tag. For example: if you wanted to vote disapprove, based on the user interface, you could add a tag of ui.

For an example of a review, take a look at a code review in the Storm project.

Email interface

Using the code review email interface is straightforward. Reply to an email from the code review and your comment is added to the discussion in Launchpad. Here is the list of available commands:

Note that you must start the command line with a space or your command will not be recognized.

• review - inform the developer what you think of their changes

  • review approve - approve the change (alias: +1)

  • review disapprove - disapprove of the change (alias: -1)

  • review abstain - abstain from deciding (alias: -0 and +0)

  • review resubmit - tell the developer to rework the change

  • review needs_fixing - tell the developer that a few things need improvement (alias: needsfixing and needs-fixing)

• status - set the status on the entire merge proposal

  • status approve - approve of the merge proposal (alias: approved)

  • status reject - reject the merge proposal (alias: rejected)

• reviewer - add a new reviewer to the merge proposal

  • reviewer <name> where <name> is the Launchpad user name or email address of the new reviewer.

• vote (deprecated: use review)

You can combine commands, so if you wanted to vote disapprove, add a tag of UI, leave a comment, and reject the merge proposal, you'd write:

This is a sensible change but I find the user interface confusing.

 review disapprove UI
 status reject

Next step

You can pick choose which parts of Launchpad you want to use. However, when you use different parts of Launchpad together you can make them work together. Let's look at how you can link bug report and blueprints to branches of code.