Find a bug? Interested in contributing a bug fix or enhancement? Read on!

Filing Bugs

Bugs against software in this repository can be filed in the Developer Services Bugzilla product. The component should be obvious. If you are unsure, use General.

Contacting Us

The people that maintain the code in this repository lurk in the following IRC channels on

Where everybody who maintains all the version control properties hangs out.
Where developers and users of MozReview lurk.

Just pop in a channel, ask a question, and wait for someone to answer. The channels can be quiet for hours at a time, so please stick around if nobody replies at first.

Submitting Patches for Review

We use MozReview for conducting code review. Follow the MozReview User Guide to configure your Mercurial client. Then, hg push ssh:// to initiate the code review process.

Before submitting patches for review, please run the tests and verify things still work. Please also read the following section on how to optimally create commits.

Commit Creation Guidelines

We prefer many, smaller and focused commits than fewer, larger commits. Please read Phabricator’s Recommendations on Revision Control and apply the One Idea Per Commit practice to patches to this repository. Please also read their article on Writing Reviewable Code and tailor your commits appropriately.

It is recommended for commits to this repository to have the following commit message convention:

component: short description (bug xyz); r=reviewer

A sentence explaining the purpose of the patch. Another sentence
adding yet more detail.

Another paragraph adding yet more detail. We really like context to
exist in our patches rather than elsewhere.

The first line of the commit message begins with the component the patch is touching. Run hg log and see what others have used if you don’t know what to put here. The short description should be pretty obvious.

If the patch is tracked in a bug, please enclose the bug in parenthesis at the end of the commit message. This is different from the Firefox convention. We do things differently because we want the beginning of the commit message to emphasize the thing that was changed. This improves discovery when filtering through commit messages, as it allows you to easily and cheaply find all commits that changed a specific component. Furthermore, we prefer to work with the mentality of code, not bugs, being first. We defer the bug to the end of the summary line to reflect that.

Bug and Review Requirements

We do not require that every commit have a bug association. If there isn’t a bug on file, please don’t waste time filing one just to write a patch.

We do not require that every commit be reviewed.

Please abide by the following rules before pushing without a bug or review:

  • A review is required if you are modifying code that runs on a production service or we install or recommend installing on a user’s machine (MozReview, Mercurial extensions, Mercurial hooks, etc).
  • If you are adding new test code and you know what you are doing, you may not need a review. This exception is a little fuzzy around tests for production code (reviews are helpful to ensure the tests are accurate and proper).
  • If you are adding or hacking on a miscellaneous tool that doesn’t have test coverage or isn’t widely used or relied upon, you may not need a review.
  • You do not need a review to update documentation. If something is wrong, just fix it.
  • When in doubt, ask someone on #vcs if you need a review before pushing.

Pushing Commits

When pushing commits to ssh://, it is important for you to set the @ bookmark to the new tip.

Say you’ve created a new head or bookmark for your commit series. Assuming the working directory of your repository is on the commit you wish to make the new repository tip, here is how you should land your changes:

$ hg pull
pulling from default
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
updating bookmark @

$ hg rebase -d @
$ hg bookmark @
moving bookmark '@' forward from abcdef012345

$ hg push -B @
pushing to default
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 4 files
exporting bookmark @

If you fail to update the remote @ bookmark, nothing bad should happen. So don’t worry too much if you forget to do it from time to time.

If you do forget, just perform a hg push -B @ any time to update the remote bookmark. You can do this if you have no new changesets to push.