This is your friendly guide to contributing to Notmuch. In a nutshell, the Notmuch project maintains fairly high standards for code, review, tests, and documentation. It may seem a bit intimidating at first, and you may find it difficult to get your first contributions accepted, but once you get the hang of it, it'll be fun. This page should help you get there. DON'T PANIC.
The headlines below act as a checklist. Not all of them apply in all situations. Use your best judgment, and the Notmuch community will help out as needed.
- Contributing to Notmuch
- Obtain the Notmuch source code
- Make your changes
- Pay attention to the Notmuch coding style
- Split your commits in logical chunks
- Write meaningful commit messages
- Update the test suite
- Update the documentation
- Update NEWS
- Update command-line completion
- Subscribe to the Notmuch mailing list
- Send your patches to the mailing list
- Write a cover letter
- Tag your patches in nmbug
- Address review comments, participate in discussion
- Send another round addressing review comments
- Review other people's work
- Report bugs
- Update the Notmuch website
- Join the Notmuch IRC channel
The Notmuch source code is maintained in git. Get the source code using:
git clone git://notmuchmail.org/git/notmuch
This guide assumes a working knowledge of git. There are plenty of resources available on git, such as Pro Git and the git man pages. Please refer to them as necessary.
The changes you submit should almost always be based on the current Notmuch git master. There are plenty of ways to work in git, and this is not your git guide, but a typical workflow might start with:
git fetch origin git checkout -b my-local-branch origin/master # make changes git add ... git commit
If you're planning big changes, it may be advisable to not polish the patch series according to all the details described below at first. Instead, it may save everyone's time to introduce the idea using draft or work-in-progress patches, and get the design right from the beginning. Add a cover letter explaining what you want to achieve. You may prefix the subjects of such patches with "RFC" or "DRAFT" if you like.
The Notmuch code base follows a fairly uniform coding style. See the existing
code around your changes, and read
in the Notmuch source. It's not difficult to get it right, and may save you an
extra review round.
Each commit should contain one logical change only. The code should
build and the tests should pass after each commit. Changes to lib,
cli, emacs, tests, man pages, or news are usually best kept
separate. Also separate cleanups from functional changes. See the
Notmuch source history (
git log) for examples.
For in-depth discussion on the subject, see Software Release Practice HOWTO by Eric S. Raymond.
Quoting Carl, "The single line summary is good about saying what the commit does, but I always want to see at least one sentence about the why as well."
See also Pro Git on commit guidelines, including commit messages.
It is customary to prefix the subject line with "lib:", "cli:", "emacs:",
etc. depending on which part of Notmuch the commit is changing. See
Wrap the lines to about 72 characters.
If you want to share notes that shall not become part of the commit message when applied to the upstream Notmuch repository, add the notes at the end, after a line containing "---".
Notmuch has a test suite with fairly good coverage. At the very least,
test must pass after your changes. Therefore you must amend the tests if you
make functional changes that have existing test coverage. Preferably, you
should add new tests for any new functionality, and it helps in getting your
If you're fixing a bug, it is recommended to add a "known broken" test highlighting the issue in a first patch, and then fix the bug (and remove the known broken mark on the test) in the next patch in the series. This makes it easy to confirm your changes actually fix the issue. Some people use this approach also for adding new features.
in the Notmuch source for further information.
If you modify or add new features to the Notmuch command-line tools,
you should update the manual pages under the
doc directory of the
If you modify or add new features to the Notmuch Emacs UI, you should update the Emacs documentation.
If you make user visible changes, you should add an entry to the
If you modify or add new features to the Notmuch command-line tools, it
would be a nice bonus if you also updated the Notmuch command-line
completion scripts under the
completion directory of the Notmuch
source. Not required, but nice to have, and definitely can be done
While strictly not required, it is advisable to subscribe to the Notmuch mailing list before submitting patches.
Changes to Notmuch are contributed as emailed
Once you have your changes ready in your local repository, you need to
send them to the Notmuch mailing list. The simplest way is to use
send-email to send the patches directly from your repository:
git send-email --to email@example.com origin/master
An alternative is to do this in two steps; first generating patch
git format-patch), and then sending the patch files to
the mailing list (using
git send-email or a mail client):
git format-patch origin/master git send-email --to firstname.lastname@example.org *.patch
Either way, using
git send-email to actually send the patches is
recommended. It may be distributed separately from git, typically in a
If you are submitting a non-trivial set of patches, or if there's any
extra information you want to share that is not really part of the
commit messages, it is advisable to write a cover letter to give an
overview of your work. See the
Notmuch mailing list archives
for examples. Use the
--cover-letter option of
--compose option of
When you're developing an email tool, all the problems start looking like email. This applies to patch and bug tracking as well. The Notmuch project uses nmbug for tracking. The Notmuch developers will tag your patches too, making them show up in the nmbug status page, but requesting access and tagging your patches yourself will be helpful in the long run.
Each change to Notmuch must be peer reviewed before it is accepted, usually by one or two developers, depending on the impact of the changes. You are expected to follow up on the review comments you receive, either by discussing the comments and the code, or modifying your patches. Again, see the Notmuch mailing list archives for examples.
If your patches need to be changed based on review (they usually do),
you need to make the changes and re-submit.
git rebase -i is your
friend in updating your series. Also note that the upstream master may
have changed; be sure to rebase your updated changes on top of the
Once you have the updated series ready, send it to the mailing list
again. It will be helpful for others to use the
-vN option of
git send-email to add a version number of the patch
series to the subject (replacing vN with v2, v3, etc.) Use a cover
letter (or, in the case of a single patch, the notes after a "---" at
the end of the commit message) to summarize the main changes since the
previous version of the patch series. Also include the message-id
reference of the previous version.
--in-reply-to option of
git format-patch or
git send-email to send the patch series as a reply to the earlier
version is generally discouraged, particularly for large series, but
there are no hard rules. Usually the message-id reference to the
previous version is sufficient and preferred.
Tag the old patches obsolete in nmbug if you have access.
You scratch my back and I'll scratch yours. It will be easier to get people to review your patches if you review theirs.
Send bug reports to the Notmuch mailing list. Preferably prefix the subject line with "BUG:" or similar. Tag the message as a bug in nmbug.
Even better, send a patch adding a "known broken" test to the test suite highlighting the issue.
Update the Notmuch website, especially if you've landed a commit that changes or obsoletes information on the site. It's a wiki; see the instructions on how to edit the wiki.
Patch review happens on the Notmuch mailing list, but there is plenty of discussion going on in the freenode #notmuch IRC channel. See freenode.net/irc_servers.shtml for information how to get there.