1 [[!img notmuch-logo.png alt="Notmuch logo" class="left"]]
2 # Contributing to Notmuch
4 This is your friendly guide to contributing to Notmuch. In a nutshell,
5 the Notmuch project maintains fairly high standards for code, review,
6 tests, and documentation. It may seem a bit intimidating at first, and
7 you may find it difficult to get your first contributions accepted,
8 but once you get the hang of it, it'll be fun. This page should help
9 you get there. DON'T PANIC.
11 The headlines below act as a checklist. Not all of them apply in all
12 situations; use common sense.
16 ## Obtain the Notmuch source code
18 The Notmuch source code is maintained in [git](http://git-scm.com/). Get the
21 git clone git://notmuchmail.org/git/notmuch
23 This guide assumes a working knowledge of git. There are plenty of resources
24 available on git, such as [Pro Git](http://git-scm.com/book) and the git man
25 pages. Please refer to them as necessary.
29 The changes you submit should almost always be based on the current
30 Notmuch git master. There are plenty of ways to work in git, and this
31 is not your git guide, but a typical workflow might start with:
34 git checkout -b my-local-branch origin/master
39 If you're planning big changes, it may be advisable to __not__ polish
40 the patch series according to all the details described below at
41 first. Instead, it may save everyone's time to introduce the idea
42 using draft or work-in-progress patches, and get the design right from
43 the beginning. Add a cover letter explaining what you want to
44 achieve. You may prefix the subjects of such patches with "RFC" or
47 ## Pay attention to the Notmuch coding style
49 The Notmuch code base follows a fairly uniform coding style. See the existing
50 code around your changes, and read
51 [`devel/STYLE`](http://git.notmuchmail.org/git/notmuch/blob/HEAD:/devel/STYLE)
52 in the Notmuch source. It's not difficult to get it right, and may save you an
55 ## Split your commits in logical chunks
57 Each commit should contain one logical change only. The code should
58 build and the tests should pass after each commit. Changes to lib,
59 cli, emacs, tests, man pages, or news are usually best kept
60 separate. Also separate cleanups from functional changes. See the
61 Notmuch source history (`git log`) for examples.
63 For in-depth discussion on the subject, see
64 [Software Release Practice HOWTO](http://tldp.org/HOWTO/Software-Release-Practice-HOWTO/) by Eric S. Raymond.
66 ## Write meaningful commit messages
68 [Quoting Carl](http://article.gmane.org/gmane.mail.notmuch.general/504),
69 "The single line summary is good about saying what the commit does,
70 but I always want to see at least one sentence about the why as well."
73 [Pro Git](http://git-scm.com/book/en/Distributed-Git-Contributing-to-a-Project#Commit-Guidelines)
74 on commit guidelines, including commit messages.
76 It is customary to prefix the subject line with "lib:", "cli:", "emacs:",
77 etc. depending on which part of Notmuch the commit is changing. See `git log`
80 Wrap the lines to about 72 characters.
82 If you want to share notes that shall not become part of the commit
83 message when applied to the upstream Notmuch repository, add the notes
84 at the end, after a line containing "---".
86 ## Update the test suite
88 Notmuch has a test suite with fairly good coverage. At the very least, `make
89 test` must pass after your changes. Therefore you must amend the tests if you
90 make functional changes that have existing test coverage. Preferably, you
91 should add new tests for any new functionality, and it helps in getting your
94 If you're fixing a bug, it is recommended to add a "known broken" test
95 highlighting the issue in a first patch, and then fix the bug (and remove
96 the known broken mark on the test) in the next patch in the series. This
98 easy to confirm your changes actually fix the issue. Some people use this
99 approach also for adding new features.
102 [`test/README`](http://git.notmuchmail.org/git/notmuch/blob/HEAD:/test/README)
103 in the Notmuch source for further information.
105 ## Update the documentation
107 If you modify or add new features to the Notmuch command-line tools,
108 you should update the manual pages under the `man` directory of the
111 If you modify or add new features to the Notmuch Emacs UI, you should
112 update the Emacs documentation.
116 If you make user visible changes, you should add an entry to the
117 [`NEWS`](http://git.notmuchmail.org/git/notmuch/blob/HEAD:/NEWS) file.
119 ## Subscribe to the Notmuch mailing list
121 While strictly not required, it is advisable to subscribe to the
122 [Notmuch mailing list](http://notmuchmail.org/mailman/listinfo/notmuch)
123 before submitting patches.
125 ## Send your patches to the mailing list
127 Changes to Notmuch are contributed as [emailed
128 patches](http://git-scm.com/book/en/Distributed-Git-Contributing-to-a-Project#Public-Large-Project).
129 Once you have your changes ready in your local repository, you need to
130 send them to the Notmuch mailing list. The simplest way is to use `git
131 send-email` to send the patches directly from your repository:
133 git send-email --to notmuch@notmuchmail.org origin/master
135 An alternative is to do this in two steps; first generating patch
136 files (using `git format-patch`), and then sending the patch files to
137 the mailing list (using `git send-email` or a mail client):
139 git format-patch origin/master
140 git send-email --to notmuch@notmuchmail.org *.patch
142 Either way, using `git send-email` to actually send the patches is
143 recommended. It may be distributed separately from git, typically in a
144 package named `git-email`.
146 ## Write a cover letter
148 If you are submitting a non-trivial set of patches, or if there's any
149 extra information you want to share that is not really part of the
150 commit messages, it is advisable to write a cover letter to give an
151 overview of your work. See the
152 [Notmuch mailing list archives](http://notmuchmail.org/pipermail/notmuch/)
153 for examples. Use the `--cover-letter` option of `git format-patch`,
154 or `--compose` option of `git send-email`.
156 ## Tag your patches in nmbug
158 When you're developing an email tool, all the problems start looking
159 like email. This applies to patch and bug tracking as well. The
160 Notmuch project uses [nmbug](http://notmuchmail.org/nmbug/) for
161 tracking. The Notmuch developers will tag your patches too, making
163 [nmbug status page](http://nmbug.tethera.net/status/), but requesting
164 access and tagging your patches yourself will be helpful in the long
167 ## Address review comments, participate in discussion
169 Each change to Notmuch must be peer reviewed before it is accepted,
170 usually by one or two developers, depending on the impact of the
171 changes. You are expected to follow up on the review comments you
172 receive, either by discussing the comments and the code, or modifying
173 your patches. Again, see the [Notmuch mailing list
174 archives](http://notmuchmail.org/pipermail/notmuch/) for examples.
176 ## Send another round addressing review comments
178 If your patches need to be changed based on review (they usually do),
179 you need to make the changes and re-submit. `git rebase -i` is your
180 friend in updating your series. Also note that the upstream master may
181 have changed; be sure to rebase your updated changes on top of the
184 Once you have the updated series ready, send it to the mailing list
185 again. It will be helpful for others to use the
186 `--subject-prefix="PATCH vN"` option of `git format-patch` or
187 `git send-email` to add a version number of the patch series to the
188 subject (replacing vN with v2, v3, etc.) Use a cover letter (or, in
189 the case of a single patch, the notes after a "---" at the end of the
190 commit message) to summarize the main changes since the previous
191 version of the patch series. Also include the message-id reference of
192 the previous version.
194 Using the `--in-reply-to` option of `git format-patch` or
195 `git send-email` to send the patch series as a reply to the earlier
196 version is generally discouraged, particularly for large series, but
197 there are no hard rules. Usually the message-id reference to the
198 previous version is sufficient and preferred.
200 Tag the old patches obsolete in [nmbug](http://notmuchmail.org/nmbug/)
203 ## Review other people's work
205 You scratch my back and I'll scratch yours. It will be easier to get
206 people to review your patches if you review theirs.
210 Send bug reports to the Notmuch mailing list. Preferably prefix the
211 subject line with "BUG:" or similar. Tag the message as a bug in
212 [nmbug](http://notmuchmail.org/nmbug/).
214 Even better, send a patch adding a "known broken" test to the test suite
215 highlighting the issue.
217 ## Join the Notmuch IRC channel
219 Patch review happens on the Notmuch mailing list, but there is plenty of
220 discussion going on in the freenode #notmuch IRC channel. See
221 [freenode.net/irc_servers.shtml](http://freenode.net/irc_servers.shtml)
222 for information how to get there.