CONTRIBUTING.md

   1 # LTTng-UST contributor's guide
   2
   3 Being an open source project, the LTTng-UST project welcomes
   4 contributions from anyone. This guide walks you through the process
   5 of contributing a patch to LTTng-UST.
   6
   7
   8 ## Getting the source code
   9
  10 The LTTng-UST project uses [Git](https://git-scm.com/) for version
  11 control. The upstream Git repository URL is:
  12
  13     git://git.lttng.org/lttng-ust.git
  14
  15
  16 ## Coding standard
  17
  18 LTTng-UST uses the
  19 [Linux kernel coding style](http://www.kernel.org/doc/Documentation/CodingStyle).
  20
  21 Although the LTTng-UST code base is primarily written in C, it does
  22 contain shell, Perl, and Python code as well. There is no official coding
  23 standard for these languages. However, using a style consistent with the
  24 rest of the code written in that language is strongly encouraged.
  25
  26
  27 ## Creating and sending a patch
  28
  29 LTTng-UST's development flow is primarily email-based, although we
  30 also accept pull requests on our
  31 [GitHub mirror](https://github.com/lttng/lttng-ust). If you're going
  32 to create GitHub pull requests, make sure you still follow the
  33 guidelines below.
  34
  35 Like a lot of open source projects, patches are submitted and reviewed
  36 on its development mailing list,
  37 [`lttng-dev`](http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev)
  38 (`lttng-dev@lists.lttng.org`). The mailing list is also used to share
  39 and comment on <abbr title="Request for Comments">RFC</abbr>s and answer
  40 user questions.
  41
  42 Once your changes have been committed to your local branch, you may use
  43 Git's [`format-patch`](https://git-scm.com/docs/git-format-patch) command
  44 to generate a patch file. The following command line generates a
  45 patch from the latest commit:
  46
  47     git format-patch -N1 -s --subject-prefix="PATCH lttng-ust"
  48
  49 The custom `PATCH lttng-ust` subject prefix is mandatory when
  50 submitting patches that apply to the LTTng-UST project.
  51
  52 The patch's subject (the commit message's first line) should:
  53
  54   * begin with an uppercase letter
  55   * be written in the present tense
  56   * _not_ exceed 72 characters in length
  57   * _not_ end with a period
  58   * be prefixed with `Fix:` if the commit fixes a bug
  59
  60 The commit message's body should be as detailed as possible and explain
  61 the reasons behind the proposed change. Any related
  62 [bug report(s)](https://bugs.lttng.org/projects/lttng-ust/issues)
  63 should be mentioned at the end of the message using the `#123` format,
  64 where `123` is the bug number:
  65
  66   * Use `Refs: #123` if the patch is related to bug 123, but does not
  67     fix it yet.
  68   * Use `Fixes: #123` to signify that this patch fixes the bug.
  69
  70 Make sure to **sign-off** your submitted patches (the `-s` argument to
  71 Git's `commit` and `format-patch` commands).
  72
  73 Here's a complete example:
  74
  75 ~~~ text
  76 Fix: use this instead of that in some context
  77
  78 Ball tip jowl beef ribs shankle, leberkas venison turducken tail pork
  79 chop t-bone meatball tri-tip. Tongue beef ribs corned beef ball tip
  80 kevin ground round sausage rump meatloaf pig meatball prosciutto
  81 landjaeger strip steak. Pork pork belly beef.
  82
  83 Biltong turkey porchetta filet mignon corned beef. T-bone bresaola
  84 shoulder meatloaf tongue kielbasa.
  85
  86 Fixes: #321
  87 Refs: #456
  88 Refs: #1987
  89
  90 Signed-off-by: Jeanne Mance <jmeance@lttng.org>
  91 ~~~
  92
  93 Please note that patches should be **as focused as possible**. Do not,
  94 for instance, fix a bug and correct the indentation of an unrelated
  95 block of code as part of the same patch.
  96
  97 Once you are confident your patch meets the required guidelines,
  98 you may use Git's [`send-email`](https://git-scm.com/docs/git-send-email)
  99 command to send your patch to the mailing list:
 100
 101     git send-email --suppress-cc=self --to lttng-dev@lists.lttng.org *.patch
 102
 103 Make sure you are
 104 [subscribed](http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev)
 105 to the mailing list to follow and take part in discussions about your
 106 changes. You may join the file to an email as an attachment if you can't
 107 send the patch directly using <code>git&nbsp;send&#8209;email</code>.
 108
 109
 110 ## Reviews
 111
 112 Once your patch has been posted to the mailing list or as a GitHub
 113 pull request, other contributors may propose modifications.
 114 This is completely normal. This collaborative code review is an integral
 115 part of the open source development process in general and LTTng-UST
 116 makes no exception.
 117
 118 Keep in mind that reviewing patches is a time-consuming process and,
 119 as such, may not be done right away. The delays may be affected by the
 120 current release cycle phase and the complexity of the proposed changes.
 121 If you think your patch might have been forgotten, please mention it on
 122 the [`#lttng`](irc://irc.oftc.net/lttng) IRC channel rather than
 123 resubmitting.
 124
 125
 126 ## Release cycle
 127
 128 The LTTng-UST project follows a release cycle that alternates between
 129 development and release candidate (RC) phases. The master branch is
 130 feature-frozen during RC phases: only bug fixes are accepted during
 131 this period. However, patches adding new functionality may still be
 132 submitted and reviewed during the RC. The upcoming features and release
 133 dates are posted in a monthly digest on the mailing list.