1 ============================= 2 Code Reviews with Phabricator 3 ============================= 4 5 .. contents:: 6 :local: 7 8 If you prefer to use a web user interface for code reviews, you can now submit 9 your patches for Clang and LLVM at `LLVM's Phabricator`_ instance. 10 11 While Phabricator is a useful tool for some, the relevant -commits mailing list 12 is the system of record for all LLVM code review. The mailing list should be 13 added as a subscriber on all reviews, and Phabricator users should be prepared 14 to respond to free-form comments in mail sent to the commits list. 15 16 Sign up 17 ------- 18 19 To get started with Phabricator, navigate to `http://reviews.llvm.org`_ and 20 click the power icon in the top right. You can register with a GitHub account, 21 a Google account, or you can create your own profile. 22 23 Make *sure* that the email address registered with Phabricator is subscribed 24 to the relevant -commits mailing list. If you are not subscribed to the commit 25 list, all mail sent by Phabricator on your behalf will be held for moderation. 26 27 Note that if you use your Subversion user name as Phabricator user name, 28 Phabricator will automatically connect your submits to your Phabricator user in 29 the `Code Repository Browser`_. 30 31 Requesting a review via the command line 32 ---------------------------------------- 33 34 Phabricator has a tool called *Arcanist* to upload patches from 35 the command line. To get you set up, follow the 36 `Arcanist Quick Start`_ instructions. 37 38 You can learn more about how to use arc to interact with 39 Phabricator in the `Arcanist User Guide`_. 40 41 Requesting a review via the web interface 42 ----------------------------------------- 43 44 The tool to create and review patches in Phabricator is called 45 *Differential*. 46 47 Note that you can upload patches created through various diff tools, 48 including git and svn. To make reviews easier, please always include 49 **as much context as possible** with your diff! Don't worry, Phabricator 50 will automatically send a diff with a smaller context in the review 51 email, but having the full file in the web interface will help the 52 reviewer understand your code. 53 54 To get a full diff, use one of the following commands (or just use Arcanist 55 to upload your patch): 56 57 * ``git diff -U999999 other-branch`` 58 * ``svn diff --diff-cmd=diff -x -U999999`` 59 60 To upload a new patch: 61 62 * Click *Differential*. 63 * Click *+ Create Diff*. 64 * Paste the text diff or browse to the patch file. Click *Create Diff*. 65 * Leave the Repository field blank. 66 * Leave the drop down on *Create a new Revision...* and click *Continue*. 67 * Enter a descriptive title and summary. The title and summary are usually 68 in the form of a :ref:`commit message <commit messages>`. 69 * Add reviewers and mailing 70 lists that you want to be included in the review. If your patch is 71 for LLVM, add llvm-commits as a Subscriber; if your patch is for Clang, 72 add cfe-commits. 73 * Leave the Repository and Project fields blank. 74 * Click *Save*. 75 76 To submit an updated patch: 77 78 * Click *Differential*. 79 * Click *+ Create Diff*. 80 * Paste the updated diff or browse to the updated patch file. Click *Create Diff*. 81 * Select the review you want to from the *Attach To* dropdown and click 82 *Continue*. 83 * Leave the Repository and Project fields blank. 84 * Add comments about the changes in the new diff. Click *Save*. 85 86 Reviewing code with Phabricator 87 ------------------------------- 88 89 Phabricator allows you to add inline comments as well as overall comments 90 to a revision. To add an inline comment, select the lines of code you want 91 to comment on by clicking and dragging the line numbers in the diff pane. 92 When you have added all your comments, scroll to the bottom of the page and 93 click the Submit button. 94 95 You can add overall comments in the text box at the bottom of the page. 96 When you're done, click the Submit button. 97 98 Phabricator has many useful features, for example allowing you to select 99 diffs between different versions of the patch as it was reviewed in the 100 *Revision Update History*. Most features are self descriptive - explore, and 101 if you have a question, drop by on #llvm in IRC to get help. 102 103 Note that as e-mail is the system of reference for code reviews, and some 104 people prefer it over a web interface, we do not generate automated mail 105 when a review changes state, for example by clicking "Accept Revision" in 106 the web interface. Thus, please type LGTM into the comment box to accept 107 a change from Phabricator. 108 109 Committing a change 110 ------------------- 111 112 Arcanist can manage the commit transparently. It will retrieve the description, 113 reviewers, the ``Differential Revision``, etc from the review and commit it to the repository. 114 115 :: 116 117 arc patch D<Revision> 118 arc commit --revision D<Revision> 119 120 121 When committing an LLVM change that has been reviewed using 122 Phabricator, the convention is for the commit message to end with the 123 line: 124 125 :: 126 127 Differential Revision: <URL> 128 129 where ``<URL>`` is the URL for the code review, starting with 130 ``http://reviews.llvm.org/``. 131 132 Note that Arcanist will add this automatically. 133 134 This allows people reading the version history to see the review for 135 context. This also allows Phabricator to detect the commit, close the 136 review, and add a link from the review to the commit. 137 138 Abandoning a change 139 ------------------- 140 141 If you decide you should not commit the patch, you should explicitly abandon 142 the review so that reviewers don't think it is still open. In the web UI, 143 scroll to the bottom of the page where normally you would enter an overall 144 comment. In the drop-down Action list, which defaults to "Comment," you should 145 select "Abandon Revision" and then enter a comment explaining why. Click the 146 Submit button to finish closing the review. 147 148 Status 149 ------ 150 151 Please let us know whether you like it and what could be improved! We're still 152 working on setting up a bug tracker, but you can email klimek-at-google-dot-com 153 and chandlerc-at-gmail-dot-com and CC the llvm-dev mailing list with questions 154 until then. We also could use help implementing improvements. This sadly is 155 really painful and hard because the Phabricator codebase is in PHP and not as 156 testable as you might like. However, we've put exactly what we're deploying up 157 on an `llvm-reviews GitHub project`_ where folks can hack on it and post pull 158 requests. We're looking into what the right long-term hosting for this is, but 159 note that it is a derivative of an existing open source project, and so not 160 trivially a good fit for an official LLVM project. 161 162 .. _LLVM's Phabricator: http://reviews.llvm.org 163 .. _`http://reviews.llvm.org`: http://reviews.llvm.org 164 .. _Code Repository Browser: http://reviews.llvm.org/diffusion/ 165 .. _Arcanist Quick Start: https://secure.phabricator.com/book/phabricator/article/arcanist_quick_start/ 166 .. _Arcanist User Guide: https://secure.phabricator.com/book/phabricator/article/arcanist/ 167 .. _llvm-reviews GitHub project: https://github.com/r4nt/llvm-reviews/ 168
