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