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Overview

The Asterisk project uses Gerrit for code reviews, continuous integration validation, and git management. When creating a patch to Asterisk or its various related projects, all patches should be pushed to Gerrit for review.

Use of Gerrit is beyond the scope of this wiki page - for in depth information, see the Gerrit documentation.

Creating an Account

Gerrit uses OpenID in conjunction with the Asterisk project's Atlassian infrastructure to provide single sign-on. If you already have an account in the Asterisk project infrastructure (such as JIRA) and have signed a Contributor License Agreement, you should be able to sign in to Gerrit automatically.

  1. Create an account at signup.asterisk.org.

  2. Sign a Contributor License Agreement.

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    Until your Contributor License Agreement is approved, you will not be able to sign into the project OpenID provider or Gerrit.

  3. Browse to Gerrit, and click Sign In.

  4. This will redirect to openid.asterisk.org. Sign in with your Atlassian username/password.

  5. Upon signing in successfully, you will need to authorize Gerrit to access your OpenID. When you have done so, you should be redirected back to Gerrit, and will be signed in.

Setting up your Gerrit Account

Upon logging in for the first time, you will need to perform the following:

  1. Set your username for your account. This can be any username, although we highly recommend matching your Atlassian username. To set your username:
    1. Click on your name in the top-right corner.
    2. Click "Settings"
    3. Click "Profile" on the left side of the screen.
    4. In the top text box in the center, enter your user name, and confirm.

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      Failure to set your username will result in clones using SSH failing, despite adding your SSH key. If you can not clone using SSH please ensure you have set your username.

  2. Add your SSH public key.

Setting up your environment

Creating an SSH Alias

Since access to gerrit.asterisk.org is likely to occur often if you're submitting patches, you may want to set up an SSH alias:

This will allow you to access the repository as shown below:

Install git-review

You can skip this step if you're only downloading patches for testing.

Most Gerrit users will be submitting patches for review and will need the git review command.  It's not normally installed by default when you install git so it must be installed separately.  The package is called git-review and should be available via most package managers.  If not, you can install it using pip: 

Install git-review from git

Prepare git

You can skip this step if you're only downloading patches for testing.

In every repository you plan on submitting patches from, you'll need to set your email to match that expected by Gerrit.  You can set it in each repository after you've cloned it or you can set it globally.

Set per repository
Set globally

Cloning from Gerrit

While access to the underlying git repository is open to anyone via anonymous HTTP access, this guide will assume that you want to push changes up as well. For that, Gerrit uses SSH. If you are only looking to obtain the source code for a particular repository, clone it from the Official Asterisk GitHub Mirror

Clone the repository:

Clone using full SSH URL

or

Clone using SSH alias

You can also clone and check out a branch in one step

Clone asterisk and check out branch 13

If you're only retrieving patches and don't need to submit, you can clone from https:

Clone using Anonymouns HTTPS

To push reviews to Gerrit, you'll need the commit hook that generates the Gerrit Change-Id and appends it to every commit message.  You can install the hook easily with git review.

Install the Gerrit commit hook

It's imperative that once a Change-Id is added to a review it's not changed.  Gerrit uses it to associate multiple commits with a single review and associate cherry-picks among branches.

Gerrit Review Submit Workflow

Now that the repository is set up, it's time to do some real work!  Let's say you have a change you wish to make against the Asterisk 13 branch.

Get an Asterisk Issue ID

There should be an Asterisk issue open for every change you submit.  If you don't have one already, create a new issue at https://issues.asterisk.org.  Let's say you're using ASTERISK-12345.

Create a working branch in your repository

You'll want to keep the local branches that track remote branches, like 13, 14 and master, in a pristine condition so create a new working branch that's based on the remote branch you're making the change against.  Using the Asterisk issue id as the branch name will make things easier later on.  You should always start your change in the oldest branch to which the change will apply which is 13 in this example.

Do Some Work!

Test Your Work!

When you submit your review, it will automatically be built and the Asterisk unit tests run so to save re-work time, you should run the Asterisk unit tests against your changes before you submit.  To do so, configure asterisk with the --enable-dev-mode flag and enable TEST_FRAMEWORK in menuselect.  After installing Asterisk in your test environment (and you should have a test environment), you can run the tests from the Asterisk CLI with the test execute all command.  

If you have the Asterisk Testsuite installed, running the test suite is also recommended since it will be run against your change before the change is merged.  See Installing the Asterisk Test Suite for more information.

Commit

You have to commit before you submit and the commit message is crucial.  For more information about commit messages, see Commit Messages.  You'll notice that when you edit the commit message, you'll see that the Gerrit Change-Id was automatically added to the end.  DON'T ALTER OR REMOVE IT!!  You'll see why this is important later.

Here's a quick sample commit message:

Submit

Submitting is easy:

Submit a patch for review

13 represents the branch you're submitting this patch against.  The default is master so don't forget to specify it.  

If the submit is successful, you'll see a confirmation that looks like so:

9999 is the review number.

Cherry Pick

If you're making your change to the Asterisk 13 or 14 branches, you'll probably need to cherry-pick your change to other branches.  For changes to 13, cherry-pick to 14 and master.  For changes to 14, cherry-pick to master.  The easiest way to do this is via the Gerrit web user interface.

  1. Log into Gerrit at http://https://gerrit.asterisk.org and open your change.  Notice that the change topic is set to ASTERISK-12345.  This was automatically set because the name of the working branch you submitted from was ASTERISK-12345.   If it's not set correctly to the Asterisk issue id, set it now.   If you don't use the Asterisk issue id as the working branch name, you can set the topic when you submit using the -t option to git review as follows: git review -t ASTERISK-12345 13

  2. Whenever possible, you should cherry pick from the oldest branch to the newest in order.  Click the Cherry Pick button and choose the destination branch.  Assuming the change was originally submitted against 13, choose 14 and click the Cherry Pick Change button.  Gerrit will create a new review for you against the destination branch.  Notice though that Gerrit altered the Topic by appending the destination branch.  You'll need to reset it to just the Asterisk issue id.  Once that's done, click Cherry Pick again and repeat the process for the master branch.  You'll get new review numbers for each cherry-pick of course.

You can cherry-pick a review from the command line if you so wish:

Cherry pick a review from the command line

This will cherry pick review 9999 to the 14 branch.

Watch for verification

As each review is created, Gerrit will automatically schedule a verification step with Jenkins (our continuous integration platform).  To pass the verification, Asterisk has to build successfully with your change and all unit tests must pass.  Passing is usually the signal to reviewers that it's a valid patch and they can spend time reviewing it.  If it fails, it's up to you to examine the results by following the links that Jenkins added to the comments and taking appropriate action.
 

Respond to comments

The worst thing you can do is push a review then not respond to comments!.  This tells reviewers that the review isn't important to you and the review will probably keep falling further back in the queue.

Next Steps

If your review is accepted without the need for re-work, you need to nothing further.  Otherwise, read on.

Updating a Review

Making updates to a review is a bit tricky because you don't want to create new commits or new reviews with each update.  Here are the steps:

Pull down the current review

This will create (or reuse) a branch named "review/<your_name>/<topic>" and switch you to it.  In this example and assuming your name is "Joe Developer", the branch would be "review/joe_developer/ASTERISK-12345".

Make and test your changes

If you wind up adding a file, don't forget to do a git add <filename> on the new file.

Amend the original commit

Amend a commit

It is CRITICAL that you amend your original commit and not create a new commit.  Failing to amend will generate a new Change-Id and will cause Gerrit to create a NEW review instead of creating a new patchset on the existing review.

Re-submit

Don't forget the base branch.

Cherry Pick

As with the initial submit, cherry-pick to the other applicable branches. 

If you have to make multiple changes over the lifetime of the review, you should always download the same review, 9999 in this case.  This is because the branch name that gets generated for the review doesn't include the base branch.  In our example, let's say you got review 10000 when you cherry-picked 9999 to the 14 branch.  If you do git review -d 9999 then later do git review -d 10000, you'll get a warning from git that the base branches aren't the same.  If this happens, check out another branch temporarily, delete the review branch, then download the review again.

Advanced Topics

What do do when a cherry-pick fails, etc.  Coming Soon!

Team Branches

The repositories on Gerrit typically require all changes in all of the mainline branches to be reviewed prior to merging. While this is appropriate for the mainline branches, sometimes, it is useful to have a branch on the central server that multiple developers can use for collaboration. These branches exist within a special branch namespace, team. Registered Gerrit users have the ability to manipulate branches within that namespace directly, bypassing the usual Gerrit code review process.

Posting For Peer Review

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When a code change in a team branch is ready for peer review, using the git review tool or pushing the change to Gerrit's refs/for/[branch] will still automatically post it for review on Gerrit. The instructions on this page assume that developers wanting to use team branches want to perform some development collaboratively without posting the change for review.

For instruction on posting a change for review, see Pushing to Gerrit for Code Review.

Team Branch Manipulation in Gerrit

Creating a new Team Branch

Creating a new team branch can be done at any time from a local branch. For example, to create a new team branch from local master:

 Check out a Team Branch

Checking out a team branch is done in the same way as a mainline branch:

Pushing to a Team Branch

Pushing to a team branch can be done directly. This bypasses Gerrit's peer review. Note that team branches can be peer reviewed if desired, using the same mechanism as a 'normal' Gerrit peer review.

Delete a Team Branch

Deleting a team branch is done by pushing an empty local branch (nothing) to the team branch. Note that you have to use git push --force.

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It should go without saying, but be careful when deleting a team branch. All registered users have access rights to the team area - as such, anyone can affect someone else's team branch.

Recovering a Subversion Team Branch

While the Subversion Team branches were moved over to Git with their entire history, much of that history typically consists of Automerge commits. These commits are not well understood by Git; from Git's perspective, they are completely independent from the mainline commits they merged over. This can cause a "standard" rebase to fail miserably: the rebase will not realize that the Automerge commits are identical to those on the branch being rebased to. As a result, you'll often have a lot of merge conflicts if you attempt to rebase directly.

While working through the merge conflicts in a rebase is an option, an easier approach may be to simply re-build the branch on the current state of the mainline branch it wants to track. This example walks through that process, performing a rebase of branch team/mjordan/trunk-http-stuff-and-things on top of master.

  1. Checkout the subversion team history branch into a temporary local branch:

  2. Determine the useful commits to pull over. In this case, we're going to skip:
    1. All commits from Automerge script.
    2. All commits that modify Subversion properties or create Subversion branches.

      In the above screenshot, we want the three commits from Matthew Jordan between the Automerge: script automerge cancel and the Matthew Jordan: Re-enable automerge.
    3. Record the hashes of the commits you want to carry-over.
  3. Checkout a new branch for your work, tracking whatever canonical mainstream branch is appropriate:

  4. Cherry-pick each commit over, solving merge conflicts as necessary:

  5. If desired, fix up any history:

  6. Remove the temporary branch:

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    You may get the following warning:

    That's okay. You don't want to merge the whole thing to HEAD, as the Automerge script commits are duplicates of commits already in HEAD.

  7. Push the branch up to your team branch location:

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    In this example, a new team branch is being made - team/mjordan/http-caching. This way, if something is missed in the cherry-picks, I haven't blown away my Subversion branch.

Troubleshooting

git-review

Problem: attempting to run git review results in something like the following:

Traceback (most recent call last):
  File "/usr/local/bin/git-review", line 11, in <module>
    sys.exit(main())
  File "/usr/local/lib/python2.6/dist-packages/git_review/cmd.py", line 1132, in main
    (os.path.split(sys.argv[0])[-1], get_version()))
  File "/usr/local/lib/python2.6/dist-packages/git_review/cmd.py", line 180, in get_version
    provider = pkg_resources.get_provider(requirement)
  File "/usr/lib/python2.6/dist-packages/pkg_resources.py", line 176, in get_provider
    return working_set.find(moduleOrReq) or require(str(moduleOrReq))[0]
  File "/usr/lib/python2.6/dist-packages/pkg_resources.py", line 648, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python2.6/dist-packages/pkg_resources.py", line 546, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: git-review

Solution: Run

$ sudo pip install --upgrade setuptools

on your command line

Problem: attempting to run git review results in "unpack failed: error Missing tree":

Description:  There is an incompatibility between certain version of git and gerrit that causes this error when the commit to be pushed was amended and only the commit message changed.
Solution:  Run git push manually with the --no-thin option:

$ git push --no-thin asterisk:{repo} HEAD:refs/for/master

Problem:  Unable to login to gerrit.asterisk.org

Solution: Until your Contributor License Agreement is approved, you will not be able to sign into the project OpenID provider or Gerrit. See the "Creating an Account" section for instructions on how to resolve this.

Problem:  Unable to unsubscribe from Gerrit notifications

Solution: You may have mistaken the Gerrit notifications on a mailing list for notifications associated with your account. Of course if the notifications are being received via a mailing list then you would need to unsubscribe from the entire mailing list to stop receiving related mailings.

Other possibilities are that you have multiple accounts or are receiving notifications via forwarding from another E-mail address.

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  1. I thinks a other point add in this page is for resolve conflict, a good explain http://www.mediawiki.org/wiki/Gerrit/resolve_conflict

    Other things is to use "git review -d ID_REVIEW" for update the change of review. This create a branch from the git repository with change. After the change i use