Notes for Maintainers

Core ActiveMQ Artemis members have write access to the Apache ActiveMQ Artemis repositories and will be responsible for acknowledging and pushing commits contributed via pull requests on GitHub.

Core ActiveMQ Artemis members are also able to push their own commits directly to the canonical Apache repository. However, the expectation here is that the developer has made a good effort to test their changes and is reasonably confident that the changes that are being committed will not break the build.

What does it mean to be reasonably confident? If the developer has run the same maven commands that the pull-request builds are running they can be reasonably confident. Currently the PR build runs this command:

mvn -Pfast-tests -Pextra-tests install

However, if the changes are significant, touches a wide area of code, or even if the developer just wants a second opinion they are encouraged to engage other members of the community to obtain an additional review prior to pushing. This can easily be done via a pull request on GitHub, a patch file attached to an email or JIRA, commit to a branch in the Apache git repo, etc. Having additional eyes looking at significant changes prior to committing to the main development branches is definitely encouraged if it helps obtain the "reasonable confidence" that the build is not broken and code quality has not decreased.

If the build does break then developer is expected to make their best effort to get the builds fixed in a reasonable amount of time. If it cannot be fixed in a reasonable amount of time the commit can be reverted and re-reviewed.

Using the dev profile.

Developers are encouraged also to use the Dev profile, which will activate checkstyle during the build:

mvn -Pdev install

Commit Messages

Please ensure the commit messages follow the 50/72 format as described here. This format follows the recommendation from the official Git book.

Configuring git repositories

Aside from the traditional origin and upstream repositories committers will need an additional reference for the canonical Apache git repository where they will be merging and pushing pull-requests. For the purposes of this document, let's assume these ref/repo associations already exist as described in the Working with the Code section:

• origin : https://github.com/(your-user-name)/activemq-artemis.git

• upstream : https://github.com/apache/activemq-artemis

• Add the canonical Apache repository as a remote. Here we call it apache.

   $ git remote add apache https://gitbox.apache.org/repos/asf/activemq-artemis.git
  

• Add the following section to your /.git/config statement to fetch all pull requests sent to the GitHub mirror. We are using upstream as the remote repo name (as noted above), but the remote repo name may be different if you choose. Just be sure to edit all references to the remote repo name so it's consistent.

   [remote "upstream"]
       url = git@github.com:apache/activemq-artemis.git
       fetch = +refs/heads/*:refs/remotes/upstream/*
       fetch = +refs/pull/*/head:refs/remotes/upstream/pr/*
  

Merging and pushing pull requests

Here are the basic commands to retrieve pull requests, merge, and push them to the canonical Apache repository:

1. Download all the remote branches etc... including all the pull requests.

    $ git fetch --all
    Fetching origin
    Fetching upstream
    remote: Counting objects: 566, done.
    remote: Compressing objects: 100% (188/188), done.
    remote: Total 566 (delta 64), reused 17 (delta 17), pack-reused 351
    Receiving objects: 100% (566/566), 300.67 KiB | 0 bytes/s, done.
    Resolving deltas: 100% (78/78), done.
    From github.com:apache/activemq-artemis
     * [new ref]         refs/pull/105/head -> upstream/pr/105
   

2. Checkout the pull request you wish to review

    $ git checkout pr/105 -B 105
   

3. Rebase the branch against master, so the merge would happen at the top of the current master

    $ git pull --rebase apache master
   

4. Once you've reviewed the change and are ready to merge checkout master.

    $ git checkout master
   

5. Ensure you are up to date on your master also.

    $ git pull --rebase apache master
   

6. We actually recommend checking out master again, to make sure you wouldn't add any extra commits by accident:

    $ git fetch apache
    $ git checkout apache/master -B master
   

7. Create a new merge commit from the pull-request. IMPORTANT: The commit message here should be something like: "This closes #105" where "105" is the pull request ID. The "#105" shows up as a link in the GitHub UI for navigating to the PR from the commit message. This will ensure the github pull request is closed even if the commit ID changed due to eventual rebases.

    $ git merge --no-ff 105 -m "This closes #105"
   

8. Push to the canonical Apache repo.

    $ git push apache master
   

Using the automated script

If you followed the naming conventions described here you can use the scripts/rebase-PR.sh script to automate the merging process. This will execute the exact steps described on this previous section.

• Simply use:

$ <checkout-directory>/scripts/merge-pr.sh <PR number> Message on the PR

Example:

$  pwd
/checkouts/apache-activemq-artemis

$  ./scripts/merge-PR.sh 175 ARTEMIS-229 address on Security Interface

The previous example was taken from a real case that generated this merge commit on #175.

• After this you can push to the canonical Apache repo.

  $ git push apache master
  

Use a separate branch for your changes

It is recommended that you work away from master for two reasons:

1. When you send a PR, your PR branch could be rebased during the process and your commit ID changed. You might get unexpected conflicts while rebasing your old branch.

2. You could end up pushing things upstream that you didn't intend to. Minimize your risks by working on a branch away from master.

Notes:

The GitHub mirror repository (i.e. upstream) is cloning the canonical Apache repository. Because of this there may be a slight delay between when a commit is pushed to the Apache repo and when that commit is reflected in the GitHub mirror. This may cause some difficulty when trying to push a PR to apache that has been merged on the out-of-date GitHub mirror. You can wait for the mirror to update before performing the steps above or you can change your local master branch to track the master branch on the canonical Apache repository rather than the master branch on the GitHub mirror:

$ git branch master -u apache/master

Where apache points to the canonical Apache repository.

If you'd like your local master branch to always track upstream/master (i.e. the GitHub mirror) then another way to achieve this is to add another branch that tracks apache/master and push from that branch e.g.

$ git checkout master
$ git branch apache_master --track apache/master
$ git pull
$ git merge --no-ff pr/105
$ git push