Get the Haiku Source Code / Pushing Patches to Haiku 101
Haiku’s source code is currently being hosted in a Git based repository with Gerrit code review. Anonymous access will allow anyone to download Haiku’s source code; However, the authenticated (non-anonymous) method is required for submitting patches.
Although most contributors tend to disclose their real names, we do not have a real name policy and a couple of contributors contribute to Haiku pseudonymously. That means that it’s possible for anyone to contribute.
Git Access - Anonymous testers
Build Tools:
git clone https://review.haiku-os.org/buildtools
Haiku:
git clone https://review.haiku-os.org/haiku
If you don’t care about the commit history and want to keep the download small,
try using the parameter --depth when cloning. --depth 10 limits the history
to the last 10 commits, for example.
Git Access - Contributors and patch submitters
Configure Git on your system:
Before making your first commit on a new system, be sure to configure Git. These global settings are stored in your git configuration directory (~/.git/ or for Haiku: ~config/settings/git/) and will be appended to each commit as your personal information.
git config --global user.name "John Doe"
git config --global user.email "john.doe@developers.com"
On macOS, you must set the following option in order to avoid problems with the unicode representation of filenames:
git config core.precomposeunicode true
Setup an account on Gerrit
Log in to Gerrit code review. You currently need a Github account for logging in.
Upload your SSH public key in Gerrit SSH keys settings page. If you don't have a key yet, you can generate one using ssh-keygen.
If the e-mail address used in your commits does not match the one in your github account, you will need to add and verify it in Gerrit E-Mail address settings.
Build Tools:
The <login>@ is only needed if your currently logged in username doesn’t match your review.haiku-os.org username.
git clone "ssh://<login>@git.haiku-os.org/buildtools" && scp -p <login>@git.haiku-os.org:hooks/commit-msg "buildtools/.git/hooks/"
Haiku:
The <login>@ is only needed if your currently logged in username doesn’t match your review.haiku-os.org username.
git clone "ssh://<login>@git.haiku-os.org/haiku"
scp -p <login>@git.haiku-os.org:hooks/commit-msg "haiku/.git/hooks/"
Switching from read-only to write access
Want to submit your first patch? Thanks, that’s great! You don’t need to checkout the sources again. Instead you can update your existing copy of the source to use the commiter access. Just change the remote URL:
git remote set-url origin ssh://<login>@git.haiku-os.org/haiku
You also should install the Gerrit hooks to generate Change-Ids:
scp -p <login>@git.haiku-os.org:hooks/commit-msg "haiku/.git/hooks/"
Some Notes
Case Sensitive Filesystem
Getting the source code through an HTTP proxy
Instead, use one of our mirror repositories at GitHub or Gitorious for anonymous HTTP access, they are both kept in sync with the main repository. First, set Git to connect through your proxy server:
git config --global http.proxy http://proxyuser:proxypwd@proxy.server.com:8080
Then clone the repositories from GitHub:
git clone http://github.com/haiku/buildtools.git
git clone http://github.com/haiku/haiku.git
Please note that these repositories do not contain any hrev tags, which are used by the Haiku build system to determine the Haiku revision. To work around this limitation, use the HAIKU_REVISION build variable when building Haiku.
Common tasks
If you are already familiar with the pull request workflow as used, for example, at GitHub, you can find an overview of the differences in Gerrit user’s manual.
Example git workflow
Updating the Sources
cd haiku
git pull --rebase
You can make git take care of this automatically for you, so that “git pull” does the right thing for Haiku:
cd haiku
git config pull.rebase true
Alternatively, a single path or multiple paths can be given to git pull. This will allow you to run the following command from any directory. This becomes extremely useful if you use an external object directory or if you wish to update both the buildtools and haiku directories at the same time.
git pull --rebase ./haiku ./buildtools
Making local commits
In Git, you make commits to your local tree, then push the final results to the central remote Haiku repository. Split your work in not too large commits, but remember that each commit will be reviewed separately, so don’t make them too small either.
The commit message will also be reviewed, and should describe the change in as much detail as possible. You can refer to other commits by either their hrev tag or their SHA1 hash, and to bugs using the #number notation. Gerrit and cgit will then automatically add an hyperlink to the relevant place.
The commit message should include a short description on the first line (ideally less than 64 characters), then a blank line, and a more detailed explanation. The short message is visible in “git log”, the web interface, and many other git tools, and allows to know what the commit is about. The details are available separately (for example in git log -p or when looking at the commit directly in the web interface), so they are both important.
Here is an example of a good commit message:
kernel: Perform the usual early morning tasks
* Ensure cats in computer are fed.
* Clean up white space.
* The retroencabulator needs to be adjusted to accept input from
multiple sources of data and ensure the buffer is free for
shenanigans.
* No functional change.
Short commit comment
If your commit is very short, you can include it directly on the Git command line:
git commit -a -m "WebPositive: Style cleanup, no functional change"
Long commit comments
If your commit message is longer, you can put it in a file and use it this way:
git commit -a -F ~/mycommitlog
Alternatively, you can use “git commit -a”, which will open a text editor and let you write down the message when you commit your changes.
It may be a good idea to check Gerrit as a point of reference if you are not sure how you should format your commit message.
Pushing changes for review
git push origin HEAD:refs/for/master -o topic="something"
After your changes are complete, the push command will push your local tree to the remote Haiku repository. The commits will be added to the review page and people will review them. You can then amend your commits and push them again, until they are reviewed and merged.
It is recommended to set a topic - a single keyword that can easily be searched for in the web interface and help categorize commits.
Taking review comments into account and updating a commit
Usually your changes will not be accepted on the first try. Other developers will review it, making sure they understand what you are doing, and maybe help you find better ways of doing it. They will also check that your code follows the coding guidelines, which are important to make sure the code is easy to read and uses the same conventions in all the codebase.
Single-commit change
To update an existing commit, you need to download it locally, modify it, and send it again. When your change consists of a single commit, you can cherry-pick it.
First make sure you start from a clean working tree with the latest Haiku changes (note that this will remove all your work-in-progress commits from the working copy - make sure these commits are in a branch. Git will remind you about this if you haven’t done so).
git fetch
git checkout origin/master
Then you can download your commit from Gerrit. To do this, use the Gerrit web interface and the Download -> Cherry Pick button, which allows you to copy the required git command. It looks like this, but it is different for each commit and each version of a commit so make sure to get the correct one from Gerrit:
git fetch "ssh://user@git.haiku-os.org/haiku" refs/changes/28/3228/4 && git cherry-pick FETCH_HEAD
You can now edit the files to make the needed changes. Once you are done, edit the commit to include your changes:
git add a/modified/file.cpp another/modified/file.h # you can use wildcards, or just 'git add .' to add everything modified
git commit --amend # modify the commit
Make sure the commit message contains the change-id for the commit. If it doesn’t, copy it from Gerrit and add it at the end of the commit message.
Finally, send your work for review:
git push origin HEAD:refs/for/master
HEAD:refs/for/master means that your change was built on top of the master
branch and that your changes are meant to be applied to the master branch.
Multiple-commit change
The process is similar when your change is split into multiple commits, but you can’t as easily use cherry-pick since it would have to be done once per commit. So, a different process can be used instead.
First of all make sure you have the latest version of the Haiku source code:
git fetch
Then go to the latest commit of your change in progress and use the Download -> Checkout menu to get all the changes at once. Again, note that the command changes for each commit, so be sure to get the correct one from Gerrit. The one below is only an example.
git fetch "ssh://user@git.haiku-os.org/haiku" refs/changes/99/1299/5 && git checkout FETCH_HEAD
You can then rebase your changes on the current version of Haiku:
git rebase origin/master
You can use git commit –amend to edit the latest commits and add more commits to the branch. To modify the previous commits, you need to use git interactive rebase (git rebase -i). See
git help rebasefor more help on rebasing.
Once you are done, you can update your patches on Gerrit:
git push origin HEAD:refs/for/master