This page describes the full process of submitting a patch to the Android Open Source Project (AOSP), including how to request a review and track your changes with Gerrit.
To start, ensure you've done the following:
- Initialized your build environment
- Downloaded the source
- Created a password using the password generator.
- For details about Repo and Git, see the Source Control Tools page.
- For information about different roles within the Android Open Source community, see the Project roles page.
- For licensing information about contributing code to the Android platform, see the Licenses page.
Authenticating with the server
If you share an IP address with other users, quotas can be triggered even for regular usage patterns. This can happen when, for example, many users sync new clients from the same IP address within a short time period. Authenticated access uses a separate quota for each user, regardless of IP address. To read about activating authenticated access, see Using authentication.
Starting a Repo branch
For each change that you intend to make, start a new branch within the relevant Git repository:
repo start NAME .
You can start several independent branches at the same time in the same
repository. The branch
NAME is local to your
workspace and isn't included either on Gerrit or in the final source tree.
Making your change
Modify the source files, and validate your changes.
Commit the changes to your local repository with these commands:
git add -A
git commit -s
Line 1: Headline
Provide a one-line summary (50 characters maximum)
This format is used by Git and Gerrit for various displays. It’s the most important, most dense part of your commit message. Consider using prefixes to describe the area you changed, followed by a description of the change you made in this commit, such as this one that has
uias the prefix:
ui: Removes deprecated widget
Line 2: Blank
Keep this line blank, always.
Line 3: Body
Write a longer description, starting on this line.
This must hard-wrap at 72 characters maximum. Describe what issue the change solves, and how. Although this is optional when implementing new features, it's very helpful to others later if they refer to this change, especially for debugging.
Include a brief note of any assumptions or background information that might be important when another contributor works on this feature.
A unique change ID and your name and email, which are provided during
repo init, are automatically added to your commit message.
Here's an example commit message:
Line 1, Headline - a short description Line 3, Body - Add the detailed description of your patch here. Use as many lines as needed. You can write an overall description, then list specifics. I6e3c64e7a:Added a new widget. I60c539a8f:Fixed the spinning image.To read a blog about good commit descriptions (with examples), see How to Write a Git Commit Message by Chris Beams.
Uploading to Gerrit
After you commit your change to your personal history, upload it to Gerrit with this command:
If you started multiple branches in the same repository, you're prompted to select which ones to upload.
After a successful upload, Repo provides you with the URL of a new page on Gerrit. Click the link that Repo gives you to view your patch on the review server, add comments, or request specific reviewers for your patch.
Requesting a review
After you've uploaded your changes to Gerrit, the patch must be reviewed
and approved by the appropriate code owners. Locate code owners in
To find the appropriate code owners and add them as reviewers for your change, follow these steps.
Select the SUGGEST OWNERS link in the Gerrit UI to see a list of code owners for the files in your patch.
Add code owners from the list as reviewers for your patch.
To determine the status of the files in your patch, check for the following icons next to the files in the patch.
- (checkmark icon): Approved by code owner
- (cross icon): Not approved by code owner
- (clock icon): Pending approval by code owner
Uploading a replacement patch
Suppose a reviewer looked at your patch and requested a small modification. You can amend your commit within Git, which results in a new patch on Gerrit that has the same change ID as the original.
git add -A
git commit --amend
When you upload the amended patch, it replaces the original both on Gerrit and in your local Git history.
Resolving sync conflicts
If other patches are submitted to the source tree that conflict with
yours, rebase your patch on top of the new
HEAD of the source
repository. To do so, run this command:
repo sync command fetches the updates from the source
server, then attempts to automatically rebase your
the new remote
If the automatic rebase is unsuccessful, perform a manual rebase.
Another tool for dealing with the rebase conflict is
git mergetool. When you've successfully merged the
conflicting files, run this command:
git rebase --continue
After either automatic or manual rebase is complete, run
repo upload to submit your rebased patch.
After a submission is approved
After a submission makes it through the review and verification process,
Gerrit automatically merges the change into the public repository. Other
users can run
repo sync to pull the update into their
respective local clients.
For upstream projects
Android makes use of a number of other open source projects, such as the
Linux kernel and WebKit, as described in
Android Software Management. For
most projects that reside under
external/, make the changes
upstream, then inform the Android maintainers of the new upstream release
that contains your changes.
You might also upload patches that cause a new upstream release to be tracked. Note that these can be difficult changes to make if the project is widely used within Android, like most of the larger ones mentioned below, which are usually upgraded with every release.
One interesting special case is Bionic. Much of the code there is from BSD, so unless the change is to code that's new to Bionic, please make an upstream fix, then a pull of a whole new file from the appropriate BSD.
Make all changes to the ICU project at
icu4j/ folders) on the
ICU-TC Home Page.
Submitting ICU Bugs and Feature Requests
for more. Add the label “android” to all upstream Jira requests.
Make all changes to LLVM-related projects (
external/llvm) on the
LLVM Compiler Infrastructure page.
Make all changes to the MirBSD Korn Shell project at
external/mksh either by sending an email to
miros-mksh on the
mirbsd.org domain (no
subscription required to submit there) or at
Make all changes to the OpenSSL project at
external/openssl on the
Make all changes to the WebKit project at
the WebKit page.
Start the process by
filing a WebKit bug. In the bug, use
Android for the
Platform and OS fields only if the bug
is specific to Android. Bugs are far more likely to receive the reviewers'
attention after a proposed fix is added and tests are included. See
Contributing Code to WebKit
Make all changes to the zlib project at
external/zlib on the
zlib home page.