Firefox for Android
Please read the Community Participation Guidelines and the Bugzilla Etiquette guidelines before filing an issue. This is our professional working environment as much as it is our bug tracker, and we want to keep our workspace clean and healthy.
Guide to Contributing (New contributors start here!)
Matrix: #fenix:mozilla.org channel (We're available Monday-Friday, GMT and PST working hours). Related channels:
Check out the project wiki for more information.
Localization happens on Pontoon. Please get in touch with delphine (at) mozilla (dot) com directly for more information.
Beginners! - Watch out for Issues with the "Good First Issue" label. These are easy bugs that have been left for first timers to have a go, get involved and make a positive contribution to the project!
We encourage you to participate in this open source project. We love Pull Requests, Bug Reports, ideas, (security) code reviews or any other kind of positive contribution.
Since we are a small team, however, we do not have the bandwidth to review unsolicited PRs. Please follow our Pull Request guidelines, or we may close the PR.
To make it easier to review, we have these PR requirements:
As a small team, we have to prioritize our work, and reviewing PRs takes time. We receive lots of PRs every day, so if you can keep your PRs small, it helps our small team review and merge code faster, minimizing stale code.
Keep in mind that the team is very overloaded, so PRs sometimes wait for a very long time. However this is not for lack of interest, but because we find ourselves in a constant need to prioritize certain issues/PRs over others. If you think your issue/PR is very important, try to popularize it by getting other users to comment and share their point of view.
Great! We encourage you to participate in this open source project. We love Pull Requests, Bug Reports, ideas, (security) code reviews or any other kind of positive contribution.
To make it easier to triage, we have these issue requirements:
Please keep in mind that even though a feature you have in mind may seem like a small ask, as a small team, we have to prioritize our planned work and every new feature adds complexity and maintenance and may take up design, research, marketing, product, and engineering time. We appreciate everyone’s passion but we will not be able to incorporate every feature request or even fix every bug. That being said, just because we haven't replied, doesn't mean we don't care about the issue, please be patient with our response times as we're very busy.
Pre-requisites: * Android SDK * To run command line tools, you'll need to configure Java: see our how-to guide.
git clone https://github.com/mozilla-mobile/fenix
./gradlew clean app:assembleDebug
If this errors out, make sure that you have an
ANDROID_SDK_ROOTenvironment variable pointing to the right path.
For general development, we recommend the debug build variant. Here's an explanation of each variant:
nightly, beta, and release are unsigned and
debuggable=falseby default. If you want these variants to be: - automatically signed, see Automatically signing release builds -
debuggable=true, see Building debuggable release variants
For accurate performance measurements, read this section!
To analyze performance during local development build a production variant locally (this could either be the Nightly, beta or release). Otherwise, you could also grab a pre-existing APK if you don't need to test some local changes. Then, use the Firefox profiler to profile what you need!
For more information on how to use the profiler or how to use the build, refer to this how to measure performance with the build
If you want to run performance tests/benchmarks in automation or locally use a production build since it is much closer in behavior compared to what users see in the wild.
Before you can install any release builds, You will need to sign production build variants: see Automatically signing release builds for details.
Some features are disabled by default when Fenix is built locally. This can be problematic at times for checking performance since you might want to know how your code behaves with those features. The known features that are disabled by default are: - Sentry - Adjust - Mozilla Location Services (also known as MLS) - Firebase Push Services - Telemetry (only disabled by default in debug builds) - Nimbus
To reduce review turn-around time, we'd like all pushes to run tests locally. We'd recommend you use our provided pre-push hook in
config/pre-push-recommended.sh. Using this hook will guarantee your hook gets updated as the repository changes. This hook tries to run as much as possible without taking too much time.
Before you can run the hook, you'll need to configure Java properly because it relies on command line tools: see our how-to guide.
To add it on Mac/Linux, run this command from the project root:
sh ln -s ../../config/pre-push-recommended.sh .git/hooks/pre-pushor for Windows run this command using the Command Prompt with administrative privileges:
sh mklink .git\hooks\pre-push ..\..\config\pre-push-recommended.shor using PowerShell:
sh New-Item -ItemType SymbolicLink -Path .git\hooks\pre-push -Value (Resolve-Path config\pre-push-recommended.sh)
To push without running the pre-push hook (e.g. doc updates):
sh git push --no-verify
Note: If while pushing you encounter this error "Could not initialize class org.codehaus.groovy.runtime.InvokerHelper" and are currently on Java14 then downgrading your Java version to Java13 or lower can resolve the issue
Steps to downgrade Java Version on Mac with Brew: 1. Install Homebrew (https://brew.sh/) 2. run
brew update3. To uninstall your current java version, run
sudo rm -fr /Library/Java/JavaVirtualMachines/4. run
brew tap homebrew/cask-versions5. run
brew search java6. If you see java11, then run
brew install java117. Verify java-version by running
You can speed up local development by setting a few helper flags available in
local.properties. Some flags will make it easy to work across multiple layers of the dependency stack - specifically, with android-components, geckoview or application-services.
To sign your release builds with your debug key automatically, add the following to
With this line, release build variants will automatically be signed with your debug key (like debug builds), allowing them to be built and installed directly through Android Studio or the command line.
This is helpful when you're building release variants frequently, for example to test feature flags and or do performance analyses.
Nightly, Beta and Release variants are getting published to Google Play and therefore are not debuggable. To locally create debuggable builds of those variants, add the following to
To set the raptor manifest flag in Nightly, Beta and Release variants, add the following to
If you're making changes to these projects and want to test them in Fenix, auto-publication workflow is the fastest, most reliable way to do that.
local.properties, specify a relative path to your local
application-servicescheckouts. E.g.: -
Once these flags are set, your Fenix builds will include any local modifications present in these projects.
In order to build successfully, you need to check out a commit in the dependency repository that has no breaking changes. The two best ways to do this are: - Run the
/tools/list_compatible_dependency_versions.pyscript to output a compatible commit - Check out the latest commit from main in this repository and the dependency repository. However, this may fail if there were breaking changes added recently to the dependency.
If you're working with the Nimbus experiments platform, by default for local development Fenix configures Nimbus to not use a server.
If you wish to use a Nimbus server during local development, you can add a
file://endpoint to the
Testing experimental branches should be possible without a server.
Specify a relative path to your local
dependencySubstitutions.geckoviewTopsrcdir, and optional a path to m-c object directory via
If these are configured, local builds of GeckoView will be used instead of what's configured in Dependencies.kt. For more details, see https://firefox-source-docs.mozilla.org/mobile/android/geckoview/contributor/geckoview-quick-start.html#include-geckoview-as-a-dependency
See notes on building successfully in the
This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/