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Effective in 2026, to align with our trunk stable development model and ensure platform stability for the ecosystem, we will publish source code to AOSP in Q2 and Q4. For building and contributing to AOSP, use android-latest-release. The android-latest-release manifest branch will always reference the most recent release pushed to AOSP. For more information, see Changes to AOSP.
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Set feature launch flag values
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By default, all feature launch flags are READ_WRITE and set to DISABLED.
Before you can test a feature, you must override the default value used in the
build by creating a flag values file for the flag. In a flag values file,
you set a individual flag's state (ENABLED or DISABLED) and permission
(READ_WRITE or READ_ONLY).
A release configuration is a directory that contains all of the flag values
files for a specific build of Android (with certain features enabled and
disabled).
AOSP ships with a few release configurations, such as trunk_staging.
Release configuration directories are found under
WORKING_DIRECTORY/build/release/aconfig/.
Note: This page shows you how to add a flag to an existing release configuration
as a means of teaching how release configurations work. The release
configurations included in AOSP are defined by Google.
Google doesn't accept contributions to update or change a configuration's
feature release flags. Instead, you can define your own custom release
configurations including default flag values in your forks of AOSP. For more
information on release configurations, see
Set feature launch flag values.
When you use the lunch command to
choose a target, you're
also setting the release configuration for the target.
For example, the
following is a trunk_staging target:
lunch aosp_cf_x86_64_only_phone-trunk_staging-userdebug
Trunk staging is a development release configuration because
Google uses it to test features before general release. This configuration
uses
mostly READ_WRITE flags that let you test your code with features enabled or
disabled at runtime.
At general release, use a release release configuration. A release
release configuration mostly uses READ_ONLY flags and reflects all of the code
enabled for that release.
Add a flag to the trunk_staging release configuration
To test a new flag, add it to the trunk_staging release configuration as
follows:
Navigate to WORKING_DIRECTORY/build/release/aconfig/trunk_staging/
Create a directory with the same package name as your flag, such as
com.example.android.aconfig.demo.flags shown in
Declare an aconfig flag for Java.
Navigate to the new directory.
In the directory, create a flag values file that combines the name used in
the flag declaration (.aconfig) file, such as my_static_flag shown in
Declare an aconfig flag for Java
with _flag_values.textproto. The resulting filename is
my_static_flag_flag_values.textproto.
Edit the file and add a flag_value similar to the following:
flag_value {
package: "com.example.android.aconfig.demo.flags"
name: "my_static_flag"
state: DISABLED
Permission: READ_WRITE
}
Where:
package contains the same package name used in the declaration.
name contains the same name used in the declaration.
state is either ENABLED or DISABLED.
permission is either READ_WRITE or READ_ONLY. Generally, the
permission is set to READ_ONLY for flag values files that are part of a
release configuration.
Save the file and exit your editor.
In the same directory as the flag values file, create a build file called
Android.bp. This file is used to include the flag values file in the build.
In the Android.bp file, create a aconfig_values section similar to:
aconfig_values {
name: "aconfig-values-platform_build_release-trunk-staging-com.example.android.aconfig.demo.flags-all",
package: "com.example.android.aconfig.demo.flags",
srcs: [
"*_flag_values.textproto",
]
}
Where:
name is the unique name for the Soong build module. Google uses the
convention of
aconfig-values-platform_PATH_TO_RELEASE_CONFIG_DIR-CONFIG_NAME-package.name-all.
This name must must match the name that soong auto-generates
based on the aconfig_value_set declaration in the parent directory's
Android.bp file. Note that
PATH_TO_RELEASE_CONFIG_DIR is build_release.
package contains the same package name used in the declaration.
srcs is a list of all of your flag values files.
Save the file and exit your editor.
Navigate to the directory above the current directory (cd ..)
Build Android, and run your new code to verify that it's enabled per the
setting in the flag values file.
Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
Last updated 2026-06-17 UTC.
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