(Forked from another bug)

The package attribute in the source AndroidManifest.xml is used to namespace the R class, resolve any relative class names declared in the AndroidManifest.xml, and namespace the BuildConfig class; see here.

Instead of getting this value from the manifest, AGP should add namespace to BaseExtension and testNamespace to TestedExtesion, which devs could use like so:

android {
    namespace "com.example.foo"
    testNamespace "com.example.foo.test"
}

Eventually namespace should be required to be specified via the DSL, with no option to specify it via the package attribute in the AndroidManifest.xml. Here's a rough possible timeline:

AGP 7.0 - Add DSL and prefer to get values there instead of from the manifest
AGP 7.1 - Move value from AndroidManifest.xml to DSL via upgrade wizard
AGP 7.3 - Warn if a package attribute is found in the source manifest.
AGP 8.0 - ~~Don't allow package attribute in source AndroidManifest.xml~~ Require namespace to be set via the DSL