Root cause found, and it is not the stale build cache I claimed earlier.
flutter clean was good hygiene and changed nothing here, because nothing
was cached: the resources were being deliberately removed.
Flutter's own Gradle plugin enables shrinking on every release build --
FlutterPlugin.kt, `releaseBuildType.isMinifyEnabled = true` and
`isShrinkResources = true` -- no matter what app/build.gradle.kts says. The
shrinker keeps what it can see referenced, and it cannot see
`MediaControl.custom(androidIcon: 'drawable/ic_auto_eq_on')`: that is a
string inside Dart, resolved at runtime through getIdentifier. So both
equalizer icons were stripped from every release APK ever built.
The evidence that pins it, from the APK pulled off the device:
ic_stat_pluriwave present <- referenced as R.drawable from Kotlin,
4 call sites in the alarm notifications
ic_auto_eq_on absent <- named only in a Dart string
ic_auto_eq_off absent <- named only in a Dart string
Same folder, same file shape, same commit range. The only difference is
whether a real R.drawable reference exists, which is exactly what the
shrinker looks for.
The consequence was never a blank button. getResourceId returns 0 for an
unresolvable name, PlaybackStateCompat.CustomAction.Builder throws on a 0
icon, and that throw aborts AudioService.setState before the media session
is activated -- so Android Auto held a frozen, inactive session. Dead
playback screen, play that never became pause, the app losing its pane to
any app with a live session, audio playing "as if it were not the app".
One shrunk file, four symptoms, since 31 July (2540556).
Two protections, because they fail differently:
- res/raw/keep.xml with tools:keep is the official mechanism for
dynamically resolved resources and is what actually binds the shrinker;
- RecursosResueltosPorNombre.kt gives them genuine R.drawable references,
the same thing that kept ic_stat_pluriwave alive all along.
station_art_* are kept too. They are reached the same way, through
android.resource:// URIs built in Dart, and survived only by luck.
Tests: 1165, unchanged -- this is a build-configuration fix, and no Dart
test can see it. The CI resource guard is what verifies it now.
FreeTLab
c3cc4120c0