chore: enable R8 optimised resource shrinking and guard it - #183
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Investigation finding: R8 code + resource shrinking is already enabled by Flutter's Gradle plugin default. Spec covers the remaining cleanup and opt-ins: drop the dead android.enableR8 flag, add android.r8.optimizedShrinking, and assert release stays R8-optimised so the implicit default can't silently regress. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Android Studio prompted to "enable app optimization with R8". R8 code +
resource shrinking is already on (Flutter's Gradle plugin enables it for
release by default), so this covers the remaining gaps rather than a first
enablement:
- drop android.enableR8=true — AGP has had it Enforced since 7.0 and warns
to delete it; it misleads readers about where the real switch lives
- add android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised
resource shrinking; prerequisites already default on
- assert release stays minifyEnabled + shrinkResources so the implicit
Flutter default can't silently regress via -Pshrink=false or an upstream
change
Verified: phone/wear/auto release builds all shrink (-719K/-670K/-478K B),
-Pshrink=false now fails fast with the assertion, and the phone release APK
renders cleanly on the Pixel 7a emulator (no missing shrunk resources).
The IDE quick-fix inserts the AGP 9.3+ optimization{enable=true} DSL, which
does not exist on our AGP 8.11.1 and fails to configure; this uses the
correct 8.11 path.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Summary
android.enableR8=trueflag fromgradle.properties(AGP has had itEnforcedsince 7.0 and warns to delete it).android.r8.optimizedShrinking=true— AGP 8.11's name for R8 optimised resource shrinking (prerequisitesintegratedResourceShrinking+nonFinalResIdsalready default true).app/build.gradlethat thereleasebuild type staysminifyEnabled+shrinkResources, so the implicit Flutter default can't silently regress.Why
Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for
releaseby default (minify{Phone,Auto,Wear}ReleaseWithR8all run;mapping.txtshows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.The IDE quick-fix for that prompt inserts the AGP 9.3+
optimization { enable = true }DSL, which does not exist on our AGP 8.11.1 (Optimizationhas noenableproperty until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.Design spec:
docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.Note: R8 only optimises the Java/Kotlin layer; the Dart code in
libapp.sois untouched (--obfuscateis a separate, out-of-scope lever).Test plan
flutter build appbundle --flavor phone --releasebuilds clean (assertion passes, R8 runs)flutter build appbundle --flavor wear --release -t lib/main_wear.dartbuilds cleanflutter build apk --flavor auto --release -t lib/main.dartbuilds cleanphonerelease APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)-Pshrink=falsenow fails with the R8-optimised assertion (guard works)