r8-proguard-optimization

name	r8-proguard-optimization
description	Use for Android release shrinking, R8 and ProGuard keep rules, minify release failures, resource shrinking and Crashlytics mapping uploads.

Purpose

Fix release-only failures and optimize shrinking without disabling R8 or adding broad unsafe keep rules.

When to use

• App fails only in release builds.
• minifyEnabled or shrinkResources causes crashes.
• Retrofit, serialization, Hilt, Room or Firebase needs targeted keep rules.
• Crashlytics mapping upload must be configured.

Inputs to inspect

• app/build.gradle.kts release build type
• proguard-rules.pro and consumer-rules.pro
• Reflection, serialization and Retrofit converters
• Room entities and Hilt modules
• Firebase and Crashlytics Gradle setup

Required workflow

1. Reproduce using release or minified build.
2. Read R8 error output and mapping context.
3. Add the narrowest keep rule possible.
4. Verify release tests or smoke tests.
5. Document mapping file handling for Crashlytics.

Rules

• Do not disable R8 as a permanent fix.
• Do not add -keep class ** { *; } except as a temporary diagnostic.
• Prefer library-documented rules and narrow app rules.
• Validate release behavior, not only debug.
• Preserve obfuscation unless debugging requires a temporary change.

Related existing skills

Local skills to invoke

• gradle-build
• play-store-release
• debugging
• firebase-crashlytics-analytics

External companion skills to use when installed

Do not assume these companion skills are installed. Prefer the local skills above first, then consult Companion Skills for install and verification commands.

• android/skills — use for official Android workflow alignment around edge-to-edge, adaptive UI, Navigation 3, R8, AGP or testing setup.

Files commonly touched

• app/build.gradle.kts
• proguard-rules.pro
• consumer-rules.pro
• crashlytics Gradle config
• Serialization models
• Network and DI setup

Commands to validate

./gradlew assembleRelease
./gradlew app:minifyReleaseWithR8
./gradlew testReleaseUnitTest

Common mistakes to avoid

• Testing only debug after changing R8 rules.
• Adding global keep rules that erase shrinking benefits.
• Forgetting mapping upload for crash reports.
• Ignoring consumer rules in library modules.

Checklist

• Release failure reproduced.
• Specific rule added.
• Release build validated.
• Mapping behavior documented.
• Residual obfuscation risk mentioned.

Example prompts

• Use $super-android-kotlin-firebase to fix this release-only R8 crash.
• Use $super-android-kotlin-firebase to review my ProGuard rules before release.

Expected response style

Respond with: brief diagnosis, change plan, affected files, code or diff summary, validation commands, tests added or recommended, risks, and next step. For review tasks, lead with findings ordered by severity.

References

• ../../docs/audits/FUENTES_LOCALES.md
• references/r8-release-checklist.md
• references/common-keep-rules.md
• references/firebase-r8-notes.md
• references/reflection-serialization-rules.md
• templates/proguard-rules-template.pro
• templates/release-buildtype-template.md
• templates/crashlytics-mapping-upload-template.md