play-billing-library-version-upgrade

name	play-billing-library-version-upgrade
description	Use this skill when upgrading or migrating an Android project from any legacy Google Play Billing Library (PBL) version to the latest stable version of PBL.
license	Complete terms in LICENSE.txt
metadata	{"author":"Google LLC","last-updated":"2026-09-01","keywords":["android","play billing","play billing library","pbl","upgrade","migration","deprecation","google play"]}

Phase 0: Intent Message

Reporting Action: Before proceeding, immediately tell the user: "I will upgrade Play Billing Library to the latest version."

Phase 1: Discovery & Situational Awareness

1. Primary Check (Build Version) : Locate the project's billing dependency (e.g., com.android.billingclient:billing) in build.gradle, build.gradle.kts, or libs.versions.toml.
2. Initial Compilation Test: Attempt to sync and build the project immediately.
3. Fallback Discovery (Effective Version) :
   • Trigger: Only if the build fails immediately, scan the source code for deprecated artifacts.
   • Logic : The presence of deprecated APIs indicates the "Effective Version" ---defined as the version where those specific APIs were last available, not when they were introduced.
   • Example : If SkuDetails is present, treat the baseline as PBL v7 or earlier (regardless of the version string in build.gradle).
4. Identify Target & Path : Access the version tool or release notes to find the latest stable version and calculate a [Direct/Stepped] migration path based on the Effective Version baseline.

• Calculate Migration Path :
  • If the Effective Version is within 2 major versions of the target: Plan a Direct Migration.
  • If it is more than 2 major versions behind: Plan a Stepped Migration. Migrate by two major versions at a time (e.g., v4 -> v6 -> v8) until you are within two versions of the target.
• Reporting Action: Before proceeding, tell the user: "I've detected you are effectively on PBL [Current] and the latest is [Target]. I am planning a [direct/stepped] migration path."

Phase 2: Contextual Document Mapping & Planning

For every major version jump identified in your path, you MUST synthesize instructions from:

• Migration Guide (where [X] is the target major version).
• Release Highlights : The "Deprecations" and "Breaking Changes" sections of the relevant Release Notes.
• Developer Documentation: Consult your knowledge of the Google Play Billing documentation regarding the relevant features used in this app (e.g., Subscriptions, One-Time Products).
• Develop the Plan: Identify every specific code change required (API removals, class replacements, logic shifts) and print this out as a checklist.

Phase 3: Instructions for Execution

Reporting Action: For each of the following steps, give a brief explanation of what you will be doing prior to execution, and a brief summary of what you accomplished afterwards.

Step 1: SDK & Environment Alignment

• Action : Update build.gradle to meet SDK requirements (e.g., "PBL 9 requires compileSdk 35").
• Gradle Version: Verify if the new library requires a newer Android Gradle Plugin (AGP) or Kotlin version.

Step 2: Intent-based Refactoring

Analyze the intent of the existing code rather than performing purely textual string replacement.

• Action : You MUST follow all deprecation instructions and refactor patterns from both the references/migration-logic.md section, the official migration guides, and the general documentation pages identified in Phase 2.
• Verification : Verify you are doing all steps from all documentation and then making sure you follow the specific directions from the checklist in the references.

Step 3: Sequential Verification (Only applicable for Stepped Migrations)

1. Upgrade to the first major intermediate version in your path.
2. Run ./gradlew assembleDebug to verify no intermediate breaking changes were missed.
3. Repeat until you reach the final target version.

Step 4: Final Validation Checklist

1. Smart Checklist Verification:
2. Open references/version-checklist.md and locate the Smart Version-Specific Checklist.
3. Action: For every version between your [Detected Effective Version] and [Detected New Version], verify that every item has been addressed in the code using "Find in Files" or structural analysis.
4. Tests : Run all unit and implementation tests (./gradlew test).
5. Clean Build : Verify the project completes a full clean build: ./gradlew clean assembleDebug. Then, run ./gradlew sync and ./gradlew build so that the user can immediately test the new version manually.

Final Report

Explain the "Why" to the developer:

• "I updated your SDK to [Version] because PBL [Version] requires it for [Reason from docs]."
• "I removed your custom retryConnection() logic because it is now handled natively by the library using enableAutoServiceReconnection()."
• "Successfully upgraded from PBL [Old] to PBL [New] and verified with unit tests. Based on an analysis of features in the latest library and this application's current feature set, I suggest exploring [New Feature] (e.g., Prepaid Plans or Installments) from the latest release because it is now available but not yet implemented."