fix(google): avoid r8 billing reflection

[hyochan]

Summary

• replace reflection-based SubscriptionProductReplacementParams construction with typed Play Billing 9.1 API calls
• add direct native-builder coverage for every subscription replacement mode
• remove obsolete class-path reflection tests for this now-statically-linked API

Why

Minified Android release apps could have Billing classes or methods optimized in ways the name-based reflection path could not follow. Using typed calls lets R8 trace and rewrite those references without requiring a package-wide Billing keep rule. The change is isolated to the Play source set; Horizon and Amazon do not compile this code.

Verification

• :openiap:test
• Play, Horizon, and Amazon debug Kotlin compilation
• Play, Horizon, and Amazon release AAR assembly
• :openiap:lintPlayRelease
• Kotlin 2.1 Play, Horizon, and Amazon consumer verification
• bun audit:parity
• minified Play :Example:assemblePlayRelease with R8; confirmed the merged configuration contains no broad -keep class com.android.billingclient.api.** { *; } workaround

A live Google Play Sandbox replacement purchase was not performed because it requires an active subscription and store-authorized test account. Reporter validation of the resulting snapshot is still recommended for the final store-backed runtime check.

Closes #307

Summary by CodeRabbit

• Bug Fixes

  • Improved subscription replacement handling by using the supported Google Play Billing conversion, helping replacement requests work reliably with current billing APIs.
  • Removed outdated compatibility logic that could cause errors during subscription changes.

• Tests

  • Added coverage confirming all supported replacement modes produce the expected billing parameters.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: d1950140-a05f-4bcc-9fc7-c2c5d2c5f388

📥 Commits

Reviewing files that changed from the base of the PR and between 1ede6c5 and 742d075.

📒 Files selected for processing (4)

• packages/google/openiap/src/play/java/dev/hyo/openiap/OpenIapModule.kt
• packages/google/openiap/src/play/java/dev/hyo/openiap/SubscriptionReplacementModeAndroidExt.kt
• packages/google/openiap/src/test/java/dev/hyo/openiap/BillingLibraryClassPathTest.kt
• packages/google/openiap/src/testPlay/java/dev/hyo/openiap/SubscriptionReplacementModeTest.kt

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📝 Walkthrough

Walkthrough

The Android subscription replacement flow now uses typed Billing Library builders instead of reflection. Tests cover native parameter conversion for all replacement modes, and obsolete reflection-based class-path tests are removed.

Changes

Subscription replacement conversion

Layer / File(s)	Summary
Native replacement parameter conversion packages/google/openiap/src/play/java/dev/hyo/openiap/SubscriptionReplacementModeAndroidExt.kt, packages/google/openiap/src/play/java/dev/hyo/openiap/OpenIapModule.kt	The module applies typed Billing Library replacement parameters. The conversion sets the old product ID and native replacement mode.
Conversion test updates packages/google/openiap/src/testPlay/java/dev/hyo/openiap/SubscriptionReplacementModeTest.kt, packages/google/openiap/src/test/java/dev/hyo/openiap/BillingLibraryClassPathTest.kt	Play tests cover every replacement mode. Obsolete reflection-based class-path tests and their unused helper are removed.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• hyodotdev/openiap#52: This PR refines the earlier subscription replacement implementation in OpenIapModule.kt.
• hyodotdev/openiap#72: Both PRs update replacement-mode mapping from reflection-based handling to native Billing Library APIs.
• hyodotdev/openiap#96: Both PRs update SubscriptionReplacementModeAndroidExt.kt and its tests.

Suggested labels: ፦ refactor, 🧪 test

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: replacing Billing reflection to avoid R8 failures in Google Play builds.
Linked Issues check	✅ Passed	The changes replace reflective Billing calls with typed APIs and add coverage, directly addressing the release-only subscription replacement failure in issue #307.
Out of Scope Changes check	✅ Passed	The changes are limited to the Play implementation and related tests, with no unrelated code or platform changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/google-r8-subscription-replacement

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