[EXTERNAL] Fix build on AGP 9 by skipping kotlin-android when AGP registers the kotlin extension (#1934) via @gabrieldonadel - #1939
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…in extension (#1934) ## Problem Android Gradle Plugin 9 ships built-in Kotlin support and enables it by default, so AGP registers the `kotlin` extension itself. When a library *also* applies `kotlin-android` explicitly, the two collide and configuration fails before anything compiles: ``` > Failed to apply plugin 'kotlin-android'. > Cannot add extension with name 'kotlin', as there is an extension already registered with that name. ``` The apply is unconditional in both files, so on an AGP 9 project this library cannot be built at all. There is no consumer-side workaround short of patching the file — setting `android.builtInKotlin=false` project-wide just to build one dependency is not a reasonable ask, and that escape hatch is removed in AGP 10. ## Change Apply the plugin only when nothing has registered the `kotlin` extension yet: ```groovy if (project.extensions.findByName('kotlin') == null) { apply plugin: 'kotlin-android' } ``` Files changed: - `android/build.gradle` - `react-native-purchases-ui/android/build.gradle` This checks the exact condition that fails, so there is no AGP version table to keep in sync. It follows the approach already used in [purchases-capacitor#860](RevenueCat/purchases-capacitor#860) and [purchases-flutter#1765](RevenueCat/purchases-flutter#1765), per maintainer review on this PR. Behaviour across configurations: | AGP | `android.builtInKotlin` | `kotlin` extension | explicit apply | |---|---|---|---| | 8.x | unset or `false` | absent | yes (unchanged) | | 9.x | unset or `true` | registered by AGP | no | | 9.x | `false` | absent | yes | | 10+ | n/a (opt-out removed) | registered by AGP | no | The check sits after `apply plugin: 'com.android.library'` in both files, so AGP has already registered its extensions by the time it runs. ## What I verified, and what I did not - **Verified end to end** on a real Expo SDK 58 / React Native 0.87 project with AGP 9.2.1 and Gradle 9.4.1: `:app:assembleDebug` succeeds both with `-Pandroid.newDsl=true -Pandroid.builtInKotlin=true` and with both flags off. - Confirmed both branches actually execute, rather than one path silently always being taken: with the flags off, `:<module>:compileDebugKotlin` runs from the explicitly applied plugin; with them on, the build succeeds without it, which it could not do if the plugin were still being applied. - Syntax-checked both files with Groovy's `Phases.CONVERSION`. - **Not run:** this repo's own CI or example app. You mentioned you'd handle AGP 9 CI coverage separately. Found while sweeping 157 popular React Native libraries for AGP 9 new-DSL compatibility. 34 failed with the new DSL enabled, and 29 of those failed on exactly this — it is the most common blocker by a wide margin.
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External contribution from @gabrieldonadel, merged into this branch to run CI. Original PR: #1934
Note
Low Risk
Gradle plugin wiring only; no runtime or security impact, with behavior unchanged on pre-AGP-9 toolchains.
Overview
Fixes Android Gradle Plugin 9 builds that fail with "Cannot add extension with name 'kotlin'" when both AGP’s built-in Kotlin support and the
kotlin-androidplugin run together.In
android/build.gradleandreact-native-purchases-ui/android/build.gradle,kotlin-androidis no longer applied unconditionally. It is applied only whenproject.extensions.findByName('kotlin')is null, so older AGP setups still get the plugin while AGP 9 can rely on its ownkotlinextension.Reviewed by Cursor Bugbot for commit 22131fc. Bugbot is set up for automated code reviews on this repo. Configure here.