fix(android): skip explicit Kotlin plugin when AGP registers the kotlin extension

[gabrieldonadel]

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. AGP
words it two ways, both the same problem:

> Failed to apply plugin 'kotlin-android'.
   > Cannot add extension with name 'kotlin', as there is an extension already registered with that name.

> The 'kotlin-android' plugin is no longer required for Kotlin support since AGP 9.0.

The apply is unconditional in all 4 modules below, so on an AGP 9 project this 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:

if (project.extensions.findByName('kotlin') == null) {
    apply plugin: 'kotlin-android'
}

Files changed:

• packages/noise-cancellation-react-native/android/build.gradle
• packages/react-native-callingx/android/build.gradle
• packages/react-native-sdk/android/build.gradle
• packages/video-filters-react-native/android/build.gradle

This tests the condition that actually fails, so there is no AGP version table to
keep in sync, and it covers AGP 10 — where the android.builtInKotlin opt-out is
removed — without a special case.

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 (removed)	registered by AGP	no

The guard sits after apply plugin: 'com.android.library' in every file it touches,
so AGP has already registered its extensions by the time it runs. I checked that
ordering per file rather than assuming it.

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 always winning: with
  the flags off, compileDebugKotlin runs from the explicitly applied plugin; with
  them on the build completes without it.
• Every changed file passes a Groovy Phases.CONVERSION syntax check.
• Not run: this repo's own CI or example app.

Where this came from

A sweep of 1000 popular React Native libraries against the AGP 9 defaults. 281 failed
with the new DSL enabled, and 269 of those failed on exactly this collision — by
far the most common blocker. Affects @stream-io/react-native-callingx, @stream-io/video-react-native-sdk here.

The same guard shape was accepted in
RevenueCat/react-native-purchases#1934,
at that maintainer's suggestion.

Summary by CodeRabbit

• Bug Fixes
  • Resolved Android build configuration failures when using Android Gradle Plugin 9.
  • Improved compatibility across the affected React Native packages by avoiding duplicate Kotlin configuration.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: e93cbae6-b9cf-4d60-ab1f-4cef6982c606

📥 Commits

Reviewing files that changed from the base of the PR and between 8554686 and cc4a9d2.

📒 Files selected for processing (4)

• packages/noise-cancellation-react-native/android/build.gradle
• packages/react-native-callingx/android/build.gradle
• packages/react-native-sdk/android/build.gradle
• packages/video-filters-react-native/android/build.gradle

Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review.

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📝 Walkthrough

Walkthrough

The Android build scripts conditionally apply kotlin-android only when the kotlin extension is absent. This avoids extension-name conflicts with AGP 9 built-in Kotlin support across four React Native packages.

Changes

Android build compatibility

Layer / File(s)	Summary
Conditional Kotlin plugin application packages/noise-cancellation-react-native/android/build.gradle, packages/react-native-callingx/android/build.gradle, packages/react-native-sdk/android/build.gradle, packages/video-filters-react-native/android/build.gradle	Each build script checks for an existing kotlin extension before applying kotlin-android.

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

Merge Risk: ⚪ Minimal · up to cc4a9

Android library builds now avoid applying kotlin-android when AGP already provides Kotlin support, while preserving the prior behavior for configurations without that extension. No current merge-blocking risk remains.

Suggested reviewers: santhoshvai

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: skipping the explicit Kotlin plugin when AGP registers the kotlin extension.
Description check	✅ Passed	The description is detailed, relevant, and covers the problem, implementation, affected files, compatibility behavior, and verification results. It does not use the template headings and does not prov…
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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