From 1c97e44092e0b3f151216066c01a8a3ebcc8f52f Mon Sep 17 00:00:00 2001
From: Gabriel Donadel Dall'Agnol <donadeldev@gmail.com>
Date: Wed, 2 Sep 2026 14:03:34 -0700
Subject: [PATCH 1/2] fix(android): skip explicit Kotlin plugin when AGP
 provides built-in Kotlin

AGP 9 enables built-in Kotlin by default and applies the Kotlin plugin
itself. Applying it again fails configuration with "Cannot add extension
with name 'kotlin'". Guard the explicit apply so it only runs when AGP is
not providing Kotlin: AGP 8 and older, or AGP 9 with
android.builtInKotlin=false. AGP 10 removes that opt-out, so built-in
Kotlin is always active there and the explicit apply must never run.
---
 android/build.gradle | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/android/build.gradle b/android/build.gradle
index 41ba48c..7c0976a 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -16,7 +16,27 @@ buildscript {
 }
 
 apply plugin: 'com.android.library'
-apply plugin: 'kotlin-android'
+// Android Gradle Plugin 9 ships built-in Kotlin support and applies the Kotlin
+// plugin itself. Applying it a second time fails the configuration phase with
+// "Cannot add extension with name 'kotlin'". Apply it only when AGP is not
+// providing Kotlin: AGP 8 and older, or AGP 9 with android.builtInKotlin=false.
+def shouldApplyKotlinPlugin() {
+  def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0].toInteger()
+  if (agpMajor <= 8) {
+    return true
+  }
+  // AGP 10 removes the opt-out: built-in Kotlin is always active there.
+  if (agpMajor >= 10) {
+    return false
+  }
+  def propertyVal = providers.gradleProperty("android.builtInKotlin").orNull
+  def builtInKotlinEnabled = propertyVal != null ? propertyVal.toBoolean() : true
+  return !builtInKotlinEnabled
+}
+
+if (shouldApplyKotlinPlugin()) {
+  apply plugin: 'kotlin-android'
+}
 
 def getExtOrDefault(name) {
   return rootProject.ext.has(name) ? rootProject.ext.get(name) : project.properties['RiveReactNative_' + name]

From e814e78d29ee80cdd4243302fe8300e11da5080f Mon Sep 17 00:00:00 2001
From: Gabriel Donadel Dall'Agnol <donadeldev@gmail.com>
Date: Fri, 18 Sep 2026 03:21:44 -0700
Subject: [PATCH 2/2] fix(android): check the kotlin extension instead of the
 AGP version

Replace the AGP version / android.builtInKotlin check with a direct test for
the registered kotlin extension. The version check reads
com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION, which can resolve to a
different classpath entry than the AGP actually in use, and the global
android.builtInKotlin property can be overridden per module by the
com.android.built-in-kotlin plugin -- so both inputs can disagree with
reality. Asking whether the kotlin extension exists tests the condition that
actually fails, needs no AGP version table, and covers AGP 10 where the
opt-out is removed.
---
 android/build.gradle | 26 +++++++-------------------
 1 file changed, 7 insertions(+), 19 deletions(-)

diff --git a/android/build.gradle b/android/build.gradle
index 7c0976a..5cfb557 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -16,25 +16,13 @@ buildscript {
 }
 
 apply plugin: 'com.android.library'
-// Android Gradle Plugin 9 ships built-in Kotlin support and applies the Kotlin
-// plugin itself. Applying it a second time fails the configuration phase with
-// "Cannot add extension with name 'kotlin'". Apply it only when AGP is not
-// providing Kotlin: AGP 8 and older, or AGP 9 with android.builtInKotlin=false.
-def shouldApplyKotlinPlugin() {
-  def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0].toInteger()
-  if (agpMajor <= 8) {
-    return true
-  }
-  // AGP 10 removes the opt-out: built-in Kotlin is always active there.
-  if (agpMajor >= 10) {
-    return false
-  }
-  def propertyVal = providers.gradleProperty("android.builtInKotlin").orNull
-  def builtInKotlinEnabled = propertyVal != null ? propertyVal.toBoolean() : true
-  return !builtInKotlinEnabled
-}
-
-if (shouldApplyKotlinPlugin()) {
+// AGP 9 ships built-in Kotlin support and registers the `kotlin` extension
+// itself. Applying the Kotlin plugin on top of it fails configuration with
+// "Cannot add extension with name 'kotlin'". Asking for the extension covers
+// every way built-in Kotlin can be turned on -- the global default, the
+// android.builtInKotlin property, and the per-module com.android.built-in-kotlin
+// plugin -- without reading an AGP version number.
+if (project.extensions.findByName('kotlin') == null) {
   apply plugin: 'kotlin-android'
 }