From 4071894217590dc79a2fef88625d45d41fe2792d Mon Sep 17 00:00:00 2001
From: Bryan Van Deusen <bryan.vandeusen@fabledsword.com>
Date: Thu, 21 May 2026 22:57:49 -0400
Subject: [PATCH] =?UTF-8?q?fix(android):=20opt=20out=20of=20AGP=209=20buil?=
 =?UTF-8?q?t-in=20Kotlin=20=E2=80=94=20KSP=20incompatible?=
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AGP 9 enables built-in Kotlin by default (`android.builtInKotlin=true`),
which we initially adopted by dropping the `kotlin-android` plugin
alias. But KSP isn't compatible with built-in Kotlin yet — Gradle
errors out with:

  > KSP is not compatible with Android Gradle Plugin's built-in Kotlin.
  > Please disable by adding android.builtInKotlin=false to gradle.properties
  > and apply kotlin("android") plugin

Restored the explicit kotlin-android plugin (root + :app) and added
`android.builtInKotlin=false` to gradle.properties. Revisit when KSP
gains built-in-Kotlin support.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 android/app/build.gradle.kts | 8 ++++----
 android/build.gradle.kts     | 8 ++++----
 android/gradle.properties    | 6 ++++++
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/android/app/build.gradle.kts b/android/app/build.gradle.kts
index a89a5f50..5d5df87d 100644
--- a/android/app/build.gradle.kts
+++ b/android/app/build.gradle.kts
@@ -1,9 +1,9 @@
 plugins {
     alias(libs.plugins.android.application)
-    // kotlin-android removed: AGP 9.0+ auto-enables Kotlin via the
-    // android.builtInKotlin=true default. The serialization + compose-compiler
-    // plugins still need explicit application because they're language-level
-    // (Kotlin compiler) plugins beyond what built-in Kotlin provides.
+    // kotlin-android applied explicitly: AGP 9's built-in Kotlin path is
+    // not compatible with KSP yet. Opted out via
+    // android.builtInKotlin=false in gradle.properties.
+    alias(libs.plugins.kotlin.android)
     alias(libs.plugins.kotlin.serialization)
     alias(libs.plugins.compose.compiler)
     alias(libs.plugins.ksp)
diff --git a/android/build.gradle.kts b/android/build.gradle.kts
index d8425a47..b3c00232 100644
--- a/android/build.gradle.kts
+++ b/android/build.gradle.kts
@@ -1,9 +1,9 @@
 plugins {
     alias(libs.plugins.android.application) apply false
-    // kotlin-android plugin no longer needed: AGP 9.0+ auto-enables via
-    // android.builtInKotlin=true (default). Kept the serialization +
-    // compose-compiler plugins, which are language-level (Kotlin compiler)
-    // plugins still applied explicitly per module.
+    // kotlin-android needed despite AGP 9's built-in Kotlin: KSP isn't
+    // compatible with the builtInKotlin path yet, so we opt out via
+    // android.builtInKotlin=false in gradle.properties.
+    alias(libs.plugins.kotlin.android) apply false
     alias(libs.plugins.kotlin.serialization) apply false
     alias(libs.plugins.ksp) apply false
     alias(libs.plugins.hilt) apply false
diff --git a/android/gradle.properties b/android/gradle.properties
index b605a620..8e0266b4 100644
--- a/android/gradle.properties
+++ b/android/gradle.properties
@@ -4,4 +4,10 @@ org.gradle.caching=true
 org.gradle.configuration-cache=true
 android.useAndroidX=true
 android.nonTransitiveRClass=true
+
+# KSP isn't compatible with AGP 9's built-in Kotlin support (the
+# `android.builtInKotlin=true` default). Opt out so we can apply the
+# explicit kotlin-android plugin and KSP together. Revisit when KSP
+# adds built-in-Kotlin support.
+android.builtInKotlin=false
 kotlin.code.style=official