Set LV for KMP manually because of the stdlib problems

Author: Mr3zee

gradle-conventions/src/main/kotlin/conventions-kmp.gradle.kts

@@ -42,4 +42,3 @@ withKmpConfig {
 configureJvm(isKmp = true)
 
 configureJavaCompatibility(8)
-configureKotlinCompatibility("2.0.0")

gradle-conventions/src/main/kotlin/conventions-kotlin-version.gradle.kts

@@ -2,7 +2,10 @@
  * Copyright 2023-2025 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
  */
 
+import org.jetbrains.kotlin.gradle.dsl.KotlinCommonCompilerOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinProjectExtension
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
+import util.other.libs
 import util.withKotlinJvmExtension
 import util.withKotlinKmpExtension
 
@@ -13,10 +16,26 @@ fun KotlinProjectExtension.optInForRpcApi() {
     }
 }
 
+/**
+ * Set the compatibility mode to the lower supported language version.
+ *
+ * This should be lined up with the minimal supported compiler plugin version.
+ *
+ * We update the language version only for the 'main' sources sets.
+ * This makes our tests execute against the latest compiler plugin version (for example, with K2 instead of K1).
+ */
+fun KotlinCommonCompilerOptions.setProjectLanguageVersion() {
+    languageVersion.set(KotlinVersion.KOTLIN_2_0)
+    apiVersion.set(KotlinVersion.KOTLIN_2_0)
+}
+
 withKotlinJvmExtension {
     optInForRpcApi()
 }
 
 withKotlinKmpExtension {
     optInForRpcApi()
+
+    // We don't use `compat-patrouille` here because it sets stdlib version, and that breaks WASM tests.
+    compilerOptions.setProjectLanguageVersion()
 }