[Gradle] Add KotlinCompilationSourceDeprecation diagnostic

^KT-58235 Verification Pending

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/diagnostics/KotlinToolingDiagnostics.kt

@@ -548,6 +548,18 @@ object KotlinToolingDiagnostics {
             """.trimIndent()
         )
     }
+
+    object KotlinCompilationSourceDeprecation : ToolingDiagnosticFactory(ERROR) {
+        operator fun invoke(trace: Throwable?) = build(
+            """
+                `KotlinCompilation.source(KotlinSourceSet)` method is deprecated 
+                and will be removed in upcoming Kotlin releases.
+
+                See https://kotl.in/compilation-source-deprecation for details.
+            """.trimIndent(),
+            throwable = trace,
+        )
+    }
 }
 
 private fun String.indentLines(nSpaces: Int = 4, skipFirstLine: Boolean = true): String {

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/compilationImpl/KotlinCompilationImpl.kt

@@ -15,6 +15,8 @@ import org.gradle.api.tasks.TaskProvider
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinCompile
 import org.jetbrains.kotlin.gradle.plugin.*
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.KotlinToolingDiagnostics.KotlinCompilationSourceDeprecation
+import org.jetbrains.kotlin.gradle.plugin.diagnostics.kotlinToolingDiagnosticsCollector
 import org.jetbrains.kotlin.gradle.plugin.mpp.HierarchyAttributeContainer
 import org.jetbrains.kotlin.gradle.plugin.mpp.InternalKotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.mpp.internal
@@ -91,6 +93,7 @@ internal class KotlinCompilationImpl constructor(
 
     @Deprecated("scheduled for removal with Kotlin 2.0", level = DeprecationLevel.ERROR)
     override fun source(sourceSet: KotlinSourceSet) {
+        project.kotlinToolingDiagnosticsCollector.report(project, KotlinCompilationSourceDeprecation(Throwable()))
         sourceSets.source(sourceSet)
     }
 

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/unitTests/diagnosticsTests/MppDiagnosticsFunctionalTest.kt

@@ -106,4 +106,15 @@ class MppDiagnosticsFunctionalTest {
             kotlin { }
         }
     }
+
+    @Test
+    fun testKotlinCompilationSourceDeprecation() {
+        checkDiagnosticsWithMppProject("kotlinCompilationSourceDeprecation") {
+            kotlin {
+                val customMain = sourceSets.create("customMain")
+                @Suppress("DEPRECATION_ERROR")
+                jvm().compilations.create("custom").source(customMain)
+            }
+        }
+    }
 }

libraries/tools/kotlin-gradle-plugin/src/functionalTest/resources/expectedDiagnostics/kotlinCompilationSourceDeprecation.txt

@@ -0,0 +1,4 @@
+[KotlinCompilationSourceDeprecation | ERROR] `KotlinCompilation.source(KotlinSourceSet)` method is deprecated
+and will be removed in upcoming Kotlin releases.
+
+See https://kotl.in/compilation-source-deprecation for details.