[Gradle] Report warning when targets are not distinguishable

^KT-55751 Verification Pending

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/mpp/MppDiagnosticsIt.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.gradle.mpp
 
 import org.gradle.util.GradleVersion
 import org.jetbrains.kotlin.gradle.testbase.*
+import org.jetbrains.kotlin.gradle.util.replaceText
 import kotlin.io.path.appendText
 import kotlin.io.path.writeText
 import kotlin.test.assertFalse
@@ -50,6 +51,45 @@ class MppDiagnosticsIt : KGPBaseTest() {
         }
     }
 
+    @GradleTest
+    fun testReportTargetsOfTheSamplePlatformAndWithTheSameAttributes(gradleVersion: GradleVersion) {
+        project("new-mpp-lib-and-app/sample-lib-gradle-kotlin-dsl", gradleVersion) {
+            // A hack to make project compatible with GradleTestKit infrastructure
+            buildGradleKts.replaceText(
+                """id("org.jetbrains.kotlin.multiplatform").version("<pluginMarkerVersion>")""",
+                """id("org.jetbrains.kotlin.multiplatform")""",
+            )
+            buildGradleKts.appendText("""
+                
+                val distinguishAttribute = Attribute.of(String::class.java) 
+                fun org.jetbrains.kotlin.gradle.plugin.KotlinTarget.applyDistinguishingAttributeIfSet(value: String) {
+                    if (project.properties.containsKey("applyDistinguishingAttribute")) {
+                        attributes { 
+                            attribute(distinguishAttribute, value)
+                        }
+                    }
+                }
+                kotlin {
+                    jvm("jvm2") { applyDistinguishingAttributeIfSet("jvm2") }
+                    linuxArm64("linuxArm_A") { applyDistinguishingAttributeIfSet("linuxArm_A") }
+                    linuxArm64("linuxArm_B") { applyDistinguishingAttributeIfSet("linuxArm_B") }
+                }
+            """.trimIndent())
+
+            val warningMessage = """w: The following targets are not distinguishable:
+                    |  * 'jvm2', 'jvm6'
+                    |  * 'linuxArm_A', 'linuxArm_B'""".trimMargin()
+
+            build {
+                assertOutputContains(warningMessage)
+            }
+
+            build(buildOptions = defaultBuildOptions.copy(freeArgs = listOf("-PapplyDistinguishingAttribute"))) {
+                assertOutputDoesNotContain(warningMessage)
+            }
+        }
+    }
+
     private fun TestProject.checkDeprecatedProperties(isDeprecationExpected: Boolean) {
         build {
             val assert: (Boolean, String) -> Unit = if (isDeprecationExpected) ::assertTrue else ::assertFalse

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/internal/deprecationDiagnostics.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.gradle.plugin.mpp.internal
 
 import org.gradle.api.Project
 import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
+import org.jetbrains.kotlin.gradle.dsl.multiplatformExtension
 import org.jetbrains.kotlin.gradle.dsl.multiplatformExtensionOrNull
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet.Companion.COMMON_MAIN_SOURCE_SET_NAME
 import org.jetbrains.kotlin.gradle.plugin.PropertiesProvider.Companion.kotlinPropertiesProvider
@@ -19,6 +20,7 @@ import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
 import org.jetbrains.kotlin.gradle.plugin.sources.internal
 import org.jetbrains.kotlin.gradle.utils.SingleWarningPerBuild
 import org.jetbrains.kotlin.gradle.utils.runProjectConfigurationHealthCheckWhenEvaluated
+import org.jetbrains.kotlin.gradle.utils.toMap
 import org.jetbrains.kotlin.konan.target.KonanTarget
 import org.jetbrains.kotlin.tooling.core.UnsafeApi
 
@@ -28,6 +30,7 @@ internal fun runDeprecationDiagnostics(project: Project) {
     checkAndReportDeprecatedSourceSetsLayouts(project)
     project.runProjectConfigurationHealthCheckWhenEvaluated {
         checkAndReportDeprecatedNativeTargets(project)
+        reportTargetsWithNonUniqueConsumableConfigurations(project)
     }
 }
 
@@ -41,6 +44,35 @@ private fun checkAndReportDeprecatedNativeTargets(project: Project) {
     )
 }
 
+/**
+ * Report scenario when there are two targets of the same platform without distinguishing attribute
+ */
+private fun reportTargetsWithNonUniqueConsumableConfigurations(project: Project) {
+    // Wrap diagnostic check again to afterEvaluate to make sure that it gets executed the last
+    // Since Multiplatform plugin updates consumable configurations in afterEvaluate blocks
+    project.afterEvaluate {
+        val allTargets = project.multiplatformExtension.targets
+
+        val nonDistinguishableTargets = allTargets
+            .groupBy { target -> project.configurations.getByName(target.apiElementsConfigurationName).attributes.toMap() }
+            .values
+            .filter { targetGroup -> targetGroup.size > 1 }
+
+        if (nonDistinguishableTargets.isEmpty()) return@afterEvaluate
+
+        val nonUniqueTargetsString = nonDistinguishableTargets.joinToString(separator = "\n") { targets ->
+            val targetsListString = targets.joinToString { "'${it.name}'" }
+            "  * $targetsListString"
+        }
+
+        SingleWarningPerBuild.show(
+            project,"w: The following targets are not distinguishable:\n$nonUniqueTargetsString" +
+            "\nUse distinguish attribute. " +
+            "See https://kotlinlang.org/docs/multiplatform-set-up-targets.html#distinguish-several-targets-for-one-platform for more details."
+        )
+    }
+}
+
 /**
  * Declared properties have to be captured during plugin application phase before the HMPP migration util sets them.
  * Warnings have to be reported only for successfully evaluated projects without errors.

libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/utils/gradleAttributesContainerUtils.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.utils
+
+import org.gradle.api.attributes.Attribute
+import org.gradle.api.attributes.AttributeContainer
+
+/**
+ * KGP's internal analog of [org.gradle.api.internal.attributes.AttributeContainerInternal.asMap]
+ * Can be used to compare attributes
+ */
+internal fun AttributeContainer.toMap(): Map<Attribute<*>, Any?> {
+    val result = mutableMapOf<Attribute<*>, Any?>()
+    for (key in keySet()) {
+        result[key] = getAttribute(key)
+    }
+
+    return result
+}