KT-MR-5666 SourceSetMappedFragmentLocator

* fix choosing longest module name (did mistakenly choose shortest)
* fix missing return for single-part name
* add unit tests

libraries/tools/kotlin-gradle-plugin/src/functionalTest/kotlin/org/jetbrains/kotlin/gradle/sources/kpm/MultiplatformSourceSetMappedFragmentLocatorTest.kt

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+/* Associate compilations are not yet supported by the IDE. KT-34102 */
+@file:Suppress("invisible_reference", "invisible_member", "FunctionName", "DuplicatedCode")
+
+package org.jetbrains.kotlin.gradle.sources.kpm
+
+import org.jetbrains.kotlin.gradle.MultiplatformExtensionTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import org.jetbrains.kotlin.gradle.plugin.sources.kpm.MultiplatformSourceSetMappedFragmentLocator
+import org.jetbrains.kotlin.gradle.plugin.PropertiesProvider
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.KotlinGradleModule
+import org.jetbrains.kotlin.gradle.plugin.mpp.pm20.kpmModules
+import org.jetbrains.kotlin.gradle.plugin.sources.kpm.SourceSetMappedFragmentLocator
+
+internal open class MultiplatformSourceSetMappedFragmentLocatorTest : MultiplatformExtensionTest() {
+
+    protected val locator = MultiplatformSourceSetMappedFragmentLocator()
+
+    @BeforeTest
+    override fun setup() {
+        project.extensions.extraProperties.set(PropertiesProvider.PropertyNames.KOTLIN_KPM_EXPERIMENTAL_MODEL_MAPPING, "true")
+        super.setup()
+    }
+
+    protected fun doTest(sourceSetName: String, checkResult: SourceSetMappedFragmentLocator.FragmentLocation.() -> Unit) {
+        val result = checkNotNull(locator.locateFragmentForSourceSet(project, sourceSetName))
+        checkResult(result)
+    }
+
+    protected fun doTest(sourceSetName: String, fragmentName: String, moduleName: String) {
+        doTest(sourceSetName) {
+            assertEquals(fragmentName, this.fragmentName)
+            assertEquals(moduleName, this.moduleName)
+        }
+    }
+
+    @Test
+    fun `name with one part is returned as fragment name with main module`() {
+        doTest("foo", "foo", KotlinGradleModule.MAIN_MODULE_NAME)
+    }
+
+    @Test
+    fun `main is truncated from name`() {
+        doTest("fooBarMain", "fooBar", KotlinGradleModule.MAIN_MODULE_NAME)
+    }
+
+    @Test
+    fun `module chosen for test fragment`() {
+        doTest("abcDefGhiTest", "abcDefGhi", KotlinGradleModule.TEST_MODULE_NAME)
+    }
+
+    @Test
+    fun `digits accepted`() {
+        val nameWithDigits = "testDigits123Accepted123"
+        project.kpmModules.create(nameWithDigits)
+        doTest("foo${nameWithDigits.capitalize()}", "foo", nameWithDigits)
+        doTest("${nameWithDigits}Main", nameWithDigits, KotlinGradleModule.MAIN_MODULE_NAME)
+    }
+
+    @Test
+    fun `capitalized name handling`() {
+        doTest("IAmTheMain", "IAmThe", KotlinGradleModule.MAIN_MODULE_NAME)
+    }
+
+    @Test
+    fun `live module logic update`() {
+        val nameForTest = "someNewTest"
+        doTest(nameForTest, "someNew", "test")
+        project.kpmModules.create("newTest")
+        doTest(nameForTest, "some", "newTest")
+
+        // also check for the same logic in fragments that go to main if no suffix matched:
+
+        val nameForMain = "fooBarBaz"
+        doTest(nameForMain, nameForMain, KotlinGradleModule.MAIN_MODULE_NAME)
+        val moduleSuffixName = "barBaz"
+        project.kpmModules.create(moduleSuffixName)
+        doTest(nameForMain, "foo", moduleSuffixName)
+    }
+}
+
+internal class MultiplatformSourceSetMappedFragmentLocatorTestWithAndroid : MultiplatformSourceSetMappedFragmentLocatorTest() {
+
+    override fun setup() {
+        super.setup()
+        project.plugins.apply("android-library")
+        kotlin.android()
+    }
+
+    @Test
+    fun `android source set names`() {
+        doTest("androidMain", "android", KotlinGradleModule.MAIN_MODULE_NAME)
+        doTest("androidTest", "android", KotlinGradleModule.TEST_MODULE_NAME)
+        doTest("androidAndroidTest", "androidAndroid", KotlinGradleModule.TEST_MODULE_NAME)
+
+        doTest("androidDebug", "androidDebug", KotlinGradleModule.MAIN_MODULE_NAME)
+        doTest("androidDebugTest", "androidDebug", KotlinGradleModule.TEST_MODULE_NAME)
+        doTest("androidDebugAndroidTest", "androidDebugAndroid", KotlinGradleModule.TEST_MODULE_NAME)
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinProperties.kt

@@ -224,7 +224,7 @@ internal class PropertiesProvider private constructor(private val project: Proje
         get() = booleanProperty("kotlin.wasm.stability.nowarn") ?: false
 
     val experimentalKpmModelMapping: Boolean
-        get() = booleanProperty("kotlin.kpm.experimentalModelMapping") ?: false
+        get() = booleanProperty(PropertyNames.KOTLIN_KPM_EXPERIMENTAL_MODEL_MAPPING) ?: false
 
     val ignoreDisabledNativeTargets: Boolean?
         get() = booleanProperty(DisabledNativeTargetsReporter.DISABLE_WARNING_PROPERTY_NAME)
@@ -488,6 +488,7 @@ internal class PropertiesProvider private constructor(private val project: Proje
         const val KOTLIN_MPP_HIERARCHICAL_STRUCTURE_SUPPORT = "kotlin.mpp.hierarchicalStructureSupport"
         const val KOTLIN_NATIVE_DEPENDENCY_PROPAGATION = "kotlin.native.enableDependencyPropagation"
         const val KOTLIN_MPP_ENABLE_OPTIMISTIC_NUMBER_COMMONIZATION = "kotlin.mpp.enableOptimisticNumberCommonization"
+        const val KOTLIN_KPM_EXPERIMENTAL_MODEL_MAPPING = "kotlin.kpm.experimentalModelMapping"
     }
 
     companion object {

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/sources/kpm/FragmentMappedKotlinSourceSetFactory.kt

@@ -17,9 +17,8 @@ class FragmentMappedKotlinSourceSetFactory constructor(private val project: Proj
     override fun create(name: String): FragmentMappedKotlinSourceSet {
         val locator = SourceSetMappedFragmentLocator.get(project)
         val location = locator.locateFragmentForSourceSet(project, name) ?: error("Couldn't map the source set name $name to KPM fragment")
-        val (moduleName, fragmentName) = location
-        val modules = project.kpmModules
-        val fragment = modules.maybeCreate(moduleName).fragments.maybeCreate(fragmentName)
+        val fragment = project.kpmModules.maybeCreate(location.moduleName).fragments.maybeCreate(location.fragmentName)
+
         /** TODO setup JS-specific attributes similar to [org.jetbrains.kotlin.gradle.plugin.sources.DefaultKotlinSourceSetFactory]*/
         return FragmentMappedKotlinSourceSet(name, project, fragment)
     }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/sources/kpm/SourceSetMappedFragmentLocator.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.gradle.plugin.sources.kpm
 
 import org.gradle.api.Project
 import org.jetbrains.kotlin.gradle.dsl.*
-import org.jetbrains.kotlin.gradle.dsl.pm20Extension
 import org.jetbrains.kotlin.gradle.dsl.topLevelExtensionOrNull
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTargetPreset
@@ -33,11 +32,11 @@ interface SourceSetMappedFragmentLocator {
     }
 }
 
-private class MultiplatformSourceSetMappedFragmentLocator : SourceSetMappedFragmentLocator {
-    override fun locateFragmentForSourceSet(project: Project, sourceSetName: String): SourceSetMappedFragmentLocator.FragmentLocation? {
+internal class MultiplatformSourceSetMappedFragmentLocator : SourceSetMappedFragmentLocator {
+    override fun locateFragmentForSourceSet(project: Project, sourceSetName: String): SourceSetMappedFragmentLocator.FragmentLocation {
         val camelCaseParts = sourceSetName.camelCaseParts()
         if (camelCaseParts.size < 2) {
-            SourceSetMappedFragmentLocator.FragmentLocation(KotlinGradleModule.MAIN_MODULE_NAME, sourceSetName)
+            return SourceSetMappedFragmentLocator.FragmentLocation(KotlinGradleModule.MAIN_MODULE_NAME, sourceSetName)
         }
 
         val androidTarget = when (val ext = project.topLevelExtension) {
@@ -55,7 +54,7 @@ private class MultiplatformSourceSetMappedFragmentLocator : SourceSetMappedFragm
                 if (androidTarget != null && sourceSetName.startsWith(androidTarget.name))
                     androidSourceSetModuleName(androidTarget.name, sourceSetName)
                 else null
-            } ?: candidateModuleNames.firstOrNull { project.kpmModules.findByName(it) != null }
+            } ?: candidateModuleNames.lastOrNull { project.kpmModules.findByName(it) != null }
             ?: KotlinGradleModule.MAIN_MODULE_NAME
 
         val fragmentName =