Fix requiresVisibilityOf in the Gradle plugin (KT-34312)

* Fix adding new items (which was untested, as the logic was only tested
 by unit tests)

* Exclude the source set's dependsOn transitive closure from the
requiresVisibilityOf checks (i.e. these source sets are considered
visible)

* Fix minor issues in the `UnsatisfiedSourceSetVisibilityException`
message

* Add `requiresVisibilityOf` to integration tests

Issue #KT-34312 Fixed

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

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.gradle.plugin.mpp.NativeOutputKind
 import org.jetbrains.kotlin.gradle.plugin.mpp.UnusedSourceSetsChecker
 import org.jetbrains.kotlin.gradle.plugin.sources.METADATA_CONFIGURATION_NAME_SUFFIX
 import org.jetbrains.kotlin.gradle.plugin.sources.SourceSetConsistencyChecks
+import org.jetbrains.kotlin.gradle.plugin.sources.UnsatisfiedSourceSetVisibilityException
 import org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget
 import org.jetbrains.kotlin.gradle.util.*
 import org.jetbrains.kotlin.konan.target.CompilerOutputKind
@@ -2104,6 +2105,14 @@ class NewMultiplatformIT : BaseGradleIT() {
             // Native:
             assertFileExists("build/classes/kotlin/$nativeHostTargetName/integrationTest/integrationTest.klib")
         }
+
+        gradleBuildScript().appendText(
+            "\nkotlin.sourceSets { getByName(\"commonTest\").requiresVisibilityOf(getByName(\"commonIntegrationTest\")) }"
+        )
+        build {
+            assertFailed()
+            assertContains(UnsatisfiedSourceSetVisibilityException::class.java.simpleName)
+        }
     }
 
     @Test

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/new-mpp-associate-compilations/build.gradle

@@ -22,7 +22,10 @@ kotlin {
             }
         }
 
-        create("commonIntegrationTest")
+        create("commonIntegrationTest") {
+            requiresVisibilityOf(getByName("commonMain"))
+            requiresVisibilityOf(getByName("commonTest"))
+        }
     }
 
     jvm {
@@ -51,6 +54,9 @@ kotlin {
         compilations.create("integrationTest") {
             associateWith(compilations["test"])
             defaultSourceSet.dependsOn(sourceSets["commonIntegrationTest"])
+            defaultSourceSet.requiresVisibilityOf(sourceSets["commonMain"])
+            defaultSourceSet.requiresVisibilityOf(sourceSets["commonTest"])
+            defaultSourceSet.requiresVisibilityOf(sourceSets["commonIntegrationTest"])
         }
     }
 }

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

@@ -124,7 +124,7 @@ class DefaultKotlinSourceSet(
         get() = Collections.unmodifiableSet(_requiresVisibilityOf)
 
     override fun requiresVisibilityOf(other: KotlinSourceSet) {
-        requiresVisibilityOf += other
+        _requiresVisibilityOf += other
     }
 
     //region IDE import for Granular source sets metadata

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

@@ -66,7 +66,7 @@ class UnsatisfiedSourceSetVisibilityException(
             append(
                 "The source set ${sourceSet.name} requires visibility of the " +
                         singularOrPlural(requiredButNotVisible, "source set", "source sets:") + " " +
-                        "${requiredButNotVisible.joinToString()}. " +
+                        "${requiredButNotVisible.joinToString { it.name }}. " +
                         "This requirement was not satisfied.\n\n"
             )
 
@@ -90,7 +90,7 @@ class UnsatisfiedSourceSetVisibilityException(
 
                 append(
                     if (isAssociatedCompilation)
-                        ", which compiles" +
+                        ", which compiles " +
                                 singularOrPlural(allKotlinSourceSets, "source set ", "source sets: ") +
                                 allKotlinSourceSets.joinToString { it.name } +
                                 "\n"
@@ -109,9 +109,9 @@ class UnsatisfiedSourceSetVisibilityException(
                     } else {
                         append(
                             "${indent}To ensure the required visibility, the compilation " + compilationWithTarget(compilation) +
-                                    "must have a direct or indirect associate that compiles the source " +
+                                    " must have a direct or indirect associate that compiles the source " +
                                     singularOrPlural(missingRequiredSourceSets, "set ", "sets: ") +
-                                    missingRequiredSourceSets.joinToString() + "\n"
+                                    missingRequiredSourceSets.joinToString { it.name } + "\n"
                         )
                     }
                 }
@@ -140,7 +140,7 @@ internal fun checkSourceSetVisibilityRequirements(
         val inferredVisibility =
             getVisibleSourceSetsFromAssociateCompilations(compilationsBySourceSet[sourceSet].orEmpty())
 
-        val requiredButNotVisible = requiredVisibility - inferredVisibility //TODO minus dependsOn?
+        val requiredButNotVisible = requiredVisibility - inferredVisibility - sourceSet.getSourceSetHierarchy()
 
         if (requiredButNotVisible.isNotEmpty()) {
             val compilations = compilationsBySourceSet.getValue(sourceSet)