fix componentName and smartToString

mirai-core/src/commonMain/kotlin/network/component/ComponentKey.kt

@@ -9,14 +9,11 @@
 
 package net.mamoe.mirai.internal.network.component
 
-import kotlin.reflect.KClass
-import kotlin.reflect.KClassifier
-import kotlin.reflect.KType
-import kotlin.reflect.KTypeParameter
+import kotlin.reflect.*
 import kotlin.reflect.full.allSupertypes
 
 /**
- * A key for specific component [T]. Component are not polymorphic.
+ * A key for specific component [T]. Components are not polymorphic.
  *
  * @param T is a type hint.
  */
@@ -28,14 +25,36 @@ internal interface ComponentKey<T : Any> {
      * - If [qualified] is `true`, example: `net.mamoe.mirai.internal.network.components.PacketCodec`.
      */
     fun componentName(qualified: Boolean = false): String {
-        return getComponentTypeArgumentClassifier().renderClassifier(fullName = qualified)
+        val argument = getComponentTypeArgument()
+        argument?.render(qualified)?.let { return it }
+        return argument?.type?.classifier.renderClassifier(qualified)
     }
 
     fun smartToString(qualified: Boolean = false): String {
         return "ComponentKey<${componentName(qualified)}>"
     }
 
-    private companion object {
+    companion object {
+        // reflection is slow, but it is initialized once only (if memory sufficient).
+
+        private fun KTypeProjection.render(
+            fullName: Boolean
+        ): String? {
+            val projection = this
+
+            projection.type?.classifier?.let { classifier ->
+                if (classifier is KClass<*>) {
+                    return classifier.run { if (fullName) qualifiedName else simpleName } ?: "?"
+                }
+            }
+
+            projection.type?.arguments?.firstOrNull()?.let { argument ->
+                return argument.render(fullName)
+            }
+
+            return null
+        }
+
         private fun KClassifier?.renderClassifier(
             fullName: Boolean
         ): String {
@@ -53,16 +72,16 @@ internal interface ComponentKey<T : Any> {
             val upperBounds = upperBounds
             return when (upperBounds.size) {
                 0 -> toString()
-                1 -> "ComponentKey<${upperBounds[0].renderType(fullName)}>"
-                else -> "ComponentKey<${upperBounds.joinToString(" & ") { it.renderType(fullName) }}>"
+                1 -> upperBounds[0].renderType(fullName)
+                else -> upperBounds.joinToString(" & ") { it.renderType(fullName) }
             }
         }
 
-        private fun ComponentKey<*>.getComponentTypeArgumentClassifier(): KClassifier? {
+        private fun ComponentKey<*>.getComponentTypeArgument(): KTypeProjection? {
             val thisType = this::class.allSupertypes.find { it.classifier == COMPONENT_KEY_K_CLASS }
-            return thisType?.arguments?.firstOrNull()?.type?.classifier
+            return thisType?.arguments?.firstOrNull()
         }
 
-        val COMPONENT_KEY_K_CLASS = ComponentKey::class
+        private val COMPONENT_KEY_K_CLASS = ComponentKey::class
     }
 }

mirai-core/src/commonTest/kotlin/network/component/ComponentKeyTest.kt

@@ -13,10 +13,19 @@ import net.mamoe.mirai.internal.test.AbstractTest
 import org.junit.jupiter.api.Test
 import kotlin.test.assertEquals
 
-private class TestComponent {
+private open class TestComponent {
     companion object : ComponentKey<TestComponent>
 }
 
+
+private interface MyInterface
+
+private open class TestComponentExt : TestComponent(), MyInterface
+
+private open class Key<R> : ComponentKey<R> where R : TestComponent, R : MyInterface
+private class KeyActual : Key<TestComponentExt>()
+
+
 internal class ComponentKeyTest : AbstractTest() {
 
     @Test
@@ -25,9 +34,38 @@ internal class ComponentKeyTest : AbstractTest() {
         assertEquals(TestComponent::class.qualifiedName!!, TestComponent.componentName(true))
     }
 
+    @Test
+    fun `componentName with erased type argument`() {
+        assertEquals(
+            "TestComponent & MyInterface",
+            Key<TestComponentExt>().componentName(false)
+        )
+        assertEquals(
+            "${TestComponent::class.qualifiedName!!} & ${MyInterface::class.qualifiedName!!}",
+            Key<TestComponentExt>().componentName(true)
+        )
+    }
+
+    @Test
+    fun `componentName with actual type argument`() {
+        assertEquals(
+            "TestComponentExt",
+            KeyActual().componentName(false)
+        )
+        assertEquals(
+            TestComponentExt::class.qualifiedName!!,
+            KeyActual().componentName(true)
+        )
+    }
+
     @Test
     fun `test smartToString`() {
         assertEquals("ComponentKey<TestComponent>", TestComponent.smartToString(false))
         assertEquals("ComponentKey<${TestComponent::class.qualifiedName!!}>", TestComponent.smartToString(true))
+        assertEquals(
+            "ComponentKey<${TestComponent::class.qualifiedName!!} & ${MyInterface::class.qualifiedName!!}>",
+            Key<TestComponentExt>().smartToString(true)
+        )
+        assertEquals("ComponentKey<${TestComponentExt::class.qualifiedName!!}>", KeyActual().smartToString(true))
     }
 }