KSP2: Fix KSPropertyDeclaration.isMutable for Java libs

(cherry picked from commit a7611f2)

Author: ting-yuan

compiler-plugin/src/test/kotlin/com/google/devtools/ksp/test/KSPCompilerPluginTest.kt

@@ -321,6 +321,12 @@ class KSPCompilerPluginTest : AbstractKSPCompilerPluginTest() {
         runTest("../test-utils/testData/api/interfaceWithDefault.kt")
     }
 
+    @TestMetadata("isMutable.kt")
+    @Test
+    fun testIsMutable() {
+        runTest("../test-utils/testData/api/isMutable.kt")
+    }
+
     @TestMetadata("javaModifiers.kt")
     @Test
     fun testJavaModifiers() {

kotlin-analysis-api/src/main/kotlin/com/google/devtools/ksp/impl/symbol/kotlin/KSPropertyDeclarationJavaImpl.kt

@@ -31,7 +31,7 @@ class KSPropertyDeclarationJavaImpl private constructor(val ktJavaFieldSymbol: K
     }
 
     override val isMutable: Boolean
-        get() = !modifiers.contains(Modifier.FINAL)
+        get() = !ktJavaFieldSymbol.isVal
 
     override val hasBackingField: Boolean
         get() = true

kotlin-analysis-api/src/test/kotlin/com/google/devtools/ksp/test/KSPAATest.kt

@@ -358,6 +358,12 @@ class KSPAATest : AbstractKSPAATest() {
         runTest("../test-utils/testData/api/interfaceWithDefault.kt")
     }
 
+    @TestMetadata("isMutable.kt")
+    @Test
+    fun testIsMutable() {
+        runTest("../test-utils/testData/api/isMutable.kt")
+    }
+
     @TestMetadata("javaModifiers.kt")
     @Test
     fun testJavaModifiers() {

test-utils/src/main/kotlin/com/google/devtools/ksp/processor/IsMutableProcessor.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2021 Google LLC
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.devtools.ksp.processor
+
+import com.google.devtools.ksp.KspExperimental
+import com.google.devtools.ksp.processing.Resolver
+import com.google.devtools.ksp.symbol.KSAnnotated
+import com.google.devtools.ksp.symbol.KSNode
+import com.google.devtools.ksp.symbol.KSPropertyDeclaration
+import com.google.devtools.ksp.visitor.KSTopDownVisitor
+
+@Suppress("unused") // used in tests
+@OptIn(KspExperimental::class)
+open class IsMutableProcessor : AbstractTestProcessor() {
+    lateinit var results: List<String>
+
+    override fun process(resolver: Resolver): List<KSAnnotated> {
+        results = listOf("lib", "main").flatMap { pkg ->
+            resolver.getDeclarationsFromPackage(pkg)
+                .flatMap { declaration ->
+                    val properties = mutableListOf<KSPropertyDeclaration>()
+                    declaration.accept(AllMembersVisitor(), properties)
+                    properties
+                }.map {
+                    "${it.qualifiedName?.asString()}: ${it.isMutable}"
+                }.sorted()
+        }
+        return emptyList()
+    }
+
+    private class AllMembersVisitor : KSTopDownVisitor<MutableList<KSPropertyDeclaration>, Unit>() {
+        override fun defaultHandler(node: KSNode, data: MutableList<KSPropertyDeclaration>) {
+        }
+
+        override fun visitPropertyDeclaration(
+            property: KSPropertyDeclaration,
+            data: MutableList<KSPropertyDeclaration>
+        ) {
+            data.add(property)
+            super.visitPropertyDeclaration(property, data)
+        }
+    }
+
+    override fun toResult(): List<String> {
+        return results
+    }
+}