Support direct annotation instantiation in code gen on Kotlin 1.6 (#1390)

.github/workflows/build.yml

@@ -4,13 +4,24 @@ on: [push, pull_request]
 
 jobs:
   build:
-    name: 'Java ${{ matrix.java-version }} | KSP ${{ matrix.use-ksp }}'
+    name: 'Java ${{ matrix.java-version }} | Kotlin ${{ matrix.kotlin-version }} | KSP ${{ matrix.use-ksp }}'
     runs-on: ubuntu-latest
 
     strategy:
       fail-fast: false
       matrix:
         use-ksp: [ true, false ]
+        kotlin-version: [ '1.5.31', '1.6.0-RC' ]
+        ksp-version: [ '1.5.31-1.0.0', '1.6.0-RC-1.0.0' ]
+        exclude:
+          - kotlin-version: '1.5.31'
+            ksp-version: '1.6.0-RC-1.0.0'
+          - kotlin-version: '1.6.0-RC'
+            ksp-version: '1.5.31-1.0.0'
+
+    env:
+      MOSHI_KOTLIN_VERSION: '${{ matrix.kotlin-version }}'
+      MOSHI_KSP_VERSION: '${{ matrix.ksp-version }}'
 
     steps:
       - name: Checkout
@@ -36,8 +47,8 @@ jobs:
           java-version: '17'
 
       - name: Test
-        run: ./gradlew build check --stacktrace -PuseKsp=${{ matrix.use-ksp }}
+        run: ./gradlew build check --stacktrace -PuseKsp=${{ matrix.use-ksp }} -PkotlinVersion=${{ matrix.kotlin-version }}
 
       - name: Publish (default branch only)
-        if: github.repository == 'square/moshi' && github.ref == 'refs/heads/master'
+        if: github.repository == 'square/moshi' && github.ref == 'refs/heads/master' && matrix.kotlin-version == '1.5.31' && matrix.use-ksp == 'false'
         run: ./gradlew publish -PmavenCentralUsername=${{ secrets.SONATYPE_NEXUS_USERNAME }} -PmavenCentralPassword=${{ secrets.SONATYPE_NEXUS_PASSWORD }} --stacktrace

build.gradle.kts

@@ -23,7 +23,12 @@ import java.net.URL
 
 buildscript {
   dependencies {
-    classpath(kotlin("gradle-plugin", version = libs.versions.kotlin.get()))
+    val kotlinVersion = System.getenv("MOSHI_KOTLIN_VERSION")
+      ?: libs.versions.kotlin.get()
+    val kspVersion = System.getenv("MOSHI_KSP_VERSION")
+      ?: libs.versions.ksp.get()
+    classpath(kotlin("gradle-plugin", version = kotlinVersion))
+    classpath("com.google.devtools.ksp:symbol-processing-gradle-plugin:$kspVersion")
     // https://github.com/melix/japicmp-gradle-plugin/issues/36
     classpath("com.google.guava:guava:28.2-jre")
   }
@@ -125,8 +130,9 @@ subprojects {
   pluginManager.withPlugin("org.jetbrains.kotlin.jvm") {
     tasks.withType<KotlinCompile>().configureEach {
       kotlinOptions {
-        @Suppress("SuspiciousCollectionReassignment")
+        // TODO re-enable when no longer supporting multiple kotlin versions
-        freeCompilerArgs += listOf("-progressive")
+//        @Suppress("SuspiciousCollectionReassignment")
+//        freeCompilerArgs += listOf("-progressive")
         jvmTarget = libs.versions.jvmTarget.get()
       }
     }

gradle/libs.versions.toml

@@ -18,7 +18,7 @@ gjf = "1.11.0"
 jvmTarget = "1.8"
 kotlin = "1.5.31"
 kotlinCompileTesting = "1.4.4"
-kotlinpoet = "1.10.1"
+kotlinpoet = "1.10.2"
 ksp = "1.5.31-1.0.0"
 ktlint = "0.41.0"
 

kotlin/codegen/build.gradle.kts

@@ -20,7 +20,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
   kotlin("jvm")
-  alias(libs.plugins.ksp)
+  id("com.google.devtools.ksp")
   id("com.vanniktech.maven.publish")
   alias(libs.plugins.mavenShadow)
 }

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/AdapterGenerator.kt

@@ -185,26 +185,31 @@ internal class AdapterGenerator(
     result.addAnnotation(COMMON_SUPPRESS)
     result.addType(generatedAdapter)
     val proguardConfig = if (generateProguardRules) {
-      generatedAdapter.createProguardRule()
+      generatedAdapter.createProguardRule(target.instantiateAnnotations)
     } else {
       null
     }
     return PreparedAdapter(result.build(), proguardConfig)
   }
 
-  private fun TypeSpec.createProguardRule(): ProguardConfig {
+  private fun TypeSpec.createProguardRule(instantiateAnnotations: Boolean): ProguardConfig {
-    val adapterProperties = propertySpecs
+    val adapterProperties = if (instantiateAnnotations) {
-      .asSequence()
+      // Don't need to do anything special if we instantiate them directly!
-      .filter { prop ->
+      emptySet()
-        prop.type.rawType() == JsonAdapter::class.asClassName()
+    } else {
-      }
+      propertySpecs
-      .filter { prop -> prop.annotations.isNotEmpty() }
+        .asSequence()
-      .mapTo(mutableSetOf()) { prop ->
+        .filter { prop ->
-        QualifierAdapterProperty(
+          prop.type.rawType() == JsonAdapter::class.asClassName()
-          name = prop.name,
+        }
-          qualifiers = prop.annotations.mapTo(mutableSetOf()) { it.typeName.rawType() }
+        .filter { prop -> prop.annotations.isNotEmpty() }
-        )
+        .mapTo(mutableSetOf()) { prop ->
-      }
+          QualifierAdapterProperty(
+            name = prop.name,
+            qualifiers = prop.annotations.mapTo(mutableSetOf()) { it.typeName.rawType() }
+          )
+        }
+    }
 
     val adapterConstructorParams = when (requireNotNull(primaryConstructor).parameters.size) {
       1 -> listOf(CN_MOSHI.reflectionName())

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/DelegateKey.kt

@@ -17,6 +17,7 @@ package com.squareup.moshi.kotlin.codegen.api
 
 import com.squareup.kotlinpoet.AnnotationSpec
 import com.squareup.kotlinpoet.ClassName
+import com.squareup.kotlinpoet.CodeBlock
 import com.squareup.kotlinpoet.KModifier
 import com.squareup.kotlinpoet.MemberName
 import com.squareup.kotlinpoet.NameAllocator
@@ -29,6 +30,7 @@ import com.squareup.kotlinpoet.TypeVariableName
 import com.squareup.kotlinpoet.WildcardTypeName
 import com.squareup.kotlinpoet.asClassName
 import com.squareup.kotlinpoet.asTypeName
+import com.squareup.kotlinpoet.joinToCode
 import com.squareup.moshi.JsonAdapter
 import com.squareup.moshi.Types
 import java.util.Locale
@@ -36,7 +38,8 @@ import java.util.Locale
 /** A JsonAdapter that can be used to encode and decode a particular field. */
 internal data class DelegateKey(
   private val type: TypeName,
-  private val jsonQualifiers: List<AnnotationSpec>
+  private val jsonQualifiers: List<AnnotationSpec>,
+  private val instantiateAnnotations: Boolean
 ) {
   val nullable get() = type.isNullable
 
@@ -60,8 +63,12 @@ internal data class DelegateKey(
       moshiParameter,
       typeRenderer.render(type)
     )
+
     val (initializerString, args) = when {
       jsonQualifiers.isEmpty() -> ", %M()" to arrayOf(MemberName("kotlin.collections", "emptySet"))
+      instantiateAnnotations -> {
+        ", setOf(%L)" to arrayOf(jsonQualifiers.map { it.asInstantiationExpression() }.joinToCode())
+      }
       else -> {
         ", %T.getFieldJsonQualifierAnnotations(javaClass, " +
           "%S)" to arrayOf(Types::class.asTypeName(), adapterName)
@@ -70,12 +77,25 @@ internal data class DelegateKey(
     val finalArgs = arrayOf(*standardArgs, *args, propertyName)
 
     return PropertySpec.builder(adapterName, adapterTypeName, KModifier.PRIVATE)
-      .addAnnotations(jsonQualifiers)
+      .apply {
+        if (!instantiateAnnotations) {
+          addAnnotations(jsonQualifiers)
+        }
+      }
       .initializer("%N.adapter(%L$initializerString, %S)", *finalArgs)
       .build()
   }
 }
 
+private fun AnnotationSpec.asInstantiationExpression(): CodeBlock {
+  // <Type>(args)
+  return CodeBlock.of(
+    "%T(%L)",
+    typeName,
+    members.joinToCode()
+  )
+}
+
 /**
  * Returns a suggested variable name derived from a list of type names. This just concatenates,
  * yielding types like MapOfStringLong.

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/Options.kt

@@ -36,6 +36,14 @@ internal object Options {
    */
   const val OPTION_GENERATE_PROGUARD_RULES: String = "moshi.generateProguardRules"
 
+  /**
+   * This boolean processing option controls whether or not Moshi will directly instantiate
+   * JsonQualifier annotations in Kotlin 1.6+. Note that this is enabled by default in Kotlin 1.6
+   * but can be disabled to restore the legacy behavior of storing annotations on generated adapter
+   * fields and looking them up reflectively.
+   */
+  const val OPTION_INSTANTIATE_ANNOTATIONS: String = "moshi.instantiateAnnotations"
+
   val POSSIBLE_GENERATED_NAMES = arrayOf(
     ClassName("javax.annotation.processing", "Generated"),
     ClassName("javax.annotation", "Generated")

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/api/TargetType.kt

@@ -26,7 +26,8 @@ internal data class TargetType(
   val properties: Map<String, TargetProperty>,
   val typeVariables: List<TypeVariableName>,
   val isDataClass: Boolean,
-  val visibility: KModifier
+  val visibility: KModifier,
+  val instantiateAnnotations: Boolean
 ) {
 
   init {

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/apt/JsonClassCodegenProcessor.kt

@@ -23,6 +23,7 @@ import com.squareup.moshi.JsonClass
 import com.squareup.moshi.kotlin.codegen.api.AdapterGenerator
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATED
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATE_PROGUARD_RULES
+import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_INSTANTIATE_ANNOTATIONS
 import com.squareup.moshi.kotlin.codegen.api.Options.POSSIBLE_GENERATED_NAMES
 import com.squareup.moshi.kotlin.codegen.api.ProguardConfig
 import com.squareup.moshi.kotlin.codegen.api.PropertyGenerator
@@ -59,6 +60,7 @@ public class JsonClassCodegenProcessor : AbstractProcessor() {
   private val annotation = JsonClass::class.java
   private var generatedType: ClassName? = null
   private var generateProguardRules: Boolean = true
+  private var instantiateAnnotations: Boolean = true
 
   override fun getSupportedAnnotationTypes(): Set<String> = setOf(annotation.canonicalName)
 
@@ -76,6 +78,7 @@ public class JsonClassCodegenProcessor : AbstractProcessor() {
     }
 
     generateProguardRules = processingEnv.options[OPTION_GENERATE_PROGUARD_RULES]?.toBooleanStrictOrNull() ?: true
+    instantiateAnnotations = processingEnv.options[OPTION_INSTANTIATE_ANNOTATIONS]?.toBooleanStrictOrNull() ?: true
 
     this.types = processingEnv.typeUtils
     this.elements = processingEnv.elementUtils
@@ -135,11 +138,18 @@ public class JsonClassCodegenProcessor : AbstractProcessor() {
     element: TypeElement,
     cachedClassInspector: MoshiCachedClassInspector
   ): AdapterGenerator? {
-    val type = targetType(messager, elements, types, element, cachedClassInspector) ?: return null
+    val type = targetType(
+      messager,
+      elements,
+      types,
+      element,
+      cachedClassInspector,
+      instantiateAnnotations
+    ) ?: return null
 
     val properties = mutableMapOf<String, PropertyGenerator>()
     for (property in type.properties.values) {
-      val generator = property.generator(messager, element, elements)
+      val generator = property.generator(messager, element, elements, type.instantiateAnnotations)
       if (generator != null) {
         properties[property.name] = generator
       }

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/apt/metadata.kt

@@ -71,6 +71,7 @@ private val VISIBILITY_MODIFIERS = setOf(
   KModifier.PROTECTED,
   KModifier.PUBLIC
 )
+private val ANNOTATION_INSTANTIATION_MIN_VERSION = KotlinVersion(1, 6, 0)
 
 private fun Collection<KModifier>.visibility(): KModifier {
   return find { it in VISIBILITY_MODIFIERS } ?: KModifier.PUBLIC
@@ -122,7 +123,8 @@ internal fun targetType(
   elements: Elements,
   types: Types,
   element: TypeElement,
-  cachedClassInspector: MoshiCachedClassInspector
+  cachedClassInspector: MoshiCachedClassInspector,
+  instantiateAnnotationsEnabled: Boolean
 ): TargetType? {
   val typeMetadata = element.getAnnotation(Metadata::class.java)
   if (typeMetadata == null) {
@@ -204,6 +206,11 @@ internal fun targetType(
     }
   }
 
+  val instantiateAnnotations = instantiateAnnotationsEnabled && run {
+    val (major, minor, patch) = typeMetadata.metadataVersion
+    val languageVersion = KotlinVersion(major, minor, patch)
+    languageVersion >= ANNOTATION_INSTANTIATION_MIN_VERSION
+  }
   val kotlinApi = cachedClassInspector.toTypeSpec(kmClass)
   val typeVariables = kotlinApi.typeVariables
   val appliedType = AppliedType.get(element)
@@ -319,7 +326,8 @@ internal fun targetType(
     properties = properties,
     typeVariables = typeVariables,
     isDataClass = KModifier.DATA in kotlinApi.modifiers,
-    visibility = resolvedVisibility
+    visibility = resolvedVisibility,
+    instantiateAnnotations = instantiateAnnotations
   )
 }
 
@@ -418,7 +426,8 @@ private val TargetProperty.isVisible: Boolean
 internal fun TargetProperty.generator(
   messager: Messager,
   sourceElement: TypeElement,
-  elements: Elements
+  elements: Elements,
+  instantiateAnnotations: Boolean
 ): PropertyGenerator? {
   if (isTransient) {
     if (!hasDefault) {
@@ -429,7 +438,7 @@ internal fun TargetProperty.generator(
       )
       return null
     }
-    return PropertyGenerator(this, DelegateKey(type, emptyList()), true)
+    return PropertyGenerator(this, DelegateKey(type, emptyList(), instantiateAnnotations), true)
   }
 
   if (!isVisible) {
@@ -452,6 +461,7 @@ internal fun TargetProperty.generator(
     // Check Java types since that covers both Java and Kotlin annotations.
     val annotationElement = elements.getTypeElement(qualifierRawType.canonicalName)
       ?: continue
+
     annotationElement.getAnnotation(Retention::class.java)?.let {
       if (it.value != RetentionPolicy.RUNTIME) {
         messager.printMessage(
@@ -460,12 +470,14 @@ internal fun TargetProperty.generator(
         )
       }
     }
-    annotationElement.getAnnotation(Target::class.java)?.let {
+    if (!instantiateAnnotations) {
-      if (ElementType.FIELD !in it.value) {
+      annotationElement.getAnnotation(Target::class.java)?.let {
-        messager.printMessage(
+        if (ElementType.FIELD !in it.value) {
-          ERROR,
+          messager.printMessage(
-          "JsonQualifier @${qualifierRawType.simpleName} must support FIELD target"
+            ERROR,
-        )
+            "JsonQualifier @${qualifierRawType.simpleName} must support FIELD target"
+          )
+        }
       }
     }
   }
@@ -478,7 +490,7 @@ internal fun TargetProperty.generator(
 
   return PropertyGenerator(
     this,
-    DelegateKey(type, jsonQualifierSpecs)
+    DelegateKey(type, jsonQualifierSpecs, instantiateAnnotations)
   )
 }
 

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/ksp/JsonClassSymbolProcessorProvider.kt

@@ -34,6 +34,7 @@ import com.squareup.moshi.JsonClass
 import com.squareup.moshi.kotlin.codegen.api.AdapterGenerator
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATED
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATE_PROGUARD_RULES
+import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_INSTANTIATE_ANNOTATIONS
 import com.squareup.moshi.kotlin.codegen.api.Options.POSSIBLE_GENERATED_NAMES
 import com.squareup.moshi.kotlin.codegen.api.ProguardConfig
 import com.squareup.moshi.kotlin.codegen.api.PropertyGenerator
@@ -63,6 +64,8 @@ private class JsonClassSymbolProcessor(
     }
   }
   private val generateProguardRules = environment.options[OPTION_GENERATE_PROGUARD_RULES]?.toBooleanStrictOrNull() ?: true
+  private val instantiateAnnotations = (environment.options[OPTION_INSTANTIATE_ANNOTATIONS]?.toBooleanStrictOrNull() ?: true) &&
+    environment.kotlinVersion.isAtLeast(1, 6)
 
   override fun process(resolver: Resolver): List<KSAnnotated> {
     val generatedAnnotation = generatedOption?.let {
@@ -122,11 +125,11 @@ private class JsonClassSymbolProcessor(
     resolver: Resolver,
     originalType: KSDeclaration,
   ): AdapterGenerator? {
-    val type = targetType(originalType, resolver, logger) ?: return null
+    val type = targetType(originalType, resolver, logger, instantiateAnnotations) ?: return null
 
     val properties = mutableMapOf<String, PropertyGenerator>()
     for (property in type.properties.values) {
-      val generator = property.generator(logger, resolver, originalType)
+      val generator = property.generator(logger, resolver, originalType, type.instantiateAnnotations)
       if (generator != null) {
         properties[property.name] = generator
       }

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/ksp/KspUtil.kt

@@ -69,12 +69,12 @@ private fun addValueToBlock(value: Any, resolver: Resolver, member: CodeBlock.Bu
   when (value) {
     is List<*> -> {
       // Array type
-      member.add("[⇥⇥")
+      member.add("arrayOf(⇥⇥")
       value.forEachIndexed { index, innerValue ->
         if (index > 0) member.add(", ")
         addValueToBlock(innerValue!!, resolver, member)
       }
-      member.add("⇤⇤]")
+      member.add("⇤⇤)")
     }
     is KSType -> {
       val unwrapped = value.unwrapTypeAlias()

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/ksp/MoshiApiUtil.kt

@@ -28,17 +28,6 @@ import com.squareup.moshi.kotlin.codegen.api.PropertyGenerator
 import com.squareup.moshi.kotlin.codegen.api.TargetProperty
 import com.squareup.moshi.kotlin.codegen.api.rawType
 
-private val VISIBILITY_MODIFIERS = setOf(
-  KModifier.INTERNAL,
-  KModifier.PRIVATE,
-  KModifier.PROTECTED,
-  KModifier.PUBLIC
-)
-
-internal fun Collection<KModifier>.visibility(): KModifier {
-  return find { it in VISIBILITY_MODIFIERS } ?: KModifier.PUBLIC
-}
-
 private val TargetProperty.isTransient get() = propertySpec.annotations.any { it.typeName == Transient::class.asClassName() }
 private val TargetProperty.isSettable get() = propertySpec.mutable || parameter != null
 private val TargetProperty.isVisible: Boolean
@@ -55,7 +44,8 @@ private val TargetProperty.isVisible: Boolean
 internal fun TargetProperty.generator(
   logger: KSPLogger,
   resolver: Resolver,
-  originalType: KSDeclaration
+  originalType: KSDeclaration,
+  instantiateAnnotations: Boolean
 ): PropertyGenerator? {
   if (isTransient) {
     if (!hasDefault) {
@@ -65,7 +55,7 @@ internal fun TargetProperty.generator(
       )
       return null
     }
-    return PropertyGenerator(this, DelegateKey(type, emptyList()), true)
+    return PropertyGenerator(this, DelegateKey(type, emptyList(), instantiateAnnotations), true)
   }
 
   if (!isVisible) {
@@ -93,11 +83,13 @@ internal fun TargetProperty.generator(
           )
         }
       }
-      annotationElement.findAnnotationWithType<Target>()?.let {
+      if (!instantiateAnnotations) {
-        if (AnnotationTarget.FIELD !in it.allowedTargets) {
+        annotationElement.findAnnotationWithType<Target>()?.let {
-          logger.error(
+          if (AnnotationTarget.FIELD !in it.allowedTargets) {
-            "JsonQualifier @${qualifierRawType.simpleName} must support FIELD target"
+            logger.error(
-          )
+              "JsonQualifier @${qualifierRawType.simpleName} must support FIELD target"
+            )
+          }
         }
       }
     }
@@ -111,7 +103,7 @@ internal fun TargetProperty.generator(
 
   return PropertyGenerator(
     this,
-    DelegateKey(type, jsonQualifierSpecs)
+    DelegateKey(type, jsonQualifierSpecs, instantiateAnnotations)
   )
 }
 

kotlin/codegen/src/main/java/com/squareup/moshi/kotlin/codegen/ksp/TargetTypes.kt

@@ -58,6 +58,7 @@ internal fun targetType(
   type: KSDeclaration,
   resolver: Resolver,
   logger: KSPLogger,
+  instantiateAnnotations: Boolean
 ): TargetType? {
   if (type !is KSClassDeclaration) {
     logger.error("@JsonClass can't be applied to ${type.qualifiedName?.asString()}: must be a Kotlin class", type)
@@ -152,7 +153,8 @@ internal fun targetType(
     properties = properties,
     typeVariables = typeVariables,
     isDataClass = Modifier.DATA in type.modifiers,
-    visibility = resolvedVisibility
+    visibility = resolvedVisibility,
+    instantiateAnnotations = instantiateAnnotations
   )
 }
 

kotlin/codegen/src/test/java/com/squareup/moshi/kotlin/codegen/apt/JsonClassCodegenProcessorTest.kt

@@ -18,9 +18,9 @@ package com.squareup.moshi.kotlin.codegen.apt
 import com.google.common.truth.Truth.assertThat
 import com.squareup.moshi.JsonAdapter
 import com.squareup.moshi.JsonReader
-import com.squareup.moshi.kotlin.codegen.api.Options
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATED
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATE_PROGUARD_RULES
+import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_INSTANTIATE_ANNOTATIONS
 import com.tschuchort.compiletesting.KotlinCompilation
 import com.tschuchort.compiletesting.SourceFile
 import com.tschuchort.compiletesting.SourceFile.Companion.kotlin
@@ -28,6 +28,8 @@ import org.junit.Ignore
 import org.junit.Rule
 import org.junit.Test
 import org.junit.rules.TemporaryFolder
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
 import kotlin.reflect.KClass
 import kotlin.reflect.KClassifier
 import kotlin.reflect.KType
@@ -38,7 +40,24 @@ import kotlin.reflect.full.createType
 import kotlin.reflect.full.declaredMemberProperties
 
 /** Execute kotlinc to confirm that either files are generated or errors are printed. */
-class JsonClassCodegenProcessorTest {
+@RunWith(Parameterized::class)
+class JsonClassCodegenProcessorTest(
+  private val languageVersion: String,
+  private val instantiateAnnotations: Boolean
+) {
+
+  companion object {
+    @JvmStatic
+    @Parameterized.Parameters(name = "languageVersion={0},instantiateAnnotations={1}")
+    fun data(): Collection<Array<Any>> {
+      return listOf(
+        arrayOf("1.5", true),
+        arrayOf("1.6", true),
+        arrayOf("1.6", false)
+      )
+    }
+  }
+
   @Rule @JvmField var temporaryFolder: TemporaryFolder = TemporaryFolder()
 
   @Test
@@ -455,8 +474,13 @@ class JsonClassCodegenProcessorTest {
           """
       )
     )
-    assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.COMPILATION_ERROR)
+    if (languageVersion == "1.5" || !instantiateAnnotations) {
-    assertThat(result.messages).contains("JsonQualifier @UpperCase must support FIELD target")
+      assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.COMPILATION_ERROR)
+      assertThat(result.messages).contains("JsonQualifier @UpperCase must support FIELD target")
+    } else {
+      // We instantiate directly!
+      assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+    }
   }
 
   @Test
@@ -665,19 +689,34 @@ class JsonClassCodegenProcessorTest {
           }
           """.trimIndent()
         )
-        "moshi-testPackage.UsingQualifiers" -> assertThat(generatedFile.readText()).contains(
+        "moshi-testPackage.UsingQualifiers" -> {
-          """
+          if (languageVersion == "1.5" || !instantiateAnnotations) {
-          -if class testPackage.UsingQualifiers
+            assertThat(generatedFile.readText()).contains(
-          -keepnames class testPackage.UsingQualifiers
+              """
-          -if class testPackage.UsingQualifiers
+              -if class testPackage.UsingQualifiers
-          -keep class testPackage.UsingQualifiersJsonAdapter {
+              -keepnames class testPackage.UsingQualifiers
-              public <init>(com.squareup.moshi.Moshi);
+              -if class testPackage.UsingQualifiers
-              private com.squareup.moshi.JsonAdapter stringAtMyQualifierAdapter;
+              -keep class testPackage.UsingQualifiersJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+                  private com.squareup.moshi.JsonAdapter stringAtMyQualifierAdapter;
+              }
+              -if class testPackage.UsingQualifiers
+              -keep @interface testPackage.MyQualifier
+              """.trimIndent()
+            )
+          } else {
+            assertThat(generatedFile.readText()).contains(
+              """
+              -if class testPackage.UsingQualifiers
+              -keepnames class testPackage.UsingQualifiers
+              -if class testPackage.UsingQualifiers
+              -keep class testPackage.UsingQualifiersJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+              }
+              """.trimIndent()
+            )
           }
-          -if class testPackage.UsingQualifiers
+        }
-          -keep @interface testPackage.MyQualifier
-          """.trimIndent()
-        )
         "moshi-testPackage.MixedTypes" -> assertThat(generatedFile.readText()).contains(
           """
           -if class testPackage.MixedTypes
@@ -704,25 +743,46 @@ class JsonClassCodegenProcessorTest {
           }
           """.trimIndent()
         )
-        "moshi-testPackage.Complex" -> assertThat(generatedFile.readText()).contains(
+        "moshi-testPackage.Complex" -> {
-          """
+          if (languageVersion == "1.5" || !instantiateAnnotations) {
-          -if class testPackage.Complex
+            assertThat(generatedFile.readText()).contains(
-          -keepnames class testPackage.Complex
+              """
-          -if class testPackage.Complex
+              -if class testPackage.Complex
-          -keep class testPackage.ComplexJsonAdapter {
+              -keepnames class testPackage.Complex
-              public <init>(com.squareup.moshi.Moshi,java.lang.reflect.Type[]);
+              -if class testPackage.Complex
-              private com.squareup.moshi.JsonAdapter mutableListOfStringAtMyQualifierAdapter;
+              -keep class testPackage.ComplexJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi,java.lang.reflect.Type[]);
+                  private com.squareup.moshi.JsonAdapter mutableListOfStringAtMyQualifierAdapter;
+              }
+              -if class testPackage.Complex
+              -keep @interface testPackage.MyQualifier
+              -if class testPackage.Complex
+              -keepnames class kotlin.jvm.internal.DefaultConstructorMarker
+              -if class testPackage.Complex
+              -keepclassmembers class testPackage.Complex {
+                  public synthetic <init>(java.lang.String,java.util.List,java.lang.Object,int,kotlin.jvm.internal.DefaultConstructorMarker);
+              }
+              """.trimIndent()
+            )
+          } else {
+            assertThat(generatedFile.readText()).contains(
+              """
+              -if class testPackage.Complex
+              -keepnames class testPackage.Complex
+              -if class testPackage.Complex
+              -keep class testPackage.ComplexJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi,java.lang.reflect.Type[]);
+              }
+              -if class testPackage.Complex
+              -keepnames class kotlin.jvm.internal.DefaultConstructorMarker
+              -if class testPackage.Complex
+              -keepclassmembers class testPackage.Complex {
+                  public synthetic <init>(java.lang.String,java.util.List,java.lang.Object,int,kotlin.jvm.internal.DefaultConstructorMarker);
+              }
+              """.trimIndent()
+            )
           }
-          -if class testPackage.Complex
+        }
-          -keep @interface testPackage.MyQualifier
-          -if class testPackage.Complex
-          -keepnames class kotlin.jvm.internal.DefaultConstructorMarker
-          -if class testPackage.Complex
-          -keepclassmembers class testPackage.Complex {
-              public synthetic <init>(java.lang.String,java.util.List,java.lang.Object,int,kotlin.jvm.internal.DefaultConstructorMarker);
-          }
-          """.trimIndent()
-        )
         "moshi-testPackage.MultipleMasks" -> assertThat(generatedFile.readText()).contains(
           """
           -if class testPackage.MultipleMasks
@@ -739,19 +799,34 @@ class JsonClassCodegenProcessorTest {
           }
           """.trimIndent()
         )
-        "moshi-testPackage.NestedType.NestedSimple" -> assertThat(generatedFile.readText()).contains(
+        "moshi-testPackage.NestedType.NestedSimple" -> {
-          """
+          if (languageVersion == "1.5" || !instantiateAnnotations) {
-          -if class testPackage.NestedType${'$'}NestedSimple
+            assertThat(generatedFile.readText()).contains(
-          -keepnames class testPackage.NestedType${'$'}NestedSimple
+              """
-          -if class testPackage.NestedType${'$'}NestedSimple
+              -if class testPackage.NestedType${'$'}NestedSimple
-          -keep class testPackage.NestedType_NestedSimpleJsonAdapter {
+              -keepnames class testPackage.NestedType${'$'}NestedSimple
-              public <init>(com.squareup.moshi.Moshi);
+              -if class testPackage.NestedType${'$'}NestedSimple
-              private com.squareup.moshi.JsonAdapter stringAtNestedQualifierAdapter;
+              -keep class testPackage.NestedType_NestedSimpleJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+                  private com.squareup.moshi.JsonAdapter stringAtNestedQualifierAdapter;
+              }
+              -if class testPackage.NestedType${'$'}NestedSimple
+              -keep @interface testPackage.NestedType${'$'}NestedQualifier
+              """.trimIndent()
+            )
+          } else {
+            assertThat(generatedFile.readText()).contains(
+              """
+              -if class testPackage.NestedType${'$'}NestedSimple
+              -keepnames class testPackage.NestedType${'$'}NestedSimple
+              -if class testPackage.NestedType${'$'}NestedSimple
+              -keep class testPackage.NestedType_NestedSimpleJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+              }
+              """.trimIndent()
+            )
           }
-          -if class testPackage.NestedType${'$'}NestedSimple
+        }
-          -keep @interface testPackage.NestedType${'$'}NestedQualifier
-          """.trimIndent()
-        )
         else -> error("Unexpected proguard file! ${generatedFile.name}")
       }
     }
@@ -765,6 +840,8 @@ class JsonClassCodegenProcessorTest {
         inheritClassPath = true
         sources = sourceFiles.asList()
         verbose = false
+        kotlincArguments = listOf("-language-version", languageVersion)
+        kaptArgs[OPTION_INSTANTIATE_ANNOTATIONS] = "$instantiateAnnotations"
       }
   }
 

kotlin/codegen/src/test/java/com/squareup/moshi/kotlin/codegen/ksp/JsonClassSymbolProcessorTest.kt

@@ -16,6 +16,7 @@
 package com.squareup.moshi.kotlin.codegen.ksp
 
 import com.google.common.truth.Truth.assertThat
+import com.squareup.moshi.kotlin.codegen.api.Options
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATED
 import com.squareup.moshi.kotlin.codegen.api.Options.OPTION_GENERATE_PROGUARD_RULES
 import com.tschuchort.compiletesting.KotlinCompilation
@@ -30,15 +31,41 @@ import org.junit.Ignore
 import org.junit.Rule
 import org.junit.Test
 import org.junit.rules.TemporaryFolder
-import kotlin.reflect.KClassifier
+import org.junit.runner.RunWith
-import kotlin.reflect.KType
+import org.junit.runners.Parameterized
-import kotlin.reflect.KTypeProjection
-import kotlin.reflect.KVariance
-import kotlin.reflect.KVariance.INVARIANT
-import kotlin.reflect.full.createType
 
 /** Execute kotlinc to confirm that either files are generated or errors are printed. */
-class JsonClassSymbolProcessorTest {
+@RunWith(Parameterized::class)
+class JsonClassSymbolProcessorTest(
+  private val languageVersion: String,
+  private val instantiateAnnotations: Boolean
+) {
+
+  companion object {
+    @JvmStatic
+    @Parameterized.Parameters(name = "languageVersion={0},instantiateAnnotations={1}")
+    fun data(): Collection<Array<Any>> {
+      // TODO KSP doesn't recognize language version yet https://github.com/google/ksp/issues/611
+      //  toe-holds for the future
+      val runtimeVersion = KotlinVersion.CURRENT
+      return mutableListOf<Array<Any>>().apply {
+        if (runtimeVersion.major != 1 || runtimeVersion.minor != 6) {
+          // True by default but still 1.5
+          // Can't test when running with 1.6 because lang version is still 1.6 per above comment
+          add(arrayOf("1.5", true))
+        }
+        // Redundant case, set to false but still 1.5
+        add(arrayOf("1.5", false))
+        if (runtimeVersion.major != 1 || runtimeVersion.minor != 5) {
+          // Happy case - 1.6 and true by default
+          // Can't test when running with 1.5 because lang version is still 1.5 per above comment
+          add(arrayOf("1.6", true))
+        }
+        // 1.6 but explicitly disabled
+        add(arrayOf("1.6", false))
+      }
+    }
+  }
 
   @Rule @JvmField var temporaryFolder: TemporaryFolder = TemporaryFolder()
 
@@ -490,8 +517,13 @@ class JsonClassSymbolProcessorTest {
           """
       )
     )
-    assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.COMPILATION_ERROR)
+    if (languageVersion == "1.5" || !instantiateAnnotations) {
-    assertThat(result.messages).contains("JsonQualifier @UpperCase must support FIELD target")
+      assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.COMPILATION_ERROR)
+      assertThat(result.messages).contains("JsonQualifier @UpperCase must support FIELD target")
+    } else {
+      // We instantiate directly!
+      assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+    }
   }
 
   @Test
@@ -704,19 +736,34 @@ class JsonClassSymbolProcessorTest {
           }
           """.trimIndent()
         )
-        "moshi-testPackage.UsingQualifiers" -> assertThat(generatedFile.readText()).contains(
+        "moshi-testPackage.UsingQualifiers" -> {
-          """
+          if (languageVersion == "1.5" || !instantiateAnnotations) {
-          -if class testPackage.UsingQualifiers
+            assertThat(generatedFile.readText()).contains(
-          -keepnames class testPackage.UsingQualifiers
+              """
-          -if class testPackage.UsingQualifiers
+              -if class testPackage.UsingQualifiers
-          -keep class testPackage.UsingQualifiersJsonAdapter {
+              -keepnames class testPackage.UsingQualifiers
-              public <init>(com.squareup.moshi.Moshi);
+              -if class testPackage.UsingQualifiers
-              private com.squareup.moshi.JsonAdapter stringAtMyQualifierAdapter;
+              -keep class testPackage.UsingQualifiersJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+                  private com.squareup.moshi.JsonAdapter stringAtMyQualifierAdapter;
+              }
+              -if class testPackage.UsingQualifiers
+              -keep @interface testPackage.MyQualifier
+              """.trimIndent()
+            )
+          } else {
+            assertThat(generatedFile.readText()).contains(
+              """
+              -if class testPackage.UsingQualifiers
+              -keepnames class testPackage.UsingQualifiers
+              -if class testPackage.UsingQualifiers
+              -keep class testPackage.UsingQualifiersJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+              }
+              """.trimIndent()
+            )
           }
-          -if class testPackage.UsingQualifiers
+        }
-          -keep @interface testPackage.MyQualifier
-          """.trimIndent()
-        )
         "moshi-testPackage.MixedTypes" -> assertThat(generatedFile.readText()).contains(
           """
           -if class testPackage.MixedTypes
@@ -743,25 +790,46 @@ class JsonClassSymbolProcessorTest {
           }
           """.trimIndent()
         )
-        "moshi-testPackage.Complex" -> assertThat(generatedFile.readText()).contains(
+        "moshi-testPackage.Complex" -> {
-          """
+          if (languageVersion == "1.5" || !instantiateAnnotations) {
-          -if class testPackage.Complex
+            assertThat(generatedFile.readText()).contains(
-          -keepnames class testPackage.Complex
+              """
-          -if class testPackage.Complex
+              -if class testPackage.Complex
-          -keep class testPackage.ComplexJsonAdapter {
+              -keepnames class testPackage.Complex
-              public <init>(com.squareup.moshi.Moshi,java.lang.reflect.Type[]);
+              -if class testPackage.Complex
-              private com.squareup.moshi.JsonAdapter mutableListOfStringAtMyQualifierAdapter;
+              -keep class testPackage.ComplexJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi,java.lang.reflect.Type[]);
+                  private com.squareup.moshi.JsonAdapter mutableListOfStringAtMyQualifierAdapter;
+              }
+              -if class testPackage.Complex
+              -keep @interface testPackage.MyQualifier
+              -if class testPackage.Complex
+              -keepnames class kotlin.jvm.internal.DefaultConstructorMarker
+              -if class testPackage.Complex
+              -keepclassmembers class testPackage.Complex {
+                  public synthetic <init>(java.lang.String,java.util.List,java.lang.Object,int,kotlin.jvm.internal.DefaultConstructorMarker);
+              }
+              """.trimIndent()
+            )
+          } else {
+            assertThat(generatedFile.readText()).contains(
+              """
+              -if class testPackage.Complex
+              -keepnames class testPackage.Complex
+              -if class testPackage.Complex
+              -keep class testPackage.ComplexJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi,java.lang.reflect.Type[]);
+              }
+              -if class testPackage.Complex
+              -keepnames class kotlin.jvm.internal.DefaultConstructorMarker
+              -if class testPackage.Complex
+              -keepclassmembers class testPackage.Complex {
+                  public synthetic <init>(java.lang.String,java.util.List,java.lang.Object,int,kotlin.jvm.internal.DefaultConstructorMarker);
+              }
+              """.trimIndent()
+            )
           }
-          -if class testPackage.Complex
+        }
-          -keep @interface testPackage.MyQualifier
-          -if class testPackage.Complex
-          -keepnames class kotlin.jvm.internal.DefaultConstructorMarker
-          -if class testPackage.Complex
-          -keepclassmembers class testPackage.Complex {
-              public synthetic <init>(java.lang.String,java.util.List,java.lang.Object,int,kotlin.jvm.internal.DefaultConstructorMarker);
-          }
-          """.trimIndent()
-        )
         "moshi-testPackage.MultipleMasks" -> assertThat(generatedFile.readText()).contains(
           """
           -if class testPackage.MultipleMasks
@@ -778,19 +846,34 @@ class JsonClassSymbolProcessorTest {
           }
           """.trimIndent()
         )
-        "moshi-testPackage.NestedType.NestedSimple" -> assertThat(generatedFile.readText()).contains(
+        "moshi-testPackage.NestedType.NestedSimple" -> {
-          """
+          if (languageVersion == "1.5" || !instantiateAnnotations) {
-          -if class testPackage.NestedType${'$'}NestedSimple
+            assertThat(generatedFile.readText()).contains(
-          -keepnames class testPackage.NestedType${'$'}NestedSimple
+              """
-          -if class testPackage.NestedType${'$'}NestedSimple
+              -if class testPackage.NestedType${'$'}NestedSimple
-          -keep class testPackage.NestedType_NestedSimpleJsonAdapter {
+              -keepnames class testPackage.NestedType${'$'}NestedSimple
-              public <init>(com.squareup.moshi.Moshi);
+              -if class testPackage.NestedType${'$'}NestedSimple
-              private com.squareup.moshi.JsonAdapter stringAtNestedQualifierAdapter;
+              -keep class testPackage.NestedType_NestedSimpleJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+                  private com.squareup.moshi.JsonAdapter stringAtNestedQualifierAdapter;
+              }
+              -if class testPackage.NestedType${'$'}NestedSimple
+              -keep @interface testPackage.NestedType${'$'}NestedQualifier
+              """.trimIndent()
+            )
+          } else {
+            assertThat(generatedFile.readText()).contains(
+              """
+              -if class testPackage.NestedType${'$'}NestedSimple
+              -keepnames class testPackage.NestedType${'$'}NestedSimple
+              -if class testPackage.NestedType${'$'}NestedSimple
+              -keep class testPackage.NestedType_NestedSimpleJsonAdapter {
+                  public <init>(com.squareup.moshi.Moshi);
+              }
+              """.trimIndent()
+            )
           }
-          -if class testPackage.NestedType${'$'}NestedSimple
+        }
-          -keep @interface testPackage.NestedType${'$'}NestedQualifier
-          """.trimIndent()
-        )
         else -> error("Unexpected proguard file! ${generatedFile.name}")
       }
     }
@@ -805,20 +888,12 @@ class JsonClassSymbolProcessorTest {
         sources = sourceFiles.asList()
         verbose = false
         kspIncremental = true // The default now
+        kotlincArguments = listOf("-language-version", languageVersion)
+        kspArgs[Options.OPTION_INSTANTIATE_ANNOTATIONS] = "$instantiateAnnotations"
       }
   }
 
   private fun compile(vararg sourceFiles: SourceFile): KotlinCompilation.Result {
     return prepareCompilation(*sourceFiles).compile()
   }
-
-  private fun KClassifier.parameterizedBy(vararg types: KType): KType {
-    return createType(
-      types.map { it.asProjection() }
-    )
-  }
-
-  private fun KType.asProjection(variance: KVariance? = INVARIANT): KTypeProjection {
-    return KTypeProjection(variance, this)
-  }
 }

kotlin/tests/build.gradle.kts

@@ -19,7 +19,7 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 plugins {
   kotlin("jvm")
   kotlin("kapt") apply false
-  alias(libs.plugins.ksp) apply false
+  id("com.google.devtools.ksp") apply false
 }
 
 val useKsp = hasProperty("useKsp")
@@ -34,11 +34,14 @@ tasks.withType<Test>().configureEach {
   jvmArgs("--add-opens=java.base/java.io=ALL-UNNAMED")
 }
 
+val useWError = findProperty("kotlinLanguageVersion")?.toString()
+  ?.startsWith("1.5")
+  ?: false
 tasks.withType<KotlinCompile>().configureEach {
   kotlinOptions {
+    allWarningsAsErrors = useWError
     @Suppress("SuspiciousCollectionReassignment")
     freeCompilerArgs += listOf(
-      "-Werror",
       "-Xopt-in=kotlin.ExperimentalStdlibApi"
     )
   }