FIR Java: support read of field constant initializers

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.builder.*
 import org.jetbrains.kotlin.fir.declarations.impl.FirResolvedDeclarationStatusImpl
+import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.builder.*
 import org.jetbrains.kotlin.fir.java.declarations.*
 import org.jetbrains.kotlin.fir.resolve.constructType
@@ -309,10 +310,16 @@ class JavaSymbolProvider(
                 isVar = !javaField.isFinal
                 isStatic = javaField.isStatic
                 addAnnotationsFrom(this@JavaSymbolProvider.session, javaField, javaTypeParameterStack)
+                initializer = convertJavaInitializerToFir(javaField.initializerValue)
             }
         }
     }
 
+    private fun convertJavaInitializerToFir(value: Any?): FirExpression? {
+        // NB: null should be converted to null
+        return value?.createConstantIfAny(session)
+    }
+
     private fun convertJavaMethodToFir(
         javaMethod: JavaMethod,
         classId: ClassId,

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaUtils.kt

@@ -451,7 +451,7 @@ private fun JavaAnnotationArgument.toFirExpression(
     // TODO: this.name
     return when (this) {
         is JavaLiteralAnnotationArgument -> {
-            value.createConstant(session)
+            value.createConstantOrError(session)
         }
         is JavaArrayAnnotationArgument -> buildArrayOfCall {
             argumentList = buildArgumentList {
@@ -503,13 +503,19 @@ private fun <T> List<T>.createArrayOfCall(session: FirSession, @Suppress("UNUSED
     return buildArrayOfCall {
         argumentList = buildArgumentList {
             for (element in this@createArrayOfCall) {
-                arguments += element.createConstant(session)
+                arguments += element.createConstantOrError(session)
             }
         }
     }
 }
 
-internal fun Any?.createConstant(session: FirSession): FirExpression {
+internal fun Any?.createConstantOrError(session: FirSession): FirExpression {
+    return createConstantIfAny(session) ?: buildErrorExpression {
+        diagnostic = ConeSimpleDiagnostic("Unknown value in JavaLiteralAnnotationArgument: $this", DiagnosticKind.Java)
+    }
+}
+
+internal fun Any?.createConstantIfAny(session: FirSession): FirExpression? {
     return when (this) {
         is Byte -> buildConstExpression(null, FirConstKind.Byte, this)
         is Short -> buildConstExpression(null, FirConstKind.Short, this)
@@ -530,9 +536,7 @@ internal fun Any?.createConstant(session: FirSession): FirExpression {
         is BooleanArray -> toList().createArrayOfCall(session, FirConstKind.Boolean)
         null -> buildConstExpression(null, FirConstKind.Null, null)
 
-        else -> buildErrorExpression {
-            diagnostic = ConeSimpleDiagnostic("Unknown value in JavaLiteralAnnotationArgument: $this", DiagnosticKind.Java)
-        }
+        else -> null
     }
 }
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/declarations/FirJavaField.kt

@@ -41,6 +41,7 @@ class FirJavaField @FirImplementationDetail constructor(
     override val isVar: Boolean,
     override val annotations: MutableList<FirAnnotationCall>,
     override val typeParameters: MutableList<FirTypeParameter>,
+    override var initializer: FirExpression?,
 ) : FirField() {
     init {
         symbol.bind(this)
@@ -71,6 +72,7 @@ class FirJavaField @FirImplementationDetail constructor(
 
     override fun <D> transformOtherChildren(transformer: FirTransformer<D>, data: D): FirField {
         transformAnnotations(transformer, data)
+        initializer = initializer?.transformSingle(transformer, data)
         return this
     }
 
@@ -86,6 +88,7 @@ class FirJavaField @FirImplementationDetail constructor(
         returnTypeRef.accept(visitor, data)
         annotations.forEach { it.accept(visitor, data) }
         typeParameters.forEach { it.accept(visitor, data) }
+        initializer?.accept(visitor, data)
     }
 
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirJavaField {
@@ -117,9 +120,6 @@ class FirJavaField @FirImplementationDetail constructor(
     override val delegate: FirExpression?
         get() = null
 
-    override val initializer: FirExpression?
-        get() = null
-
     override val delegateFieldSymbol: FirDelegateFieldSymbol<FirField>?
         get() = null
 
@@ -141,6 +141,7 @@ internal class FirJavaFieldBuilder : FirFieldBuilder() {
     var modality: Modality? = null
     lateinit var visibility: Visibility
     var isStatic: Boolean by Delegates.notNull()
+    var initializer: FirExpression? = null
 
     override var resolvePhase: FirResolvePhase = FirResolvePhase.ANALYZED_DEPENDENCIES
 
@@ -157,6 +158,7 @@ internal class FirJavaFieldBuilder : FirFieldBuilder() {
             isVar,
             annotations,
             typeParameters,
+            initializer,
         )
     }
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/deserialization/KotlinDeserializedJvmSymbolsProvider.kt

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.fir.diagnostics.DiagnosticKind
 import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.builder.*
 import org.jetbrains.kotlin.fir.java.JavaSymbolProvider
-import org.jetbrains.kotlin.fir.java.createConstant
+import org.jetbrains.kotlin.fir.java.createConstantOrError
 import org.jetbrains.kotlin.fir.java.topLevelName
 import org.jetbrains.kotlin.fir.references.builder.buildErrorNamedReference
 import org.jetbrains.kotlin.fir.references.builder.buildResolvedNamedReference
@@ -288,7 +288,7 @@ class KotlinDeserializedJvmSymbolsProvider(
             }
 
             private fun createConstant(value: Any?): FirExpression {
-                return value.createConstant(session)
+                return value.createConstantOrError(session)
             }
         }
     }

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/SignatureEnhancement.kt

@@ -102,6 +102,7 @@ class FirSignatureEnhancement(
                     isStatic = firElement.isStatic
                     annotations += firElement.annotations
                     status = firElement.status
+                    initializer = firElement.initializer
                 }
                 return symbol
             }