Do not serialize empty property signature to JVM metadata

This should have no effect on the correct code currently because all
properties have at least a getter, but may help in debugging problems
with serialized metadata for properties

compiler/backend/src/org/jetbrains/kotlin/codegen/serialization/JvmSerializerExtension.kt

@@ -178,7 +178,9 @@ class JvmSerializerExtension(private val bindings: JvmSerializationBindings, sta
             if (setterMethod != null) signatureSerializer.methodSignature(null, setterMethod) else null
         )
 
-        proto.setExtension(JvmProtoBuf.propertySignature, signature)
+        if (signature != null) {
+            proto.setExtension(JvmProtoBuf.propertySignature, signature)
+        }
 
         if (descriptor.isJvmFieldPropertyInInterfaceCompanion()) {
             proto.setExtension(JvmProtoBuf.flags, JvmFlags.getPropertyFlags(true))
@@ -262,7 +264,7 @@ class JvmSerializerExtension(private val bindings: JvmSerializationBindings, sta
             syntheticMethod: JvmProtoBuf.JvmMethodSignature?,
             getter: JvmProtoBuf.JvmMethodSignature?,
             setter: JvmProtoBuf.JvmMethodSignature?
-        ): JvmProtoBuf.JvmPropertySignature {
+        ): JvmProtoBuf.JvmPropertySignature? {
             val signature = JvmProtoBuf.JvmPropertySignature.newBuilder()
 
             if (fieldDesc != null) {
@@ -281,7 +283,7 @@ class JvmSerializerExtension(private val bindings: JvmSerializationBindings, sta
                 signature.setter = setter
             }
 
-            return signature.build()
+            return signature.build().takeIf { it.serializedSize > 0 }
         }
 
         fun fieldSignature(

libraries/tools/kotlinp/testData/Annotations.txt

@@ -5,83 +5,63 @@ public final annotation class A : kotlin/Annotation {
   // signature: <init>(ZCBSIFJD[Z[C[B[S[I[F[J[DLjava/lang/String;Lkotlin/annotation/AnnotationTarget;Lkotlin/reflect/KClass;LB;)V
   public /* primary */ constructor(z: kotlin/Boolean, c: kotlin/Char, b: kotlin/Byte, s: kotlin/Short, i: kotlin/Int, f: kotlin/Float, j: kotlin/Long, d: kotlin/Double, za: kotlin/BooleanArray, ca: kotlin/CharArray, ba: kotlin/ByteArray, sa: kotlin/ShortArray, ia: kotlin/IntArray, fa: kotlin/FloatArray, ja: kotlin/LongArray, da: kotlin/DoubleArray, str: kotlin/String, enum: kotlin/annotation/AnnotationTarget, klass: kotlin/reflect/KClass<*>, anno: B)
 
-  // field: anno:LB;
   public final val anno: B
     public final get
 
-  // field: b:B
   public final val b: kotlin/Byte
     public final get
 
-  // field: ba:[B
   public final val ba: kotlin/ByteArray
     public final get
 
-  // field: c:C
   public final val c: kotlin/Char
     public final get
 
-  // field: ca:[C
   public final val ca: kotlin/CharArray
     public final get
 
-  // field: d:D
   public final val d: kotlin/Double
     public final get
 
-  // field: da:[D
   public final val da: kotlin/DoubleArray
     public final get
 
-  // field: enum:Lkotlin/annotation/AnnotationTarget;
   public final val enum: kotlin/annotation/AnnotationTarget
     public final get
 
-  // field: f:F
   public final val f: kotlin/Float
     public final get
 
-  // field: fa:[F
   public final val fa: kotlin/FloatArray
     public final get
 
-  // field: i:I
   public final val i: kotlin/Int
     public final get
 
-  // field: ia:[I
   public final val ia: kotlin/IntArray
     public final get
 
-  // field: j:J
   public final val j: kotlin/Long
     public final get
 
-  // field: ja:[J
   public final val ja: kotlin/LongArray
     public final get
 
-  // field: klass:Lkotlin/reflect/KClass;
   public final val klass: kotlin/reflect/KClass<*>
     public final get
 
-  // field: s:S
   public final val s: kotlin/Short
     public final get
 
-  // field: sa:[S
   public final val sa: kotlin/ShortArray
     public final get
 
-  // field: str:Ljava/lang/String;
   public final val str: kotlin/String
     public final get
 
-  // field: z:Z
   public final val z: kotlin/Boolean
     public final get
 
-  // field: za:[Z
   public final val za: kotlin/BooleanArray
     public final get
 }
@@ -92,7 +72,6 @@ public final annotation class B : kotlin/Annotation {
   // signature: <init>(Ljava/lang/String;)V
   public /* primary */ constructor(value: kotlin/String)
 
-  // field: value:Ljava/lang/String;
   public final val value: kotlin/String
     public final get
 }

libraries/tools/kotlinp/testData/LocalDelegatedProperties.txt

@@ -9,17 +9,14 @@ public final class Class : kotlin/Any {
   public final fun f(): kotlin/Unit
 
   // local delegated property #0
-  // field: local4:Lkotlin/Array;
   // local final /* delegated */ val local4: kotlin/Array<kotlin/String>
   //   local final get
 
   // local delegated property #1
-  // field: local5:Ljava/util/List;
   // local final /* delegated */ val local5: kotlin/collections/List<kotlin/Unit>?
   //   local final get
 
   // local delegated property #2
-  // field: local6:I
   // local final /* delegated */ val local6: kotlin/Int
   //   local final get
 }
@@ -65,17 +62,14 @@ package {
     public final /* non-default */ get
 
   // local delegated property #0
-  // field: local1:D
   // local final /* delegated */ val local1: kotlin/Double
   //   local final get
 
   // local delegated property #1
-  // field: local2:Ljava/lang/Object;
   // local final /* delegated */ val local2: kotlin/Any
   //   local final get
 
   // local delegated property #2
-  // field: local3:Ljava/lang/CharSequence;
   // local final /* delegated */ val local3: kotlin/CharSequence?
   //   local final get
 }