Support repeated entries in byte arrays

wire-golden-files/src/main/java/com/squareup/wire/proto3/java/all_types/AllTypes.java

@@ -2910,15 +2910,15 @@ public AllTypes decode(ProtoReader reader) throws IOException {
             }
             break;
           }
-          case 17: builder.nested_message(NestedMessage.ADAPTER.decode(reader)); break;
-          case 18: builder.any(AnyMessage.ADAPTER.decode(reader)); break;
-          case 19: builder.duration(ProtoAdapter.DURATION.decode(reader)); break;
-          case 20: builder.struct(ProtoAdapter.STRUCT_MAP.decode(reader)); break;
-          case 21: builder.list_value(ProtoAdapter.STRUCT_LIST.decode(reader)); break;
-          case 22: builder.value(ProtoAdapter.STRUCT_VALUE.decode(reader)); break;
+          case 17: builder.nested_message(Internal.decodeMessageOrMerge(NestedMessage.ADAPTER, reader, builder.nested_message)); break;
+          case 18: builder.any(Internal.decodeMessageOrMerge(AnyMessage.ADAPTER, reader, builder.any)); break;
+          case 19: builder.duration(Internal.decodeMessageOrMerge(ProtoAdapter.DURATION, reader, builder.duration)); break;
+          case 20: builder.struct(Internal.decodeMessageOrMerge(ProtoAdapter.STRUCT_MAP, reader, builder.struct)); break;
+          case 21: builder.list_value(Internal.decodeMessageOrMerge(ProtoAdapter.STRUCT_LIST, reader, builder.list_value)); break;
+          case 22: builder.value(Internal.decodeMessageOrMerge(ProtoAdapter.STRUCT_VALUE, reader, builder.value)); break;
           case 23: builder.null_value((Void) ProtoAdapter.STRUCT_NULL.decode(reader)); break;
-          case 24: builder.empty(ProtoAdapter.EMPTY.decode(reader)); break;
-          case 25: builder.timestamp(ProtoAdapter.INSTANT.decode(reader)); break;
+          case 24: builder.empty(Internal.decodeMessageOrMerge(ProtoAdapter.EMPTY, reader, builder.empty)); break;
+          case 25: builder.timestamp(Internal.decodeMessageOrMerge(ProtoAdapter.INSTANT, reader, builder.timestamp)); break;
           case 101: builder.opt_int32(ProtoAdapter.INT32.decode(reader)); break;
           case 102: builder.opt_uint32(ProtoAdapter.UINT32.decode(reader)); break;
           case 103: builder.opt_sint32(ProtoAdapter.SINT32.decode(reader)); break;

wire-golden-files/src/main/kotlin/squareup/protos/opaque_types/OuterOpaqueType.kt

@@ -16,6 +16,7 @@ import com.squareup.wire.ReverseProtoWriter
 import com.squareup.wire.Syntax.PROTO_2
 import com.squareup.wire.WireField
 import com.squareup.wire.`internal`.JvmField
+import com.squareup.wire.`internal`.decodeMessageOrMerge
 import com.squareup.wire.`internal`.sanitize
 import kotlin.Any
 import kotlin.AssertionError
@@ -118,7 +119,7 @@ public class OuterOpaqueType(
         val unknownFields = reader.forEachTag { tag ->
           when (tag) {
             1 -> inner_opaque_type_1 = ProtoAdapter.BYTES.decode(reader)
-            2 -> inner_opaque_type_2 = InnerOpaqueType2.ADAPTER.decode(reader)
+            2 -> inner_opaque_type_2 = decodeMessageOrMerge(InnerOpaqueType2.ADAPTER, reader, inner_opaque_type_2)
             else -> reader.readUnknownField(tag)
           }
         }

wire-golden-files/src/main/kotlin/squareup/wire/alltypes/AllTypes.kt

@@ -25,6 +25,7 @@ import com.squareup.wire.`internal`.JvmStatic
 import com.squareup.wire.`internal`.JvmSynthetic
 import com.squareup.wire.`internal`.LongArrayList
 import com.squareup.wire.`internal`.checkElementsNotNull
+import com.squareup.wire.`internal`.decodeMessageOrMerge
 import com.squareup.wire.`internal`.decodePrimitive_double
 import com.squareup.wire.`internal`.decodePrimitive_fixed32
 import com.squareup.wire.`internal`.decodePrimitive_fixed64
@@ -3945,7 +3946,7 @@ public class AllTypes private constructor(
             } catch (e: ProtoAdapter.EnumConstantNotFoundException) {
               reader.addUnknownField(tag, FieldEncoding.VARINT, e.value.toLong())
             }
-            17 -> builder.opt_nested_message(NestedMessage.ADAPTER.decode(reader))
+            17 -> builder.opt_nested_message(decodeMessageOrMerge(NestedMessage.ADAPTER, reader, builder.opt_nested_message))
             101 -> builder.req_int32(ProtoAdapter.INT32.decode(reader))
             102 -> builder.req_uint32(ProtoAdapter.UINT32.decode(reader))
             103 -> builder.req_sint32(ProtoAdapter.SINT32.decode(reader))
@@ -3966,7 +3967,7 @@ public class AllTypes private constructor(
             } catch (e: ProtoAdapter.EnumConstantNotFoundException) {
               reader.addUnknownField(tag, FieldEncoding.VARINT, e.value.toLong())
             }
-            117 -> builder.req_nested_message(NestedMessage.ADAPTER.decode(reader))
+            117 -> builder.req_nested_message(decodeMessageOrMerge(NestedMessage.ADAPTER, reader, builder.req_nested_message))
             201 -> rep_int32.add(ProtoAdapter.INT32.decode(reader))
             202 -> rep_uint32.add(ProtoAdapter.UINT32.decode(reader))
             203 -> rep_sint32.add(ProtoAdapter.SINT32.decode(reader))
@@ -4239,7 +4240,7 @@ public class AllTypes private constructor(
             } catch (e: ProtoAdapter.EnumConstantNotFoundException) {
               reader.addUnknownField(tag, FieldEncoding.VARINT, e.value.toLong())
             }
-            1_017 -> builder.ext_opt_nested_message(NestedMessage.ADAPTER.decode(reader))
+            1_017 -> builder.ext_opt_nested_message(decodeMessageOrMerge(NestedMessage.ADAPTER, reader, builder.ext_opt_nested_message))
             1_101 -> ext_rep_int32.add(ProtoAdapter.INT32.decode(reader))
             1_102 -> ext_rep_uint32.add(ProtoAdapter.UINT32.decode(reader))
             1_103 -> ext_rep_sint32.add(ProtoAdapter.SINT32.decode(reader))

wire-golden-files/src/main/kotlin/squareup/wire/mutable/MutablePacket.kt

@@ -16,6 +16,7 @@ import com.squareup.wire.ReverseProtoWriter
 import com.squareup.wire.Syntax.PROTO_2
 import com.squareup.wire.WireField
 import com.squareup.wire.`internal`.JvmField
+import com.squareup.wire.`internal`.decodeMessageOrMerge
 import kotlin.Any
 import kotlin.Boolean
 import kotlin.Deprecated
@@ -110,7 +111,7 @@ public class MutablePacket(
         val payload = mutableListOf<MutablePayload>()
         val unknownFields = reader.forEachTag { tag ->
           when (tag) {
-            1 -> header_ = MutableHeader.ADAPTER.decode(reader)
+            1 -> header_ = decodeMessageOrMerge(MutableHeader.ADAPTER, reader, header_)
             2 -> payload.add(MutablePayload.ADAPTER.decode(reader))
             else -> reader.readUnknownField(tag)
           }

wire-java-generator/src/main/java/com/squareup/wire/java/JavaGenerator.java

@@ -1394,6 +1394,21 @@ private CodeBlock decodeAndAssign(Field field, NameAllocator nameAllocator, bool
       return useBuilder
           ? CodeBlock.of("builder.$L.putAll($L)", fieldName, decode)
           : CodeBlock.of("$L.putAll($L)", fieldName, decode);
+    } else if (schema.getType(field.getType()) instanceof MessageType && !field.isOneOf()) {
+      CodeBlock adapter = singleAdapterFor(field, nameAllocator);
+      return useBuilder
+          ? CodeBlock.of(
+              "builder.$L($T.decodeMessageOrMerge($L, reader, builder.$L))",
+              fieldName,
+              Internal.class,
+              adapter,
+              fieldName)
+          : CodeBlock.of(
+              "$L = $T.decodeMessageOrMerge($L, reader, $L)",
+              fieldName,
+              Internal.class,
+              adapter,
+              fieldName);
     } else {
       return useBuilder
           ? field.getType().equals(ProtoType.STRUCT_NULL)

wire-java-generator/src/test/java/com/squareup/wire/java/JavaGeneratorTest.java

@@ -285,7 +285,7 @@ public void generateAbstractAdapter() throws Exception {
                 + "    long token = reader.beginMessage();\n"
                 + "    for (int tag; (tag = reader.nextTag()) != -1;) {\n"
                 + "      switch (tag) {\n"
-                + "        case 1: field = Foo.ADAPTER.decode(reader); break;\n"
+                + "        case 1: field = Internal.decodeMessageOrMerge(Foo.ADAPTER, reader, field); break;\n"
                 + "        case 2: bars.putAll(barsAdapter().decode(reader)); break;\n"
                 + "        case 3: numbers.add(ProtoAdapter.INT32.decode(reader)); break;\n"
                 + "        case 4: {\n"

wire-kotlin-generator/src/main/java/com/squareup/wire/kotlin/KotlinGenerator.kt

@@ -2062,6 +2062,14 @@ class KotlinGenerator private constructor(
 
       field.isRepeated -> CodeBlock.of("%N.add(%L)", fieldName, decode)
       field.isMap -> CodeBlock.of("%N.putAll(%L)", fieldName, decode)
+      field.type!!.isMessage && !field.isOneOf -> {
+        val decodeMessageOrMerge = MemberName("com.squareup.wire.internal", "decodeMessageOrMerge")
+        if (buildersOnly) {
+          CodeBlock.of("builder.%N(%M(%L, reader, builder.%N))", fieldName, decodeMessageOrMerge, adapterName, fieldName)
+        } else {
+          CodeBlock.of("%N = %M(%L, reader, %N)", fieldName, decodeMessageOrMerge, adapterName, fieldName)
+        }
+      }
       else -> CodeBlock.of(if (buildersOnly) "builder.%N(%L)" else "%N·= %L", fieldName, decode)
     }
   }

wire-kotlin-generator/src/test/java/com/squareup/wire/kotlin/KotlinGeneratorTest.kt

@@ -1832,7 +1832,7 @@ class KotlinGeneratorTest {
         |        val unknownFields = reader.forEachTag { tag ->
         |          when (tag) {
         |            1 -> name = ProtoAdapter.STRING.decode(reader)
-        |            2 -> location = StringPointAdapter.INSTANCE.decode(reader)
+        |            2 -> location = decodeMessageOrMerge(StringPointAdapter.INSTANCE, reader, location)
         |            else -> reader.readUnknownField(tag)
         |          }
         |        }

wire-protoc-compatibility-tests/src/main/proto/squareup/proto2/java/interop/interop_test.proto

@@ -55,3 +55,11 @@ message InteropBoxOneOf {
     sint32 f = 6;
   }
 }
+
+message SubInteropRepeatedUint {
+  repeated uint32 repeated_values = 1 [packed = true];
+}
+
+message InteropRepeatedUint {
+  optional SubInteropRepeatedUint sub_message = 1;
+}

wire-protoc-compatibility-tests/src/main/proto/squareup/proto2/kotlin/interop/interop_test.proto

@@ -55,3 +55,12 @@ message InteropBoxOneOf {
     sint32 f = 6;
   }
 }
+
+message SubInteropRepeatedUint {
+  repeated uint32 repeated_values = 1 [packed = true];
+}
+
+message InteropRepeatedUint {
+  optional SubInteropRepeatedUint sub_message = 1;
+}
+

wire-protoc-compatibility-tests/src/test/java/com/squareup/wire/Proto2WireProtocCompatibilityTests.kt

@@ -27,6 +27,10 @@ import okio.ByteString.Companion.decodeHex
 import org.junit.Test
 import squareup.proto2.java.empty.EmptyLength as EmptyLengthJ
 import squareup.proto2.java.interop.InteropMessage as InteropMessageJ
+import squareup.proto2.java.interop.InteropRepeatedUint as InteropRepeatedUintJ2
+import squareup.proto2.java.interop.InteropTest.InteropRepeatedUint as InteropRepeatedUintP2
+import squareup.proto2.java.interop.InteropTest.SubInteropRepeatedUint as SubInteropRepeatedUintP2
+import squareup.proto2.java.interop.SubInteropRepeatedUint as SubInteropRepeatedUintJ2
 import squareup.proto2.java.interop.type.EnumProto2 as EnumProto2J
 import squareup.proto2.java.interop.type.MessageProto2 as MessageProto2J
 import squareup.proto2.kotlin.MapTypes
@@ -49,10 +53,12 @@ import squareup.proto2.kotlin.interop.InteropMessageOuterClass.extRepProto2Enum
 import squareup.proto2.kotlin.interop.InteropMessageOuterClass.extRepProto2Message
 import squareup.proto2.kotlin.interop.InteropMessageOuterClass.extRepProto3Enum
 import squareup.proto2.kotlin.interop.InteropMessageOuterClass.extRepProto3Message
+import squareup.proto2.kotlin.interop.InteropRepeatedUint as InteropRepeatedUintK2
 import squareup.proto2.kotlin.interop.Quilt
 import squareup.proto2.kotlin.interop.QuiltColor
 import squareup.proto2.kotlin.interop.QuiltContainer
 import squareup.proto2.kotlin.interop.RepeatedEnum
+import squareup.proto2.kotlin.interop.SubInteropRepeatedUint as SubInteropRepeatedUintK2
 import squareup.proto2.kotlin.interop.type.EnumProto2 as EnumProto2K
 import squareup.proto2.kotlin.interop.type.InteropTypes.EnumProto2
 import squareup.proto2.kotlin.interop.type.InteropTypes.MessageProto2
@@ -183,6 +189,35 @@ class Proto2WireProtocCompatibilityTests {
     assertThat(mapTypeWire.map_string_string[""]).isEqualTo("ed")
   }
 
+  @Test fun decodingRepeatedEntries() {
+    // ── 1 ┐
+    //      ├─ 1: 3
+    //      ╰- 1: 3
+    val byteArray = byteArrayOf(10, 3, 10, 1, 3, 10, 3, 10, 1, 3)
+    assertThat(InteropRepeatedUintP2.parseFrom(byteArray))
+      .isEqualTo(
+        InteropRepeatedUintP2.newBuilder()
+          .setSubMessage(
+            SubInteropRepeatedUintP2.newBuilder().addAllRepeatedValues(listOf(3, 3)).build(),
+          )
+          .build(),
+      )
+    assertThat(InteropRepeatedUintK2.ADAPTER.decode(byteArray)).isEqualTo(
+      InteropRepeatedUintK2.Builder()
+        .sub_message(
+          SubInteropRepeatedUintK2.Builder().repeated_values(listOf(3, 3)).build(),
+        )
+        .build(),
+    )
+    assertThat(InteropRepeatedUintJ2.ADAPTER.decode(byteArray)).isEqualTo(
+      InteropRepeatedUintJ2.Builder()
+        .sub_message(
+          SubInteropRepeatedUintJ2.Builder().repeated_values(listOf(3, 3)).build(),
+        )
+        .build(),
+    )
+  }
+
   /**
    * The TS-proto library encodes enums differently from Wire or Protoc. Protoc is fine with this,
    * but it causes Wire to crash. The fix is to make Wire accept this format also.

wire-runtime/src/commonMain/kotlin/com/squareup/wire/internal/Internal.kt

@@ -29,6 +29,7 @@ import com.squareup.wire.ProtoWriter
 import com.squareup.wire.ReverseProtoWriter
 import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName
+import okio.Buffer
 
 // Methods for generated code use only. Not subject to public API rules.
 
@@ -347,6 +348,29 @@ fun encodeArray_double(array: DoubleArray, writer: ReverseProtoWriter, tag: Int)
   }
 }
 
+/**
+ * Decodes a message from [reader], merging with [existing] if not null.
+ * Per the proto specification, when an embedded message field appears multiple times, the values
+ * are merged: repeated fields are concatenated, singular fields take the later value.
+ */
+fun <E> decodeMessageOrMerge(adapter: ProtoAdapter<E>, reader: ProtoReader, existing: E?): E {
+  if (existing == null) return adapter.decode(reader)
+  val bytes = reader.readBytes()
+  val buffer = Buffer()
+  adapter.encode(buffer, existing)
+  buffer.write(bytes)
+  return adapter.decode(buffer)
+}
+
+fun <E> decodeMessageOrMerge(adapter: ProtoAdapter<E>, reader: ProtoReader32, existing: E?): E {
+  if (existing == null) return adapter.decode(reader)
+  val bytes = reader.readBytes()
+  val buffer = Buffer()
+  adapter.encode(buffer, existing)
+  buffer.write(bytes)
+  return adapter.decode(buffer)
+}
+
 fun decodePrimitive_double(reader: ProtoReader32): Double = Double.fromBits(reader.readFixed64())
 fun decodePrimitive_double(reader: ProtoReader): Double = Double.fromBits(reader.readFixed64())
 fun decodePrimitive_fixed32(reader: ProtoReader32): Int = reader.readFixed32()