From 88ba4b12b69e3c64fc1bc82fef2a38108e697e81 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Mon, 4 Sep 2023 14:25:00 +0300
Subject: [PATCH] Add list support to pblite deserializer

---
 libgm/pblite/deserialize.go | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/libgm/pblite/deserialize.go b/libgm/pblite/deserialize.go
index df986ef..a568246 100644
--- a/libgm/pblite/deserialize.go
+++ b/libgm/pblite/deserialize.go
@@ -21,11 +21,27 @@ func Unmarshal(data []byte, m proto.Message) error {
 	return deserializeFromSlice(anyDataArr, m.ProtoReflect())
 }
 
-func deserializeOne(val any, index int, ref protoreflect.Message, fieldDescriptor protoreflect.FieldDescriptor) (protoreflect.Value, error) {
+func deserializeOne(val any, index int, ref protoreflect.Message, insideList protoreflect.List, fieldDescriptor protoreflect.FieldDescriptor) (protoreflect.Value, error) {
 	var num float64
 	var expectedKind, str string
 	var boolean, ok bool
 	var outputVal protoreflect.Value
+	if fieldDescriptor.IsList() && insideList == nil {
+		nestedData, ok := val.([]any)
+		if !ok {
+			return outputVal, fmt.Errorf("expected untyped array at index %d for repeated field %s, got %T", index, fieldDescriptor.FullName(), val)
+		}
+		list := ref.NewField(fieldDescriptor).List()
+		list.NewElement()
+		for i, nestedVal := range nestedData {
+			nestedParsed, err := deserializeOne(nestedVal, i, ref, list, fieldDescriptor)
+			if err != nil {
+				return outputVal, err
+			}
+			list.Append(nestedParsed)
+		}
+		return protoreflect.ValueOfList(list), nil
+	}
 	switch fieldDescriptor.Kind() {
 	case protoreflect.MessageKind:
 		ok = true
@@ -33,7 +49,12 @@ func deserializeOne(val any, index int, ref protoreflect.Message, fieldDescripto
 		if !ok {
 			return outputVal, fmt.Errorf("expected untyped array at index %d for field %s, got %T", index, fieldDescriptor.FullName(), val)
 		}
-		nestedMessage := ref.NewField(fieldDescriptor).Message()
+		var nestedMessage protoreflect.Message
+		if insideList != nil {
+			nestedMessage = insideList.NewElement().Message()
+		} else {
+			nestedMessage = ref.NewField(fieldDescriptor).Message()
+		}
 		if err := deserializeFromSlice(nestedData, nestedMessage); err != nil {
 			return outputVal, err
 		}
@@ -104,7 +125,7 @@ func deserializeFromSlice(data []any, ref protoreflect.Message) error {
 		}
 
 		val := data[index]
-		outputVal, err := deserializeOne(val, index, ref, fieldDescriptor)
+		outputVal, err := deserializeOne(val, index, ref, nil, fieldDescriptor)
 		if err != nil {
 			return err
 		}