Merge extensions correctly

3 files changed, 14 insertions, 6 deletions

diff --git a/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs b/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
index 67fdf966..4206f261 100644
--- a/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
+++ b/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
@@ -3936,6 +3936,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
@@ -4273,6 +4274,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
@@ -4565,6 +4567,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
@@ -4839,6 +4842,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
@@ -5063,6 +5067,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
@@ -5287,6 +5292,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
@@ -5511,6 +5517,7 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         if (other.uninterpretedOption_.Count != 0) {
           base.AddRange(other.uninterpretedOption_, result.uninterpretedOption_);
         }
+          this.MergeExtensionFields(other);
         this.MergeUnknownFields(other.UnknownFields);
         return this;
       }
diff --git a/src/ProtocolBuffers/DynamicMessage.cs b/src/ProtocolBuffers/DynamicMessage.cs
index 812be1c8..b740013b 100644
--- a/src/ProtocolBuffers/DynamicMessage.cs
+++ b/src/ProtocolBuffers/DynamicMessage.cs
@@ -284,15 +284,12 @@ namespace Google.ProtocolBuffers {
           throw new ArgumentException("MergeFrom(IMessage) can only merge messages of the same type.");
         }
         fields.MergeFrom(other);
+        MergeUnknownFields(other.UnknownFields);
         return this;
       }
 
       public override Builder MergeFrom(DynamicMessage other) {
-        if (other.DescriptorForType != type) {
-          throw new ArgumentException("MergeFrom(IMessage) can only merge messages of the same type.");
-        }
-        fields.MergeFrom(other);
-        return this;
+        return MergeFrom((IMessage)other);
       }
 
       public override DynamicMessage Build() {
diff --git a/src/ProtocolBuffers/ExtendableBuilder.cs b/src/ProtocolBuffers/ExtendableBuilder.cs
index 7f4461cb..b88f2994 100644
--- a/src/ProtocolBuffers/ExtendableBuilder.cs
+++ b/src/ProtocolBuffers/ExtendableBuilder.cs
@@ -159,12 +159,16 @@ namespace Google.ProtocolBuffers {
     public override TBuilder AddRepeatedField(FieldDescriptor field, object value) {
       if (field.IsExtension) {
         ExtendableMessage<TMessage, TBuilder> message = MessageBeingBuilt;
-        message.VerifyContainingType(field); 
+        message.VerifyContainingType(field);
         message.Extensions.AddRepeatedField(field, value);
         return ThisBuilder;
       } else {
         return base.AddRepeatedField(field, value);
       }
     }
+
+    protected void MergeExtensionFields(ExtendableMessage<TMessage, TBuilder> other) {
+      MessageBeingBuilt.Extensions.MergeFrom(other.Extensions);
+    }
   }
 }