mergeFrom doesn't merge fields from other object

[mwildehahn]

https://github.com/alexeyxo/protobuf-swift/blob/master/src/compiler/swift_message.cc#L774-L776

given the function definition, i would expect this function to copy the fields for the "other" protobuf that is passed in.

why does it check if its the same class and then return itself? it should be the same class and then copy the attributes.

[alexeyxo]

If other is the default instance, we know none of its fields are set so we can skip the merge. This is small optimization.

[mwildehahn]

you can see above that its not merging the contents from the other protobuf because a populated protobuf is always equal to the default instance.

i removed the return statement in mergeFrom and it works properly.

[alexeyxo]

You are trying to merge two of the same objects other, this is not true.
In this case, the other object hasn't established fields.
You can merge other and user, because user has established field.
You can look implementation in C ++ / Java.

[mwildehahn]

sorry, i had a typo in there. this shows that other and user don't merge properly:

[mwildehahn]

because user == UserService.Containers.user() they don't merge.

[alexeyxo]

message Test
{
  optional string str = 11;
}

        var builder = Test.builder()
        builder.str = "123"
        println(builder)
        var build = builder.build()
        println(build)
        var builder2 = Test.builder()
        builder2.mergeFrom(build)
        var build2 = builder2.build()

        println(build2)
        println(build2 == build)
        println(build2 == Test.builder().build())
        println(build == Test.builder().build())
        println(build == Test())

Log:

 str: 123 

 str: 123 

 str: 123 

 str: 123 

true
false
false
false

All ok!!