EncodeNested with custom keys

[3052]

I see this:

https://godocs.io/github.com/CrowdStrike/csproto#Encoder.EncodeNested

but its not clear what keys are being used. after some testing it seems the code just pick 1 and then 2, etc. is it possible to encode something like this with custom keys?

[dylan-bourque]

A nested message is encoded as a bytes field using whatever tag gets passed to EncodeNested. The tags for the fields within that nested message come from the message itself. The only thing that is hard-coded are the field tags for map elements, which are always 1 for the key and 2 for the value.

I'm not exactly sure what you're asking. Can you clarify?

[3052]

look at this:

csproto/encoder_test.go

Lines 759 to 767 in 5b2bf93

	var (
	name = "test"
	val int32 = 42
	expected = []byte{0xa, 0x8, 0xa, 0x4, 0x74, 0x65, 0x73, 0x74, 0x10, 0x2a}
	)
	m := testNestedMsg{
	Name: &name,
	Value: &val,
	}

no keys are explicitly given to the Name and Value fields, but if you decode the resulting bytes its discovered that 1 and 2 were used.

[dylan-bourque]

I see. That testNestedMsg type is a local "mock" specifically for those tests, not an actual protobuf message. The tags actually are hard-coded in testNestedMsg.MarshalTo() here. csproto.Marshal() will call that method, if it exists, passing in a pre-allocated buffer based on the value returned by the message's Size() method. In this case, I took advantage of that to not have to generate code from a .proto file for these tests.

For a real message, the tags would come from the field IDs in the .proto file.