encoding/json: ignores omitempty when multiple parameters used

[GPHofficial]

It's supposed to prioritize omitempty before the string type. Instead, it prioritizes string and attempts to parse the value regardless of whether an empty value

https://play.golang.org/p/Mq2eW3IR0A

[joeshaw]

omitempty only applies to JSON encoding, not decoding. (That appears to also be the case with encoding/asn1 and encoding/xml)

Go's encoding of that zero-value struct with omitempty is {}. If the Id field still had string set but not omitempty, it encodes as {"id": "0"}. It properly decodes both of those cases.

I'm not sure it's the correct thing to interpret "" as "0" for string-encoded integer fields. I know Go allows for this kind of encoding for 64-bit integers for safety (because JS only has 53-bit integer precision, IIRC), but is it a reasonably well specified practice? It looks like it was introduced in https://golang.org/cl/4918051

[bradfitz]

Yeah, it looks like this is working as intended.