Methods that return nothing must contain result field

[oblique]

We were trying to call a method that returns nothing but the library that we use in the client rejects to deserialize the response.

After some investigation we found the following in JSON RPC 2.0 spec:

result
This member is REQUIRED on success.
This member MUST NOT exist if there was an error invoking the method.
The value of this member is determined by the method invoked on the Server.

error
This member is REQUIRED on error.
This member MUST NOT exist if there was no error triggered during invocation.
The value for this member MUST be an Object as defined in section 5.1.

So on success the result field must exists.

The following unit tests are wrong:

go-jsonrpc/rpc_test.go

Lines 130 to 133 in 17a3577

	t.Run("inc", tc(`{"jsonrpc": "2.0", "method": "SimpleServerHandler.Inc", "params": [], "id": 1}`, `{"jsonrpc":"2.0","id":1}`, 1, 200))
	t.Run("inc-null", tc(`{"jsonrpc": "2.0", "method": "SimpleServerHandler.Inc", "params": null, "id": 1}`, `{"jsonrpc":"2.0","id":1}`, 1, 200))
	t.Run("inc-noparam", tc(`{"jsonrpc": "2.0", "method": "SimpleServerHandler.Inc", "id": 2}`, `{"jsonrpc":"2.0","id":2}`, 1, 200))
	t.Run("add", tc(`{"jsonrpc": "2.0", "method": "SimpleServerHandler.Add", "params": [10], "id": 4}`, `{"jsonrpc":"2.0","id":4}`, 10, 200))

[oblique]

This is what other servers return on a successful call:

{
    "jsonrpc": "2.0",
    "result": null,
    "id": 1
}

[Wondertan]

@oblique, so to make this spec compliant, we would change unit tests to return "result": null, in the expected response, correct?

[zvolin]

yes