Fix JSON marshalling of an ID to be null (stop using unnecessary pointer)

[taimoorgit]

Issues

Extracted from #356

TL;DR

The test expectation is wrong because we shouldn't be using a pointer receiver.

Explanation

These changes in the test expectation is justified. The test expectations before were incorrect.

type IDTester struct {
	Key1 ol.ID  `json:"key1"`
	Key2 ol.ID  `json:"key2,omitempty"`
	Key3 *ol.ID `json:"key3"`
	Key4 *ol.ID `json:"key4,omitempty"`
}

func TestMarshalID(t *testing.T) {
	// Arrange
	id1 := ol.NewID() <------ we're getting a pointer to a blank ID (string)
	id2 := ol.NewID("Z2lkOi8vMTIzNDU2Nzg5")
	case1 := IDTester{}
	case2 := IDTester{
		Key1: *id1, <------ this is now a concrete empty ID (""). key1 is not omit empty, so it should serialize to null.
		Key2: *id1,
		Key3: id1,
		Key4: id1,
	}
	case3 := IDTester{
		Key1: *id2, <------ empty ID (""). again, key 1 is not omit empty, so it should serialize to null.
		Key2: *id2,
		Key3: id2,
		Key4: id2,
	}
	// Act
	buf1, err1 := json.Marshal(case1)
	buf2, err2 := json.Marshal(case2)
	buf3, err3 := json.Marshal(case3)
	// Assert
	autopilot.Ok(t, err1)
	autopilot.Equals(t, `{"key1":null,"key3":null}`, string(buf1))
	autopilot.Ok(t, err2)
	autopilot.Equals(t, `{"key1":null,"key3":null,"key4":null}`, string(buf2))

Changelog

• Stop using unnecessary pointer
• Fix test accordingly
• Make a changie entry

[rocktavious]

null for IDs means "unset" in our API generally but what does "" mean (for create and update mutations)? I'm concerned we are losing the ability to to create input types where "" is the expected JSON for input variables.

What is the underlying impetus for this change? golang has the ability to put functions on pointers or value types - theres no reason that I see restricting this.