#2794 is bug

[it512]

#2794
no ... I think this is bug....

uuid is value type , like int.
default value is zero value ( uuid.Nil), in GraphQL is UUID!
nil ('null") is *uuid.UUID in Graphql is UUID. ( no !)

so this is bug!

@StevenACoffman @0x221A

Originally posted by @it512 in #2794 (comment)

[it512]

@StevenACoffman

[it512]

type Todo {                                                                                                           
      id: ID!                                                                                                             
      text: String!                                                                                                       
       done: Boolean!                                                                                                      
       uid: UUID!                                                                                                          
       puid:UUID                                                                                                           
  }                                                                                                                     
 
type Query {                                                                                                          
   todos: [Todo!]!                                                                                                     
}       

---

{
  todos{
    uid
    puid
  }
}

go code

func (r *queryResolver) Todos(ctx context.Context) ([]*model.Todo, error) {                                           
   return []*model.Todo{                                                                                             
      {ID: "1", Text: "hello", Done: true, UID: uuid.New(), Puid: &uuid.UUID{}},                                    
     {ID: "2", Text: "world", Done: false, UID: uuid.New(), Puid: nil},                                            
    }, nil                                                                                                            
}                                                                                                                     

#2794 return

{
  "data": {
    "todos": [
      {
        "uid": "2156c78b-fa83-4ee7-ab24-5a871a433e85",
        "puid": null ---------------  &uuid.UUID{} is zero value (00000000-0000-0000-0000-000000000000) *** bug!!! ***
      },
      {
        "uid": "ff8b4cf9-db3a-4634-842f-a9394afa590d",
        "puid": null
      }
  }

ok result (v v0.17.37 )

{
  "data": {
    "todos": [
      {
        "uid": "0171dcab-6c95-4d1f-ac4a-a6a0f72d869b",
        "puid": "00000000-0000-0000-0000-000000000000" ---- zero value ok !!!
      },
      {
        "uid": "437e9668-ff9e-421d-b7d4-323dfbe2e244",
        "puid": null -------------- *uuid.UUID set to nil return null is ok (v0.17.37  is ok!!!)
      }
    ]
  }
}

[it512]

if need I can commit PR to fix #2794
@StevenACoffman

[StevenACoffman]

@0x221A Can you please comment on this?

[0x221A]

@StevenACoffman For me the user wants to return a zero value uuid instead of null for some reason then I will suggest using the custom mapping. Returning null first is the best way unless the user knows what they're dealing with. What u think?

[0x221A]

Using the pointer of uuid is the other approach but I'm concerned when using it with SQL scan interface or an unexpected nil address panic.

[it512]

show your code, let me see see.

[it512]

@0x221A look this
https://github.com/google/uuid/blob/v1.3.1/sql.go#L15

func (uuid *UUID) Scan(src interface{}) error {
	switch src := src.(type) {
	case nil:
		return nil // look this

	case string:
		// if an empty UUID comes from a table, we return a null UUID
		if src == "" {
			return nil
		}

		// see Parse for required string format
		u, err := Parse(src)
		if err != nil {
			return fmt.Errorf("Scan: %v", err)
		}

		*uuid = u

	case []byte:
		// if an empty UUID comes from a table, we return a null UUID
		if len(src) == 0 {
			return nil
		}

		// assumes a simple slice of bytes if 16 bytes
		// otherwise attempts to parse
		if len(src) != 16 {
			return uuid.Scan(string(src))
		}
		copy((*uuid)[:], src)

	default:
		return fmt.Errorf("Scan: unable to scan type %T into UUID", src)
	}

	return nil
}