Wrong introspection schema response

[alexandrim0]

After upgrade to 1.6.0 codegen stop works and graphiql console also with error "Expected UUID! to be a GraphQL nullable type."
It generates field with nested "kind": "NON_NULL" like this:

            {
              "args": [
                {
                  "name": "id",
                  "type": {
                    "kind": "NON_NULL",
                    "name": null,
                    "ofType": {
                      "kind": "NON_NULL",
                      "name": null,
                      "ofType": {
                        "kind": "SCALAR",
                        "name": "UUID",
                        "ofType": null
                      }
                    }
                  },
                  "description": "The record's `id` value",
                  "defaultValue": null
                }
              ],
              "name": "accountByPk",
              "type": {
                "kind": "OBJECT",
                "name": "Account",
                "ofType": null
              },
              "description": "Retrieve a record of type `Account` by its primary key",
              "isDeprecated": false,
              "deprecationReason": null
            },

• PostgreSQL: 18
• pg_graphql commit ref: release 1.6.0

[imor]

@alexandrim0 there's a breaking change in this version as mentioned in the release notes: https://github.com/supabase/pg_graphql/releases/tag/v1.6.0

Breaking: disable introspection by default by @imor in #628. See Introspection section in the docs

You can read more about the change in the Integration sections on the Configuration and Security pages.

[alexandrim0]

I red this and set introspection enabled.
Piece of json you can see above is from introspection answer.
Did you want to say, this nested non null kind is okay?

[imor]

Ah you talking about the double wrapping of the UUID in NON_NULL. That is definitely a bug introduced in this commit. But I can't reproduce the error "Expected UUID! to be a GraphQL nullable type." in GraphiQL. Can you share which GraphiQL version are you using. Please also share exact SQL and GraphQL queries to reproduce.

[alexandrim0]

I use GraphiQL 5 and "get-graphql-schema" from Prisma (to convert GraphQL schema from JSON to SDL) which also failed after upgrade.
There is no additional SQL or GraphQL queries.
I belive that tools fails because of nested NON_NULL type.

I saw error I wrote above when GraphiQL trying to fetch schema.
So, this can be error interpretation from js library used by GraphiQL and get-graphql-schema but not from pg_graphql.

[imor]

@utkarash2991 would you have time to take a look at this one? We should fix it before launching 1.6.0 on the platform as it looks like a regression.

[utkarash2991]

Repro steps:

1. Verify pg_graphql version and reset schema comment to default

SELECT extname, extversion FROM pg_extension WHERE extname = 'pg_graphql';                                                                                                                                                                                                 
 extname    | extversion                                                                                                                                                                                                                                                   
------------+------------                                                                                                                                                                                                                                                
 pg_graphql | 1.6.0      
COMMENT ON SCHEMA public IS NULL;

2. Create a table with a UUID primary key

CREATE TABLE test_pk (                                                                                                                                                                                                                                                     
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),                                                                                                                                                                                                                       
    name TEXT
);  

3. Confirm introspection is disabled by default (NULL comment = disabled)

SELECT obj_description(oid, 'pg_namespace') FROM pg_namespace WHERE nspname = 'public';                                                                                                                                                                                  
 obj_description                                                                       
-----------------
                                                                                                                                                                                                                                                                           
(1 row)
SELECT graphql.resolve('{ __schema { queryType { name } } }');                                                                                                                                                                                                             
{"data": null, "errors": [{"message": "Unknown field \"__schema\" on type Query"}]} 

4. Enable introspection and confirm it works

COMMENT ON SCHEMA public IS e'@graphql({"introspection": true})';
SELECT graphql.resolve('{ __schema { queryType { name } } }');                                                                                                                                                                                                             
{"data": {"__schema": {"queryType": {"name": "Query"}}}}                      

5. Query argument types — observe double NON_NULL on test_pkByPk

postgres=# SELECT graphql.resolve($$                                                                                                                                                                                                                                                  
postgres$#   {                                                                                                                                                                                                                                                                          
postgres$#     __schema {
postgres$#       queryType {                                                                                                                                                                                                                                                            
postgres$#         fields {                                                                                                                                                                                                                                                           
postgres$#           name  
postgres$#           args {
postgres$#             name
postgres$#             type { kind name ofType { kind name ofType { kind name } } }
postgres$#           }                                                             
postgres$#         }  
postgres$#       }  
postgres$#     }  
postgres$#   }
postgres$#   $$);
-[ RECORD 1 ]---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
resolve | {"data": {"__schema": {"queryType": {"fields": [{"args": [{"name": "nodeId", "type": {"kind": "NON_NULL", "name": null, "ofType": {"kind": "SCALAR", "name": "ID", "ofType": null}}}], "name": "node"}, {"args": [{"name": "id", "type": {"kind": "NON_NULL", "name": null, "ofType": {"kind": "NON_NULL", "name": null, "ofType": {"kind": "SCALAR", "name": "UUID"}}}}], "name": "test_pkByPk"}, {"args": [{"name": "first", "type": {"kind": "SCALAR", "name": "Int", "ofType": null}}, {"name": "last", "type": {"kind": "SCALAR", "name": "Int", "ofType": null}}, {"name": "before", "type": {"kind": "SCALAR", "name": "Cursor", "ofType": null}}, {"name": "after", "type": {"kind": "SCALAR", "name": "Cursor", "ofType": null}}, {"name": "offset", "type": {"kind": "SCALAR", "name": "Int", "ofType": null}}, {"name": "filter", "type": {"kind": "INPUT_OBJECT", "name": "test_pkFilter", "ofType": null}}, {"name": "orderBy", "type": {"kind": "LIST", "name": null, "ofType": {"kind": "NON_NULL", "name": null, "ofType": {"kind": "INPUT_OBJECT", "name": "test_pkOrderBy"}}}}], "name": "test_pkCollection"}]}}}}  

Issue:
The id argument has NON_NULL → NON_NULL → SCALAR (UUID). Compare with the correct node field which shows NON_NULL → SCALAR (ID).

Expected: NON_NULL → SCALAR (UUID) — a single non-null wrapper, per GraphQL spec (a Non‐Null type cannot wrap another Non‐Null type)

[utkarash2991]

Fix PR here : #635 . @olirice @imor can you please help reviewing this one?
@alexandrim0 can you please check once that the fix works for you . Thanks