title: Cannot return null for non-nullable field , Debugger dosen't show null
body: <p>I have this schema.graphql</p>
  <pre><code>### This file was generated by Nexus Schema
  ### Do not make changes to this file directly
  
  
  type AuthPayload {
    token: String!
    users: users!
  }
  
  scalar DateTime
  
  type Mutation {
    login(email: String, password: String): AuthPayload!
    signup(CREATED_BY: String, EMAIL: String, FIRST_NAME: String, IS_ACTIVE: Boolean, PASSWORD: String, USERNAME: String): AuthPayload!
  }
  
  type Query {
    me: users
  }
  
  type users {
    CREATED_BY: String!
    CREATED_ON: DateTime
    EMAIL: String!
    FIRST_NAME: String!
    id: Int!
    IS_ACTIVE: Boolean!
    LAST_NAME: String
    MODIFIED_BY: String
    MODIFIED_ON: DateTime
    ORGANIZATION_ID: String
    PASSWORD: String!
    PHONE: String
    USERNAME: String!
  }
  </code></pre>
  <p>mutations :-</p>
  <pre><code>const Mutation = mutationType({
    definition(t) {
      t.field('signup', {
        type: 'AuthPayload',
        args: {
          FIRST_NAME: stringArg({ nullable: true }),
          EMAIL: stringArg(),
          PASSWORD: stringArg(),
          IS_ACTIVE: booleanArg(),
          USERNAME: stringArg(),
          CREATED_BY: stringArg(),
        },
        resolve: async (parent, { FIRST_NAME, EMAIL, PASSWORD ,IS_ACTIVE ,USERNAME,CREATED_BY }, ctx) =&gt; {
          const hashedPassword = await hash(PASSWORD, 10)
  
           const user = await ctx.prisma.users.create({
            data: {
              FIRST_NAME,
              EMAIL,
              PASSWORD: hashedPassword,
              IS_ACTIVE,
              USERNAME,
              CREATED_BY
            },
          })
          return {
            token: sign({ userId: user.id }, APP_SECRET),
            user,
          }
        },
      })
  
      t.field('login', {
        type: 'AuthPayload',
        args: {
          email: stringArg(),
          password: stringArg(),
        },
        resolve: async (parent, { email, password }, context) =&gt; {
          const user = await context.prisma.users.findOne({
            where: {
              EMAIL : email,
            },
          })
          if (!user) {
            return new Error(`No user found for email: ${email}`)
          }
          const passwordValid = await compare(password, user.PASSWORD)
          if (!passwordValid) {
            return new Error('Invalid password')
          }
          const token = await sign({ userId: user.id }, APP_SECRET)
          return {
            token ,
            user,
          }
        },
      })
    },
  })
  </code></pre>
  <p>My problem is when i try to mutate the login method with token return value , it works perfectly and here is my mutation</p>
  <pre><code>mutation{
  login(email :&quot;dondala422@hotmail.com&quot; password :&quot;aa&quot;)
  {
    token
  }
  }
  </code></pre>
  <p>Response</p>
  <pre><code>{
    &quot;data&quot;: {
      &quot;login&quot;: {
        &quot;token&quot;: &quot;eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOjMyLCJpYXQiOjE1OTcxMDY0OTd9.d1Ra32ArCXumBfzg2vE1-xeea21cAkNwWBJPm3U3akM&quot;
      }
    }
  }
  </code></pre>
  <p>As shown . this works perfectly . now as mentioned the AuthPayload return the token and the users type
  when i try to mutate with user :-</p>
  <pre><code>mutation{
  login(email :&quot;dondala422@hotmail.com&quot; password :&quot;aa&quot;)
  {
    token
      users{
      USERNAME
      FIRST_NAME
    }
  }
  }
  </code></pre>
  <p>it gives me this error</p>
  <pre><code>{
    &quot;errors&quot;: [
      {
        &quot;message&quot;: &quot;Cannot return null for non-nullable field AuthPayload.users.&quot;,
        &quot;locations&quot;: [
          {
            &quot;line&quot;: 4,
            &quot;column&quot;: 5
          }
        ],
        &quot;path&quot;: [
          &quot;login&quot;,
          &quot;users&quot;
        ],
        &quot;extensions&quot;: {
          &quot;code&quot;: &quot;INTERNAL_SERVER_ERROR&quot;,
          &quot;exception&quot;: {
            &quot;stacktrace&quot;: [
              &quot;Error: Cannot return null for non-nullable field AuthPayload.users.&quot;,
              &quot;    at completeValue (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:595:13)&quot;,
              &quot;    at completeValueCatchingError (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:530:19)&quot;,
              &quot;    at resolveField (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:461:10)&quot;,
              &quot;    at executeFields (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:297:18)&quot;,
              &quot;    at collectAndExecuteSubfields (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:748:10)&quot;,
              &quot;    at completeObjectValue (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:738:10)&quot;,
              &quot;    at completeValue (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:626:12)&quot;,
              &quot;    at completeValue (C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:592:21)&quot;,
              &quot;    at C:\\Users\\donda\\Desktop\\New folder (3)\\prisma-examples\\javascript\\graphql-auth - Copy\\node_modules\\graphql\\execution\\execute.js:527:16&quot;
            ]
          }
        }
      }
    ],
    &quot;data&quot;: null
  }
  </code></pre>
  <p>i tried to attach the debugger to see where is the null occur
  and i didn't found any nullable values</p>
  <p>here is a picture of vscode before return value , the token and user object are defined
  <a href="https://i.stack.imgur.com/wMyor.png" rel="nofollow noreferrer">VSCode Debugger picture</a></p>