reused

Author: thomasheyenbrock

src/type/__tests__/validation-test.ts

@@ -341,6 +341,12 @@ describe('Type System: A Schema must have Object root types', () => {
       input SomeInputObject {
         test: String
       }
+      input SomeInputObject2 {
+        test: String
+      }
+      input SomeInputObject3 {
+        test: String
+      }
     `);
 
     schema = extendSchema(
@@ -356,7 +362,7 @@ describe('Type System: A Schema must have Object root types', () => {
       schema,
       parse(`
         extend schema {
-          mutation: SomeInputObject
+          mutation: SomeInputObject2
         }
       `),
     );
@@ -365,7 +371,7 @@ describe('Type System: A Schema must have Object root types', () => {
       schema,
       parse(`
         extend schema {
-          subscription: SomeInputObject
+          subscription: SomeInputObject3
         }
       `),
     );
@@ -378,12 +384,12 @@ describe('Type System: A Schema must have Object root types', () => {
       },
       {
         message:
-          'Mutation root type must be Object type if provided, it cannot be SomeInputObject.',
+          'Mutation root type must be Object type if provided, it cannot be SomeInputObject2.',
         locations: [{ line: 3, column: 21 }],
       },
       {
         message:
-          'Subscription root type must be Object type if provided, it cannot be SomeInputObject.',
+          'Subscription root type must be Object type if provided, it cannot be SomeInputObject3.',
         locations: [{ line: 3, column: 25 }],
       },
     ]);
@@ -427,6 +433,73 @@ describe('Type System: A Schema must have Object root types', () => {
   });
 });
 
+describe('Type System: Root types must all be different if provided', () => {
+  it('rejects a Schema where the same type is used for the "query" and "mutation" root types', () => {
+    const schema = buildSchema(`
+      type SomeObject {
+        f: SomeObject
+      }
+
+      schema {
+        query: SomeObject
+        mutation: SomeObject
+      }
+    `);
+    expectJSON(validateSchema(schema)).toDeepEqual([
+      {
+        message:
+          'All root types must be different, SomeObject is already used for "query" and cannot also be used for "mutation".',
+        locations: [{ line: 8, column: 19 }],
+      },
+    ]);
+  });
+
+  it('rejects a Schema where the same type is used for the "query" and "subscription" root types', () => {
+    const schema = buildSchema(`
+      type SomeObject {
+        f: SomeObject
+      }
+
+      schema {
+        query: SomeObject
+        subscription: SomeObject
+      }
+    `);
+    expectJSON(validateSchema(schema)).toDeepEqual([
+      {
+        message:
+          'All root types must be different, SomeObject is already used for "query" and cannot also be used for "subscription".',
+        locations: [{ line: 8, column: 23 }],
+      },
+    ]);
+  });
+
+  it('rejects a Schema where the same type is used for the "mutation" and "subscription" root types', () => {
+    const schema = buildSchema(`
+      type SomeObject {
+        f: SomeObject
+      }
+
+      type Query {
+        f: SomeObject
+      }
+
+      schema {
+        query: Query
+        mutation: SomeObject
+        subscription: SomeObject
+      }
+    `);
+    expectJSON(validateSchema(schema)).toDeepEqual([
+      {
+        message:
+          'All root types must be different, SomeObject is already used for "mutation" and cannot also be used for "subscription".',
+        locations: [{ line: 13, column: 23 }],
+      },
+    ]);
+  });
+});
+
 describe('Type System: Objects must have fields', () => {
   it('accepts an Object type with fields object', () => {
     const schema = buildSchema(`

src/type/validate.ts

@@ -144,6 +144,44 @@ function validateRootTypes(context: SchemaValidationContext): void {
         (subscriptionType as any).astNode,
     );
   }
+
+  if (queryType && mutationType && queryType.name === mutationType.name) {
+    context.reportError(
+      'All root types must be different, ' +
+        queryType.name +
+        ' is already used for "query" and cannot also be used for "mutation".',
+      getOperationTypeNode(schema, OperationTypeNode.MUTATION) ??
+        mutationType.astNode,
+    );
+  }
+
+  if (
+    queryType &&
+    subscriptionType &&
+    queryType.name === subscriptionType.name
+  ) {
+    context.reportError(
+      'All root types must be different, ' +
+        queryType.name +
+        ' is already used for "query" and cannot also be used for "subscription".',
+      getOperationTypeNode(schema, OperationTypeNode.SUBSCRIPTION) ??
+        subscriptionType.astNode,
+    );
+  }
+
+  if (
+    mutationType &&
+    subscriptionType &&
+    mutationType.name === subscriptionType.name
+  ) {
+    context.reportError(
+      'All root types must be different, ' +
+        mutationType.name +
+        ' is already used for "mutation" and cannot also be used for "subscription".',
+      getOperationTypeNode(schema, OperationTypeNode.SUBSCRIPTION) ??
+        subscriptionType.astNode,
+    );
+  }
 }
 
 function getOperationTypeNode(