Use parent type name on interface types without fragments (#10503)

Author: Georgegriff

.changeset/odd-crabs-grab.md

@@ -0,0 +1,5 @@
+---
+'@graphql-codegen/visitor-plugin-common': patch
+---
+
+Use parent type name on interface types without fragments

packages/plugins/other/visitor-plugin-common/src/selection-set-to-object.ts

@@ -958,7 +958,24 @@ export class SelectionSetToObject<Config extends ParsedDocumentsConfig = ParsedD
   protected buildParentFieldName(typeName: string, parentName: string): string {
     // queries/mutations/fragments are guaranteed to be unique type names,
     // so we can skip affixing the field names with typeName
-    return operationTypes.includes(typeName) ? parentName : `${parentName}_${typeName}`;
+    if (operationTypes.includes(typeName)) {
+      return parentName;
+    }
+
+    // When the parent schema type is an interface, use the interface name instead of the concrete type
+    // BUT only if we're not inside a fragment (fragments explicitly target specific types)
+    const schemaType = this._schema.getType(typeName);
+    const isInFragment = parentName.includes('Fragment');
+    if (
+      isObjectType(schemaType) &&
+      this._parentSchemaType &&
+      isInterfaceType(this._parentSchemaType) &&
+      !isInFragment
+    ) {
+      return `${parentName}_${this._parentSchemaType.name}`;
+    }
+
+    return `${parentName}_${typeName}`;
   }
 }
 

packages/plugins/typescript/operations/tests/extract-all-types.spec.ts

@@ -1462,4 +1462,97 @@ describe('extractAllFieldsToTypes: true', () => {
 
     await validate(content, config, complexTestSchemaWithUnionsAndInterfaces);
   });
+  it('should handle interfaces without fragments', async () => {
+    const nestedInterfacesSchema = buildSchema(/* GraphQL */ `
+      type Query {
+        animals: [Animal!]
+      }
+
+      interface Animal {
+        name: String!
+        owner: Person!
+      }
+
+      type Cat implements Animal {
+        name: String!
+        owner: Person!
+      }
+
+      type Dog implements Animal {
+        name: String!
+        owner: Person!
+      }
+
+      interface Person {
+        name: String!
+      }
+
+      type Trainer implements Person {
+        name: String!
+      }
+
+      type Veterinarian implements Person {
+        name: String!
+      }
+    `);
+
+    const nestedInterfacesQuery = parse(/* GraphQL */ `
+      query GetAnimals {
+        animals {
+          name
+          owner {
+            name
+          }
+        }
+      }
+    `);
+
+    const config: TypeScriptDocumentsPluginConfig = {
+      preResolveTypes: true,
+      extractAllFieldsToTypes: true,
+      nonOptionalTypename: true,
+      dedupeOperationSuffix: true,
+    };
+
+    const { content } = await plugin(
+      nestedInterfacesSchema,
+      [{ location: 'test-file.ts', document: nestedInterfacesQuery }],
+      config,
+      { outputFile: '' }
+    );
+
+    // Issue #10502: When nested interfaces have the same fields, extractAllFieldsToTypes
+    // We need to use the interface name for the nested type name.
+
+    expect(content).toMatchInlineSnapshot(`
+      "export type GetAnimalsQuery_animals_Animal_owner_Trainer = { __typename: 'Trainer', name: string };
+
+      export type GetAnimalsQuery_animals_Animal_owner_Veterinarian = { __typename: 'Veterinarian', name: string };
+
+      export type GetAnimalsQuery_animals_Animal_owner =
+        | GetAnimalsQuery_animals_Animal_owner_Trainer
+        | GetAnimalsQuery_animals_Animal_owner_Veterinarian
+      ;
+
+      export type GetAnimalsQuery_animals_Cat = { __typename: 'Cat', name: string, owner: GetAnimalsQuery_animals_Animal_owner };
+
+      export type GetAnimalsQuery_animals_Dog = { __typename: 'Dog', name: string, owner: GetAnimalsQuery_animals_Animal_owner };
+
+      export type GetAnimalsQuery_animals =
+        | GetAnimalsQuery_animals_Cat
+        | GetAnimalsQuery_animals_Dog
+      ;
+
+      export type GetAnimalsQuery_Query = { __typename: 'Query', animals?: Array<GetAnimalsQuery_animals> | null };
+
+
+      export type GetAnimalsQueryVariables = Exact<{ [key: string]: never; }>;
+
+
+      export type GetAnimalsQuery = GetAnimalsQuery_Query;
+      "
+    `);
+
+    await validate(content, config, nestedInterfacesSchema);
+  });
 });