[visitor-plugin-common] fix: keep local fragment definition over its external copy (#10932)

.changeset/local-fragment-over-external.md

@@ -0,0 +1,5 @@
+---
+'@graphql-codegen/visitor-plugin-common': patch
+---
+
+Keep the local definition of a fragment when the same fragment is also passed as an external fragment, so its `*FragmentDoc` is generated again. This fixes `near-operation-file` output for a fragment declared in one `gql` tag and spread by an operation in another `gql` tag of the same file.

packages/plugins/other/visitor-plugin-common/src/client-side-base-visitor.ts

@@ -284,7 +284,18 @@ export class ClientSideBaseVisitor<
     this._documents = documents;
     this._onExecutableDocumentNode = (rawConfig as any).unstable_onExecutableDocumentNode;
     this._omitDefinitions = (rawConfig as any).unstable_omitDefinitions;
-    this._fragments = new Map(fragments.map(fragment => [fragment.name, fragment]));
+    const fragmentsByName = new Map<string, LoadedFragment>();
+    for (const fragment of fragments) {
+      // A fragment can be passed both as a local definition and as an external one, e.g. when
+      // near-operation-file reports a fragment generated into the same file as external.
+      // Keep the local definition so its document is still generated.
+      const existing = fragmentsByName.get(fragment.name);
+      if (existing && !existing.isExternal && fragment.isExternal) {
+        continue;
+      }
+      fragmentsByName.set(fragment.name, fragment);
+    }
+    this._fragments = fragmentsByName;
     this.fragmentsGraph = this._getFragmentsGraph();
     autoBind(this);
   }

packages/plugins/other/visitor-plugin-common/tests/client-side-base-visitor.spec.ts

@@ -470,3 +470,46 @@ describe('includeExternalFragments', () => {
     expect(visitor.fragments).toContain('ExternalAFragment');
   });
 });
+
+describe('fragments declared locally and passed as external', () => {
+  const schema = buildSchema(/* GraphQL */ `
+    type Query {
+      user: User
+    }
+
+    type User {
+      id: ID!
+      name: String
+    }
+  `);
+
+  const toLoadedFragments = (source: string, isExternal: boolean) =>
+    parse(source)
+      .definitions.filter(d => d.kind === Kind.FRAGMENT_DEFINITION)
+      .map(fragmentDef => ({
+        node: fragmentDef,
+        name: fragmentDef.name.value,
+        onType: fragmentDef.typeCondition.name.value,
+        isExternal,
+      }));
+
+  const userFields = /* GraphQL */ `
+    fragment UserFields on User {
+      id
+      name
+    }
+  `;
+
+  // near-operation-file also reports fragments generated into the same file as external,
+  // so the same fragment reaches the visitor once as local and once as external.
+  it('should generate the FragmentDoc of the local definition', () => {
+    const visitor = new ClientSideBaseVisitor(
+      schema,
+      [...toLoadedFragments(userFields, false), ...toLoadedFragments(userFields, true)],
+      {},
+      {},
+    );
+
+    expect(visitor.fragments).toContain('export const UserFieldsFragmentDoc');
+  });
+});