fix(visitor-plugin-common): handles more cases in conditional spread of a fragment

.changeset/brown-books-build.md

@@ -0,0 +1,7 @@
+---
+'@graphql-codegen/visitor-plugin-common': patch
+'@graphql-codegen/typescript-operations': patch
+---
+
+handles conditional spread of a fragment whose top-level selections are fragment spreads or contain
+inline fragments

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

@@ -571,7 +571,36 @@ export class SelectionSetToObject<
               [],
             );
 
-            collectGrouped(flattenedSelectionNodes);
+            // Top-level INLINE_FRAGMENT / FRAGMENT_SPREAD nodes among the
+            // inlined selections cannot be consumed directly by
+            // `buildSelectionSet`, which only handles FIELD and DIRECTIVE
+            // kinds for AST nodes and throws "Unexpected type." otherwise.
+            // Route them through `flattenSelectionSet` — which already
+            // expands inline fragments and fragment spreads per type — and
+            // merge the FIELD-only result with the already-FIELD selections
+            // before handing off.
+            const directNodes: GroupedTypeNameNode[] = [];
+            const nestedSelections: SelectionNode[] = [];
+            for (const n of flattenedSelectionNodes) {
+              if (
+                'kind' in n &&
+                (n.kind === Kind.INLINE_FRAGMENT || n.kind === Kind.FRAGMENT_SPREAD)
+              ) {
+                nestedSelections.push(n);
+              } else {
+                directNodes.push(n);
+              }
+            }
+            if (nestedSelections.length) {
+              const { selectionNodesByTypeName: nestedByType } = this.flattenSelectionSet(
+                nestedSelections,
+                schemaType,
+              );
+              const nestedForThisType = nestedByType.get(typeName) ?? [];
+              directNodes.push(...nestedForThisType);
+            }
+
+            collectGrouped(directNodes);
           }
 
           if (incrementalDirectivesFound) {

packages/plugins/typescript/operations/tests/ts-documents.skip-include-directives.spec.ts

@@ -604,6 +604,125 @@ describe('TypeScript Operations Plugin - @include directives', () => {
       "
     `);
   });
+
+  it('handles conditional spread of a fragment whose top-level selections contain inline fragments', async () => {
+    // Regression: when the spread fragment's top-level selection set contains
+    // an INLINE_FRAGMENT (or nested FRAGMENT_SPREAD), the conditional path used
+    // to push those raw AST nodes into `buildSelectionSet`, which only accepts
+    // FIELD/DIRECTIVE for raw nodes and threw `TypeError: Unexpected type.`.
+    const testSchema = buildSchema(/* GraphQL */ `
+      type Book {
+        id: ID!
+        title: String!
+      }
+      type Magazine {
+        id: ID!
+        issue: Int!
+      }
+      union Publication = Book | Magazine
+      type Library {
+        id: ID!
+        name: String!
+        featured: Publication
+      }
+      type Query {
+        library(id: ID!): Library
+      }
+    `);
+
+    const document = parse(/* GraphQL */ `
+      fragment PublicationFragment on Publication {
+        ... on Book {
+          id
+          title
+        }
+        ... on Magazine {
+          id
+          issue
+        }
+      }
+
+      query Library($includeFeatured: Boolean!) {
+        library(id: "x") {
+          id
+          name
+          featured {
+            ...PublicationFragment @include(if: $includeFeatured)
+          }
+        }
+      }
+    `);
+
+    const { content } = await plugin(
+      testSchema,
+      [{ location: '', document }],
+      {},
+      { outputFile: 'graphql.ts' },
+    );
+
+    // Should not throw, and should produce a usable type where the Publication
+    // fields appear when includeFeatured=true and an empty-object variant
+    // covers includeFeatured=false.
+    expect(content).toContain('LibraryQuery');
+    expect(content).toContain('featured');
+  });
+
+  it('handles conditional spread of a fragment whose top-level selections are fragment spreads', async () => {
+    // Same regression, but the inline fragments inside the spread fragment have
+    // been refactored into named fragment spreads — also failed before the fix.
+    const testSchema = buildSchema(/* GraphQL */ `
+      type Book {
+        id: ID!
+        title: String!
+      }
+      type Magazine {
+        id: ID!
+        issue: Int!
+      }
+      union Publication = Book | Magazine
+      type Library {
+        id: ID!
+        featured: Publication
+      }
+      type Query {
+        library(id: ID!): Library
+      }
+    `);
+
+    const document = parse(/* GraphQL */ `
+      fragment BookFragment on Book {
+        id
+        title
+      }
+      fragment MagazineFragment on Magazine {
+        id
+        issue
+      }
+      fragment PublicationFragment on Publication {
+        ...BookFragment
+        ...MagazineFragment
+      }
+
+      query Library($includeFeatured: Boolean!) {
+        library(id: "x") {
+          id
+          featured {
+            ...PublicationFragment @include(if: $includeFeatured)
+          }
+        }
+      }
+    `);
+
+    const { content } = await plugin(
+      testSchema,
+      [{ location: '', document }],
+      {},
+      { outputFile: 'graphql.ts' },
+    );
+
+    expect(content).toContain('LibraryQuery');
+    expect(content).toContain('featured');
+  });
 });
 
 describe('TypeScript Operations Plugin - @skip directive', () => {