Parse extend schema correctly when root operations list is absent

.changeset/afraid-oranges-clean.md

@@ -0,0 +1,9 @@
+---
+'graphql-language-service': patch
+---
+
+fix: Correctly parse schema extensions with no root operations
+
+Previously, the parser gave schema extensions the same treatment as schema definitions. The requirements are slightly different, however, since a schema extension does not require a list of root operations according to the spec: https://spec.graphql.org/draft/#sec-Schema-Extension.
+
+The rule for parsing a schema extension is now distinct from schema definition, allowing the root operations list to be omitted.

packages/graphql-language-service/src/parser/Rules.ts

@@ -239,14 +239,8 @@ export const ParseRules: { [name: string]: ParseRule } = {
   Implements: [word('implements'), list('NamedType', p('&'))],
   DirectiveLocation: [name('string-2')],
   // GraphQL schema language
-  SchemaDef: [
-    word('schema'),
-    list('Directive'),
-    p('{'),
-    list('OperationTypeDef'),
-    p('}'),
-  ],
-
+  SchemaDef: [word('schema'), list('Directive'), 'OperationTypeDefs'],
+  OperationTypeDefs: [p('{'), list('OperationTypeDef'), p('}')],
   OperationTypeDef: [name('keyword'), p(':'), name('atom')],
   ScalarDef: [word('scalar'), name('atom'), list('Directive')],
   ObjectTypeDef: [
@@ -322,7 +316,11 @@ export const ParseRules: { [name: string]: ParseRule } = {
         return Kind.INPUT_OBJECT_TYPE_EXTENSION;
     }
   },
-  [Kind.SCHEMA_EXTENSION]: ['SchemaDef'],
+  [Kind.SCHEMA_EXTENSION]: [
+    word('schema'),
+    list('Directive'),
+    opt('OperationTypeDefs'),
+  ],
   [Kind.SCALAR_TYPE_EXTENSION]: ['ScalarDef'],
   [Kind.OBJECT_TYPE_EXTENSION]: ['ObjectTypeDef'],
   [Kind.INTERFACE_TYPE_EXTENSION]: ['InterfaceDef'],

packages/graphql-language-service/src/parser/__tests__/OnlineParser-test.ts

@@ -56,7 +56,7 @@ describe('onlineParser', () => {
       `);
 
       t.keyword('schema', { kind: 'SchemaDef' });
-      t.punctuation('{');
+      t.punctuation('{', { kind: 'OperationTypeDefs' });
 
       t.keyword('query', { kind: 'OperationTypeDef' });
       t.punctuation(':');
@@ -67,6 +67,71 @@ describe('onlineParser', () => {
       t.eol();
     });
 
+    it('parses schema extension bare', () => {
+      const { t } = getUtils(`
+        extend schema
+      `);
+
+      t.keyword('extend', { kind: 'ExtendDef' });
+      t.keyword('schema', { kind: 'SchemaExtension' });
+
+      t.eol();
+    });
+
+    it('parses schema extension with operation defs', () => {
+      const { t } = getUtils(`
+        extend schema {
+          query: SomeType
+        }
+      `);
+
+      t.keyword('extend', { kind: 'ExtendDef' });
+      t.keyword('schema', { kind: 'SchemaExtension' });
+      t.punctuation('{', { kind: 'OperationTypeDefs' });
+
+      t.keyword('query', { kind: 'OperationTypeDef' });
+      t.punctuation(':');
+      t.name('SomeType');
+
+      t.punctuation('}', { kind: 'Document' });
+
+      t.eol();
+    });
+
+    it('parses schema extension with directive applications', () => {
+      const { t } = getUtils(`
+        extend schema @someDirective
+      `);
+
+      t.keyword('extend', { kind: 'ExtendDef' });
+      t.keyword('schema', { kind: 'SchemaExtension' });
+      expectDirective({ t }, { name: 'someDirective' });
+
+      t.eol();
+    });
+
+    it('parses schema extension with directive applications without root operation definitions, followed by a type definition', () => {
+      const { t } = getUtils(`
+        extend schema @someDirective
+
+        type A { field: String }
+      `);
+
+      t.keyword('extend', { kind: 'ExtendDef' });
+      t.keyword('schema', { kind: 'SchemaExtension' });
+      expectDirective({ t }, { name: 'someDirective' });
+
+      t.keyword('type', { kind: 'ObjectTypeDef' });
+      t.name('A');
+      t.punctuation('{');
+      t.property('field', { kind: 'FieldDef' });
+      t.punctuation(':');
+      t.name('String', { kind: 'NamedType' });
+      t.punctuation('}', { kind: 'Document' });
+
+      t.eol();
+    });
+
     it('parses short query', () => {
       const { t } = getUtils(`
         {