fix: allow models without field declarations (#749)

Author: ymc9

packages/language/src/generated/grammar.ts

@@ -2060,7 +2060,7 @@ export const ZModelGrammar = (): Grammar => loadedZModelGrammar ?? (loadedZModel
                 }
               }
             ],
-            "cardinality": "+"
+            "cardinality": "*"
           },
           {
             "$type": "Keyword",

packages/language/src/zmodel.langium

@@ -186,7 +186,7 @@ DataModel:
     '{' (
         fields+=DataModelField
             | attributes+=DataModelAttribute
-        )+
+        )*
     '}';
 
 DataModelField:

packages/schema/tests/schema/abstract.test.ts

@@ -9,4 +9,23 @@ describe('Abstract Schema Tests', () => {
         });
         await loadModel(content);
     });
+
+    it('empty inheritance', async () => {
+        await loadModel(`
+        datasource db {
+            provider = 'postgresql'
+            url = env('DATABASE_URL')
+        }
+        
+        generator js {
+            provider = 'prisma-client-js'
+        }
+        
+        abstract model Base {
+            id Int @id @default(autoincrement())
+        }
+
+        model Foo extends Base {}
+        `);
+    });
 });