fix(delegate): null reference when reading an optional relation (#1491)

packages/runtime/src/enhancements/delegate.ts

@@ -1101,6 +1101,10 @@ export class DelegateProxyHandler extends DefaultPrismaProxyHandler {
     }
 
     private assembleUp(model: string, entity: any) {
+        if (!entity) {
+            return entity;
+        }
+
         const result: any = {};
         const base = this.getBaseModel(model);
 
@@ -1148,6 +1152,10 @@ export class DelegateProxyHandler extends DefaultPrismaProxyHandler {
     }
 
     private assembleDown(model: string, entity: any) {
+        if (!entity) {
+            return entity;
+        }
+
         const result: any = {};
         const modelInfo = getModelInfo(this.options.modelMeta, model, true);
 

tests/regression/tests/issue-1483.test.ts

@@ -0,0 +1,68 @@
+import { loadSchema } from '@zenstackhq/testtools';
+describe('issue 1483', () => {
+    it('regression', async () => {
+        const { enhance } = await loadSchema(
+            `
+            model User {
+                @@auth
+                id    String @id
+                edits Edit[]
+                @@allow('all', true)
+            }
+
+            model Entity {
+
+                id    String @id @default(cuid())
+                name  String
+                edits Edit[]
+
+                type  String
+                @@delegate(type)
+
+                @@allow('all', true)
+            }
+
+            model Person extends Entity {
+            }
+
+            model Edit {
+                id       String  @id @default(cuid())
+
+                authorId String?
+                author   User?   @relation(fields: [authorId], references: [id], onDelete: Cascade, onUpdate: NoAction)
+
+                entityId String
+                entity   Entity  @relation(fields: [entityId], references: [id], onDelete: Cascade, onUpdate: NoAction)
+
+                @@allow('all', true)
+            }
+            `
+        );
+
+        const db = enhance();
+        await db.edit.deleteMany({});
+        await db.person.deleteMany({});
+        await db.user.deleteMany({});
+
+        const person = await db.person.create({
+            data: {
+                name: 'test',
+            },
+        });
+
+        await db.edit.create({
+            data: {
+                entityId: person.id,
+            },
+        });
+
+        await expect(
+            db.edit.findMany({
+                include: {
+                    author: true,
+                    entity: true,
+                },
+            })
+        ).resolves.toHaveLength(1);
+    });
+});