@computed fields from mixin types (with) cause column does not exist error when the model is explicitly included

tests/e2e/orm/client-api/computed-field-nested-include.test.ts

@@ -0,0 +1,87 @@
+import { createTestClient } from '@zenstackhq/testtools';
+import { describe, expect, it } from 'vitest';
+
+// Bug: when a model with @computed fields inherited from a mixin type (the `with`
+// keyword) is fetched as a nested relation via an explicit `include`, ZenStack
+// emits the computed field name as a raw column reference inside `jsonb_build_object`
+// while the inner subquery SELECT only contains the real DB columns. This causes
+// PostgreSQL to fail with:
+//   "column $$tN.field_name does not exist"
+//
+// Root cause: `buildSelectField` uses `fieldDef.originModel` (the mixin type name)
+// as the table alias when selecting the computed field into the inner subquery.
+// But the inner subquery aliases the actual table under the model name, not the
+// mixin type name, so the correlated subquery is never emitted and `parentCode`
+// is absent from the subquery's SELECT list. The outer `jsonb_build_object` then
+// references `$$tN.parentCode` which does not exist.
+//
+// The bug does NOT occur when:
+//   - the @computed field is declared directly on the model (not via a mixin type)
+//   - the relation is not explicitly included
+//   - the model is queried directly (not as a nested include)
+
+describe('Computed fields with nested include', () => {
+    it('includes computed fields inherited from a mixin type when the model is explicitly included', async () => {
+        const db = await createTestClient(
+            `
+type ParentRelated {
+    parentCode String? @computed
+}
+
+model Parent {
+    id       Int     @id @default(autoincrement())
+    code     String
+    children Child[]
+}
+
+model Child with ParentRelated {
+    id       Int     @id @default(autoincrement())
+    name     String
+    parentId Int
+    parent   Parent  @relation(fields: [parentId], references: [id])
+}
+            `,
+            {
+                provider: 'postgresql',
+                computedFields: {
+                    Child: {
+                        // Correlated subquery — looks up Parent.code via the FK.
+                        // The computed field is inherited from the `ParentRelated` mixin,
+                        // so fieldDef.originModel === 'ParentRelated', which is the
+                        // alias incorrectly used by buildSelectField.
+                        parentCode: (eb: any) =>
+                            eb
+                                .selectFrom('Parent')
+                                .select('Parent.code')
+                                .whereRef('Parent.id', '=', 'parentId')
+                                .limit(1),
+                    },
+                },
+            } as any,
+        );
+
+        const parent = await db.parent.create({
+            data: { code: 'P-001', children: { create: [{ name: 'Alice' }, { name: 'Bob' }] } },
+        });
+
+        // Direct query on Child works fine
+        await expect(db.child.findFirst({ where: { parentId: parent.id } })).resolves.toMatchObject({
+            parentCode: 'P-001',
+        });
+
+        // Querying Parent with include: { children: true } should also work,
+        // but currently fails with "column $$tN.parentCode does not exist"
+        await expect(
+            db.parent.findFirst({
+                where: { id: parent.id },
+                include: { children: true },
+            }),
+        ).resolves.toMatchObject({
+            code: 'P-001',
+            children: expect.arrayContaining([
+                expect.objectContaining({ name: 'Alice', parentCode: 'P-001' }),
+                expect.objectContaining({ name: 'Bob', parentCode: 'P-001' }),
+            ]),
+        });
+    });
+});