From 91bedcd43bee86fe1b578d2f10790a4a9ac4f891 Mon Sep 17 00:00:00 2001
From: ymc9 <104139426+ymc9@users.noreply.github.com>
Date: Fri, 28 Feb 2025 14:09:39 -0800
Subject: [PATCH] fix(auth): refix issue #1997

fixes #2019
---
 packages/runtime/src/cross/model-meta.ts      |  3 +-
 .../src/enhancements/node/default-auth.ts     | 25 ++----
 tests/regression/tests/issue-2019.test.ts     | 87 +++++++++++++++++++
 3 files changed, 97 insertions(+), 18 deletions(-)
 create mode 100644 tests/regression/tests/issue-2019.test.ts

diff --git a/packages/runtime/src/cross/model-meta.ts b/packages/runtime/src/cross/model-meta.ts
index 3b27f1686..727038fd4 100644
--- a/packages/runtime/src/cross/model-meta.ts
+++ b/packages/runtime/src/cross/model-meta.ts
@@ -86,8 +86,7 @@ export type FieldInfo = {
     relationField?: string;
 
     /**
-     * Mapping from foreign key field names to relation field names.
-     * Only available on relation fields.
+     * Mapping from relation's pk to fk. Only available on relation fields.
      */
     foreignKeyMapping?: Record<string, string>;
 
diff --git a/packages/runtime/src/enhancements/node/default-auth.ts b/packages/runtime/src/enhancements/node/default-auth.ts
index f151d014f..8bdd76490 100644
--- a/packages/runtime/src/enhancements/node/default-auth.ts
+++ b/packages/runtime/src/enhancements/node/default-auth.ts
@@ -126,7 +126,7 @@ class DefaultAuthHandler extends DefaultPrismaProxyHandler {
                 return;
             }
 
-            if (context.field?.backLink && context.nestingPath.length > 1) {
+            if (context.field?.backLink) {
                 // if the fk field is in a creation context where its implied by the parent,
                 // we should not set the default value, e.g.:
                 //
@@ -134,23 +134,16 @@ class DefaultAuthHandler extends DefaultPrismaProxyHandler {
                 // parent.create({ data: { child: { create: {} } } })
                 // ```
                 //
-                // event if child's fk to parent has a default value, we should not set default
+                // even if child's fk to parent has a default value, we should not set default
                 // value here
 
-                // fetch parent model from the parent context
-                const parentModel = getModelInfo(
-                    this.options.modelMeta,
-                    context.nestingPath[context.nestingPath.length - 2].model
-                );
-
-                if (parentModel) {
-                    // get the opposite side of the relation for the current create context
-                    const oppositeRelationField = requireField(this.options.modelMeta, model, context.field.backLink);
-                    if (parentModel.name === oppositeRelationField.type) {
-                        // if the opposite side matches the parent model, it means we currently in a creation context
-                        // that implicitly sets this fk field
-                        return;
-                    }
+                // get the opposite side of the relation for the current create context
+                const oppositeRelationField = requireField(this.options.modelMeta, model, context.field.backLink);
+                if (
+                    oppositeRelationField.foreignKeyMapping &&
+                    Object.values(oppositeRelationField.foreignKeyMapping).includes(fieldInfo.name)
+                ) {
+                    return;
                 }
             }
 
diff --git a/tests/regression/tests/issue-2019.test.ts b/tests/regression/tests/issue-2019.test.ts
new file mode 100644
index 000000000..e5eea9254
--- /dev/null
+++ b/tests/regression/tests/issue-2019.test.ts
@@ -0,0 +1,87 @@
+import { loadSchema } from '@zenstackhq/testtools';
+
+describe('issue 2019', () => {
+    it('regression', async () => {
+        const { prisma, enhance } = await loadSchema(
+            `
+            model Tenant {
+                id      String    @id @default(uuid())
+
+                users   User[]
+                content Content[]
+            }
+
+            model User {
+                id       String          @id @default(uuid())
+                tenantId String          @default(auth().tenantId)
+                tenant   Tenant          @relation(fields: [tenantId], references: [id])
+                posts    Post[]
+                likes    PostUserLikes[]
+
+                @@allow('all', true)
+            }
+
+            model Content {
+                tenantId    String @default(auth().tenantId)
+                tenant      Tenant @relation(fields: [tenantId], references: [id])
+                id          String @id @default(uuid())
+                contentType String
+
+                @@delegate(contentType)
+                @@allow('all', true)
+            }
+
+            model Post extends Content {
+                author   User            @relation(fields: [authorId], references: [id])
+                authorId String          @default(auth().id)
+
+                comments Comment[]
+                likes    PostUserLikes[]
+
+                @@allow('all', true)
+            }
+
+            model PostUserLikes extends Content {
+                userId String
+                user   User   @relation(fields: [userId], references: [id])
+
+                postId String
+                post   Post   @relation(fields: [postId], references: [id])
+
+                @@unique([userId, postId])
+
+                @@allow('all', true)
+            }
+
+            model Comment extends Content {
+                postId String
+                post   Post   @relation(fields: [postId], references: [id])
+
+                @@allow('all', true)
+            }
+            `,
+            { logPrismaQuery: true }
+        );
+
+        const tenant = await prisma.tenant.create({ data: {} });
+        const user = await prisma.user.create({ data: { tenantId: tenant.id } });
+        const db = enhance({ id: user.id, tenantId: tenant.id });
+        const result = await db.post.create({
+            data: {
+                likes: {
+                    createMany: {
+                        data: [
+                            {
+                                userId: user.id,
+                            },
+                        ],
+                    },
+                },
+            },
+            include: {
+                likes: true,
+            },
+        });
+        expect(result.likes[0].tenantId).toBe(tenant.id);
+    });
+});