fix: incorrect relation owner analysis

Should check if a `@relation` attribute really has `fields` argument to determine if it holds foreign key.

Author: ymc9

packages/schema/src/plugins/model-meta/index.ts

@@ -11,6 +11,7 @@ import type { RuntimeAttribute } from '@zenstackhq/runtime';
 import {
     createProject,
     emitProject,
+    getAttributeArg,
     getAttributeArgs,
     getDataModels,
     getLiteral,
@@ -182,14 +183,25 @@ function isRelationOwner(field: DataModelField, backLink: DataModelField | undef
         return false;
     }
 
-    if (hasAttribute(field, '@relation')) {
-        // this field has `@relation` attribute
+    if (!backLink) {
+        // CHECKME: can this really happen?
         return true;
-    } else if (!backLink || !hasAttribute(backLink, '@relation')) {
-        // if the opposite side field doesn't have `@relation` attribute either,
-        // it's an implicit many-to-many relation, both sides are owners
+    }
+
+    if (!hasAttribute(field, '@relation') && !hasAttribute(backLink, '@relation')) {
+        // if neither side has `@relation` attribute, it's an implicit many-to-many relation,
+        // both sides are owners
         return true;
-    } else {
+    }
+
+    return holdsForeignKey(field);
+}
+
+function holdsForeignKey(field: DataModelField) {
+    const relation = field.attributes.find((attr) => attr.decl.ref?.name === '@relation');
+    if (!relation) {
         return false;
     }
+    const fields = getAttributeArg(relation, 'fields');
+    return !!fields;
 }

tests/integration/tests/regression/issues.test.ts

@@ -300,4 +300,58 @@ describe('GitHub issues regression', () => {
             },
         });
     });
+
+    it('issue 609', async () => {
+        const { withPolicy, prisma } = await loadSchema(
+            `
+            model User {
+                id String @id @default(cuid())
+                comments Comment[]
+            }
+    
+            model Comment {
+                id                 String      @id @default(cuid())
+                parentCommentId    String? 
+                replies            Comment[]   @relation("CommentToComment")
+                parent             Comment?    @relation("CommentToComment", fields: [parentCommentId], references: [id])
+                comment            String
+                author             User        @relation(fields: [authorId], references: [id])
+                authorId           String      
+                
+                @@allow('read,create', true)
+                @@allow('update,delete', auth() == author)
+            }    
+            `
+        );
+
+        await prisma.user.create({
+            data: {
+                id: '1',
+                comments: {
+                    create: {
+                        id: '1',
+                        comment: 'Comment 1',
+                    },
+                },
+            },
+        });
+
+        await prisma.user.create({
+            data: {
+                id: '2',
+            },
+        });
+
+        // connecting a child comment from a different user to a parent comment should succeed
+        const db = withPolicy({ id: '2' });
+        await expect(
+            db.comment.create({
+                data: {
+                    comment: 'Comment 2',
+                    author: { connect: { id: '2' } },
+                    parent: { connect: { id: '1' } },
+                },
+            })
+        ).toResolveTruthy();
+    });
 });