fix(delegate): simulate cascade delete (#2120)

Author: ymc9

packages/runtime/src/cross/model-meta.ts

@@ -20,6 +20,11 @@ export type RuntimeAttribute = {
  */
 export type FieldDefaultValueProvider = (userContext: unknown) => unknown;
 
+/**
+ * Action to take when the related model is deleted or updated
+ */
+export type RelationAction = 'Cascade' | 'Restrict' | 'NoAction' | 'SetNull' | 'SetDefault';
+
 /**
  * Runtime information of a data model field
  */
@@ -74,6 +79,16 @@ export type FieldInfo = {
      */
     isRelationOwner?: boolean;
 
+    /**
+     * Action to take when the related model is deleted.
+     */
+    onDeleteAction?: RelationAction;
+
+    /**
+     * Action to take when the related model is updated.
+     */
+    onUpdateAction?: RelationAction;
+
     /**
      * If the field is a foreign key field
      */

packages/runtime/src/enhancements/node/delegate.ts

@@ -1160,19 +1160,90 @@ export class DelegateProxyHandler extends DefaultPrismaProxyHandler {
         }
     }
 
-    private async doDelete(db: CrudContract, model: string, args: any): Promise<unknown> {
+    private async doDelete(db: CrudContract, model: string, args: any, readBack = true): Promise<unknown> {
         this.injectWhereHierarchy(model, args.where);
         await this.injectSelectIncludeHierarchy(model, args);
 
+        // read relation entities that need to be cascade deleted before deleting the main entity
+        const cascadeDeletes = await this.getRelationDelegateEntitiesForCascadeDelete(db, model, args.where);
+
+        let result: unknown = undefined;
+        if (cascadeDeletes.length > 0) {
+            // we'll need to do cascade deletes of relations, so first
+            // read the current entity before anything changes
+            if (readBack) {
+                result = await this.doFind(db, model, 'findUnique', args);
+            }
+
+            // process cascade deletes of relations, this ensure their delegate base
+            // entities are deleted as well
+            await Promise.all(
+                cascadeDeletes.map(({ model, entity }) => this.doDelete(db, model, { where: entity }, false))
+            );
+        }
+
         if (this.options.logPrismaQuery) {
             this.logger.info(`[delegate] \`delete\` ${this.getModelName(model)}: ${formatObject(args)}`);
         }
-        const result = await db[model].delete(args);
-        const idValues = this.queryUtils.getEntityIds(model, result);
+
+        const deleteResult = await db[model].delete(args);
+        if (!result) {
+            result = this.assembleHierarchy(model, deleteResult);
+        }
 
         // recursively delete base entities (they all have the same id values)
+        const idValues = this.queryUtils.getEntityIds(model, deleteResult);
         await this.deleteBaseRecursively(db, model, idValues);
-        return this.assembleHierarchy(model, result);
+
+        return result;
+    }
+
+    private async getRelationDelegateEntitiesForCascadeDelete(db: CrudContract, model: string, where: any) {
+        if (!where || Object.keys(where).length === 0) {
+            throw new Error('where clause is required for cascade delete');
+        }
+
+        const cascadeDeletes: Array<{ model: string; entity: any }> = [];
+        const fields = getFields(this.options.modelMeta, model);
+        if (fields) {
+            for (const fieldInfo of Object.values(fields)) {
+                if (!fieldInfo.isDataModel) {
+                    continue;
+                }
+
+                if (fieldInfo.isRelationOwner) {
+                    // this side of the relation owns the foreign key,
+                    // so it won't cause cascade delete to the other side
+                    continue;
+                }
+
+                if (fieldInfo.backLink) {
+                    // get the opposite side of the relation
+                    const backLinkField = this.queryUtils.getModelField(fieldInfo.type, fieldInfo.backLink);
+
+                    if (backLinkField?.isRelationOwner && this.isFieldCascadeDelete(backLinkField)) {
+                        // if the opposite side of the relation is to be cascade deleted,
+                        // recursively delete the delegate base entities
+                        const relationModel = getModelInfo(this.options.modelMeta, fieldInfo.type);
+                        if (relationModel?.baseTypes && relationModel.baseTypes.length > 0) {
+                            // the relation model has delegate base, cascade the delete to the base
+                            const relationEntities = await db[relationModel.name].findMany({
+                                where: { [backLinkField.name]: where },
+                                select: this.queryUtils.makeIdSelection(relationModel.name),
+                            });
+                            relationEntities.forEach((entity) => {
+                                cascadeDeletes.push({ model: fieldInfo.type, entity });
+                            });
+                        }
+                    }
+                }
+            }
+        }
+        return cascadeDeletes;
+    }
+
+    private isFieldCascadeDelete(fieldInfo: FieldInfo) {
+        return fieldInfo.onDeleteAction === 'Cascade';
     }
 
     // #endregion

packages/sdk/src/model-meta-generator.ts

@@ -311,6 +311,18 @@ function writeFields(
         isRelationOwner: true,`);
                 }
 
+                const onDeleteAction = getOnDeleteAction(dmField);
+                if (onDeleteAction) {
+                    writer.write(`
+        onDeleteAction: '${onDeleteAction}',`);
+                }
+
+                const onUpdateAction = getOnUpdateAction(dmField);
+                if (onUpdateAction) {
+                    writer.write(`
+        onUpdateAction: '${onUpdateAction}',`);
+                }
+
                 if (isForeignKeyField(dmField)) {
                     writer.write(`
         isForeignKey: true,`);
@@ -568,3 +580,25 @@ function writeShortNameMap(options: ModelMetaGeneratorOptions, writer: CodeWrite
         writer.write(',');
     }
 }
+
+function getOnDeleteAction(fieldInfo: DataModelField) {
+    const relationAttr = getAttribute(fieldInfo, '@relation');
+    if (relationAttr) {
+        const onDelete = getAttributeArg(relationAttr, 'onDelete');
+        if (onDelete && isEnumFieldReference(onDelete)) {
+            return onDelete.target.ref?.name;
+        }
+    }
+    return undefined;
+}
+
+function getOnUpdateAction(fieldInfo: DataModelField) {
+    const relationAttr = getAttribute(fieldInfo, '@relation');
+    if (relationAttr) {
+        const onUpdate = getAttributeArg(relationAttr, 'onUpdate');
+        if (onUpdate && isEnumFieldReference(onUpdate)) {
+            return onUpdate.target.ref?.name;
+        }
+    }
+    return undefined;
+}

tests/integration/tests/enhancements/with-delegate/enhanced-client.test.ts

@@ -1057,7 +1057,7 @@ describe('Polymorphism Test', () => {
         expect(created.duration).toBe(300);
     });
 
-    it('delete', async () => {
+    it('delete simple', async () => {
         let { db, user, video: ratedVideo } = await setup();
 
         let deleted = await db.ratedVideo.delete({
@@ -1106,6 +1106,55 @@ describe('Polymorphism Test', () => {
         await expect(db.asset.findUnique({ where: { id: ratedVideo.id } })).resolves.toBeNull();
     });
 
+    it('delete cascade', async () => {
+        const { prisma, enhance } = await loadSchema(
+            `
+    model Base {
+        id Int @id @default(autoincrement())
+        type String
+        @@delegate(type)
+    }
+
+    model List extends Base {
+        name String
+        items Item[]
+    }
+
+    model Item extends Base {
+        name String
+        list List @relation(fields: [listId], references: [id], onDelete: Cascade)
+        listId Int
+        content ItemContent?
+    }
+
+    model ItemContent extends Base {
+        name String
+        item Item @relation(fields: [itemId], references: [id], onDelete: Cascade)
+        itemId Int @unique
+    }
+`,
+            { enhancements: ['delegate'], logPrismaQuery: true }
+        );
+
+        const db = enhance();
+        await db.list.create({
+            data: {
+                id: 1,
+                name: 'list',
+                items: {
+                    create: [{ id: 2, name: 'item1', content: { create: { id: 3, name: 'content1' } } }],
+                },
+            },
+        });
+
+        const r = await db.list.delete({ where: { id: 1 }, include: { items: { include: { content: true } } } });
+        expect(r).toMatchObject({ items: [{ id: 2 }] });
+        await expect(db.item.findUnique({ where: { id: 2 } })).toResolveNull();
+        await expect(prisma.base.findUnique({ where: { id: 2 } })).toResolveNull();
+        await expect(db.itemContent.findUnique({ where: { id: 3 } })).toResolveNull();
+        await expect(prisma.base.findUnique({ where: { id: 3 } })).toResolveNull();
+    });
+
     it('deleteMany', async () => {
         const { enhance } = await loadSchema(schema, { enhancements: ['delegate'] });
         const db = enhance();