fix: Take into account parent's primaryColumn config when fetching from polymorphic child

Before, on a child repository's options, we didn't handle the case in which there were multiple parents which had different `primaryColumn` names

Now we take such configurations into account. Specifically, we fetch the metadata associated with the parent we are visiting and read its `primaryColumn`. This allows for multiple parents to have different ID names when such situations arise.

Author: danteBenitez

src/__tests__/entities/admin.entity.ts

@@ -0,0 +1,15 @@
+import { Entity, PrimaryGeneratedColumn } from 'typeorm';
+import { PolymorphicChildren } from '../../../dist';
+import { AdvertEntity } from './advert.entity';
+
+@Entity('admins')
+export class AdminEntity {
+    @PrimaryGeneratedColumn()
+    admin_id: number;
+
+    @PolymorphicChildren(() => AdvertEntity, {
+        eager: false,
+        primaryColumn: "admin_id"
+    })
+    adverts: AdvertEntity[];
+}

src/__tests__/entities/advert.entity.ts

@@ -1,5 +1,6 @@
 import { Column, Entity, PrimaryGeneratedColumn } from 'typeorm';
 import { PolymorphicParent } from '../../../dist';
+import { AdminEntity } from './admin.entity';
 import { MerchantEntity } from './merchant.entity';
 import { UserEntity } from './user.entity';
 
@@ -8,10 +9,10 @@ export class AdvertEntity {
   @PrimaryGeneratedColumn()
   id: number;
 
-  @PolymorphicParent(() => [UserEntity, MerchantEntity], {
+  @PolymorphicParent(() => [UserEntity, MerchantEntity, AdminEntity], {
     eager: true,
   })
-  owner: UserEntity | MerchantEntity;
+  owner: UserEntity | MerchantEntity | AdminEntity;
 
   @Column({ nullable: true })
   entityId: number;

src/__tests__/polymorphic.repository.spec.ts

@@ -1,11 +1,12 @@
-import { DataSource, Repository } from 'typeorm';
-import { AdvertEntity } from './entities/advert.entity';
-import { UserEntity } from './entities/user.entity';
 import { config } from 'dotenv';
 import { resolve } from 'path';
-import { AdvertRepository } from './repository/advert.repository';
+import { DataSource } from 'typeorm';
 import { AbstractPolymorphicRepository } from '../';
+import { AdminEntity } from './entities/admin.entity';
+import { AdvertEntity } from './entities/advert.entity';
 import { MerchantEntity } from './entities/merchant.entity';
+import { UserEntity } from './entities/user.entity';
+import { AdvertRepository } from './repository/advert.repository';
 import { UserRepository } from './repository/user.repository';
 
 describe('AbstractPolymorphicRepository', () => {
@@ -22,7 +23,7 @@ describe('AbstractPolymorphicRepository', () => {
       port: parseInt(process.env.TYPEORM_PORT as string, 10),
       username: process.env.TYPEORM_USERNAME,
       password: process.env.TYPEORM_PASSWORD,
-      entities: [UserEntity, AdvertEntity, MerchantEntity],
+      entities: [UserEntity, AdvertEntity, MerchantEntity, AdminEntity],
       synchronize: process.env.TYPEORM_SYNCHRONIZE === 'true',
       database: process.env.TYPEORM_DATABASE,
     });
@@ -164,6 +165,31 @@ describe('AbstractPolymorphicRepository', () => {
         expect(result?.entityType).toBe(UserEntity.name);
       });
 
+      it('Can find entity with parent even with different primaryColumn', async () => {
+        const repository: AbstractPolymorphicRepository<AdvertEntity> =
+          AbstractPolymorphicRepository.createRepository(
+            connection,
+            AdvertRepository,
+          );
+        const adminRepository = connection.getRepository(AdminEntity);
+
+        const admin = await adminRepository.save(new AdminEntity());
+
+        const advert = await repository.save(
+          repository.create({
+            owner: admin,
+          }),
+        );
+
+        const result = await repository.findOne({ where: { id: advert.id } });
+
+        expect(result).toBeInstanceOf(AdvertEntity);
+        expect(result?.owner).toBeInstanceOf(AdminEntity);
+        const owner = result?.owner as AdminEntity;
+        expect(owner.admin_id).toBe(result?.entityId);
+        expect(result?.entityType).toBe(AdminEntity.name);
+      });
+
       it('Can find entity without parent', async () => {
         const repository = AbstractPolymorphicRepository.createRepository(
           connection,

src/polymorphic.repository.ts

@@ -181,13 +181,25 @@ export abstract class AbstractPolymorphicRepository<
     options: PolymorphicMetadataInterface,
   ): Promise<PolymorphicChildInterface[] | PolymorphicChildInterface | never> {
     const repository = this.findRepository(entityType);
+    // If we are in the child repository, `options` has the child metadata
+    // but not the parent's while options.type == 'parent'. But to 
+    // perform the query below we need the ID of the parent entity. Meaning
+    // we need to read the `primaryColum` option from the parent repository.
+
+    // Act as if the parent repository is the current repository
+    // and extract the metadata from it
+    // FIXME: Come up with a nicer interface to do this
+    const metadata: PolymorphicMetadataInterface[] = this.getPolymorphicMetadata.bind(repository)();
+
+    // Find the metadata associated to the current repository through `target`
+    const found = metadata.find((m) => m.classType === this.target);
 
     return repository[options.hasMany ? 'find' : 'findOne'](
       options.type === 'parent'
         ? {
             where: {
               // TODO: Not sure about this change (key was just id before)
-              [PrimaryColumn(options)]: parent[entityIdColumn(options)],
+              [PrimaryColumn({ primaryColumn: found.primaryColumn, ...options })]: parent[entityIdColumn(options)],
             },
           }
         : {
@@ -266,14 +278,15 @@ export abstract class AbstractPolymorphicRepository<
             return entity;
           }
 
-          /**
-           * Add parent's id and type to child's id and type field
-           */
+          // FIXME: Come up with a nicer interface to do this
+          const repository = this.findRepository(parent.constructor as Function);
+          const parentMetadata: PolymorphicMetadataInterface[] = this.getPolymorphicMetadata.bind(repository)();
+          const found = parentMetadata.find((m) => m.classType === this.target);
           type EntityKey = keyof DeepPartial<E>;
           entity[entityIdColumn(options) as EntityKey] =
-            parent[PrimaryColumn(options)];
+              parent[PrimaryColumn({ primaryColumn: found.primaryColumn, ...options })];
           entity[entityTypeColumn(options) as EntityKey] =
-            parent.constructor.name;
+              parent.constructor.name;
           return entity;
         });
       }