Can't generate migration when extending ProductVariant entity - TypeORMError

[AlexTechNoir]

Good day!

I'm trying to extend ProductVariant entity, following docs. I've created the files:

src/models/productVariant.ts:

import { Column, Entity, BeforeInsert } from "typeorm"
import {
  ProductVariant as MedusaProductVariant,
} from "@medusajs/medusa"
import { generateEntityId } from "@medusajs/medusa/dist/utils"

@Entity()
export class ProductVariant extends MedusaProductVariant {
  @Column({ type: 'json' })
  data_images: VariantImage[]
}

@Entity()
export class VariantImage {
  @Column({ type: "varchar" })
  id: string

  @Column({ type: "varchar" })
  variant_id: string

  @Column({ type: "text" })
  url: string

  @Column({ type: "text" })
  alt_text: string

  @BeforeInsert()
  private beforeInsert(): void {
    this.id = generateEntityId(this.id, "VariantImage")
  }
}

datasource.js:

const { DataSource } = require("typeorm")

require('dotenv').config()

const AppDataSource = new DataSource({
  type: "postgres",
  port: 5433,
  username: process.env.DATABASE_USERNAME,
  password: process.env.DATABASE_PASSWORD,
  database: process.env.DATABASE_NAME,
  synchronize: true,
  entities: [
    "dist/models/*.js",
  ],
  migrations: [
    "dist/migrations/*.js",
  ],
})

module.exports = {
  datasource: AppDataSource,
}

(and just in case, here's my typeORM config)
ormconfig.js:

require('dotenv').config()

module.exports = {
  type: "postgres",
  host: "localhost",
  port: 5433,
  username: process.env.DATABASE_USERNAME,
  password: process.env.DATABASE_PASSWORD,
  database: process.env.DATABASE_NAME,
  synchronize: true,
  logging: false,
  entities: [
    "dist/models/**/*.js"
  ],
  migrations: [
    "dist/migrations/**/*.js"
  ],
  cli: {
    entitiesDir: "src/models",
    migrationsDir: "src/migrations"
  }
}

After npm run build, when I run npx typeorm migration:generate -d datasource.js src/migrations/ProductVariantExtend the terminal shows me TypeORM error:

Error during migration generation:
TypeORMError: Entity metadata for ProductVariant#product was not found. Check if you specified a correct entity object and if it's connected in the connection options.
    at C:\Users\Alex\Desktop\Code\medusa-project\backend\node_modules\typeorm\metadata-builder\EntityMetadataBuilder.js:723:23

In EntityMetadataBuilder.js the error originates from here:

. . .
    /**
     * Computes entity metadata's relations inverse side properties.
     */
    computeInverseProperties(entityMetadata, entityMetadatas) {
        entityMetadata.relations.forEach((relation) => {
            // compute inverse side (related) entity metadatas for all relation metadatas
            const inverseEntityMetadata = entityMetadatas.find((m) => {

              // this log is mine
              console.log(m.target, relation.type, m.targetName, m.givenTableName)
              
              return m.target === relation.type ||
                (typeof relation.type === "string" &&
                    (m.targetName === relation.type ||
                        m.givenTableName === relation.type))});
            if (!inverseEntityMetadata)
                throw new error_1.TypeORMError("Entity metadata for " +
                    entityMetadata.name +
                    "#" +
                    relation.propertyPath +
                    " was not found. Check if you specified a correct entity object and if it's connected in the connection options.");
. . . 

We can see that the error appears because of inverseEntityMetadata being falsey. All conditions inside .find() function are false - I checked. The values I put in my console.log above show the following:

[Function: ProductVariant] [Function: Product] ProductVariant undefined
[Function: VariantImage] [Function: Product] VariantImage undefined

I found two answers in the corresponding issue in TypeORM's github. I don't think I misspelled anything, as I copied code from docs. Judging by the first answer, in my case TypeORM didn't find relation between ProductVariant and Product entities.

What does this relation has to do with extending ProductVariant? And how can I resolve this migration generation issue?

[shavidze]

Did you resolve it?

[AlexTechNoir]

Sorry for the long answer. No, I didn't. I gave up on extending entities and ended up creating separate ones with the array of ids of other entities that I wanted to relate.

[imash96]

use the below code as your datasource. You have to also add core entities in entities array. And later you have to also edit the generated migation file also.

const { DataSource } = require("typeorm")
require('dotenv').config()

const AppDataSource = new DataSource({
  type: "postgres",
  url: process.env.DATABASE_URL,
  database: "railway",
  entities: [
    "./dist/models/*.js",
    "./node_modules/@medusajs/medusa/dist/models/*.js",
  ],
  migrations: [
    "./dist/migrations/*.js",
  ],
})

AppDataSource.initialize().then(async () => {
  console.log('Data Source has been initialized!');
}).catch((err) => {
  console.error('Error during Data Source initialization', err);
});

module.exports = {
  datasource: AppDataSource,
}

[AlexTechNoir]

@imash96, are there any ways to extend entities without editing migration files?

[imash96]

As of now there is no way either edit the generated migration file and remove the unwanted lines or write you own migration file.

I have extended many core entities and then generate the migration file from cli and later removed the unwanted line from the migration file and kept only the lines which I have added in my extended models.