chore: make module loaders DML aware and auto generate joiner config (#7781)

* chore: make module loaders DML aware and auto generate joiner config

* fixes and cleanup

* improve dml entity check

* add unit tests on load resources

* cleanup deps

* cleanup deps

* cleanup Modules

* finalise

* fix modules-sdk jest

* fix modules-sdk jest

* fix import

* fix import

packages/core/utils/src/dml/__tests__/entity-builder.spec.ts

@@ -3,6 +3,7 @@ import { MetadataStorage } from "@mikro-orm/core"
 import { EntityConstructor } from "../types"
 import { EntityBuilder } from "../entity-builder"
 import { createMikrORMEntity } from "../helpers/create-mikro-orm-entity"
+import { DmlEntity } from "../entity"
 
 describe("Entity builder", () => {
   beforeEach(() => {
@@ -10,6 +11,21 @@ describe("Entity builder", () => {
   })
 
   describe("Entity builder | properties", () => {
+    test("should identify a DML entity correctly", () => {
+      const model = new EntityBuilder()
+      const user = model.define("user", {
+        id: model.number(),
+        username: model.text(),
+        email: model.text(),
+      })
+
+      expect(DmlEntity.isDmlEntity(user)).toBe(true)
+
+      const nonDmlEntity = new Object()
+
+      expect(DmlEntity.isDmlEntity(nonDmlEntity)).toBe(false)
+    })
+
     test("define an entity", () => {
       const model = new EntityBuilder()
       const user = model.define("user", {

packages/core/utils/src/dml/entity-builder.ts

@@ -10,9 +10,9 @@ import { BelongsTo } from "./relations/belongs-to"
 import { DateTimeProperty } from "./properties/date-time"
 import { ManyToMany } from "./relations/many-to-many"
 import type {
+  PropertyType,
   RelationshipOptions,
   RelationshipType,
-  PropertyType,
 } from "./types"
 import { NullableModifier } from "./properties/nullable"
 import { IdProperty } from "./properties/id"
@@ -179,3 +179,5 @@ export class EntityBuilder {
     return new ManyToMany<T>(entityBuilder, options || {})
   }
 }
+
+export const model = new EntityBuilder()

packages/core/utils/src/dml/entity.ts

@@ -1,11 +1,13 @@
 import { BelongsTo } from "./relations/belongs-to"
 import {
-  PropertyType,
   EntityCascades,
-  RelationshipType,
   ExtractEntityRelations,
+  PropertyType,
+  RelationshipType,
 } from "./types"
 
+const IsDmlEntity = Symbol("isDmlEntity")
+
 /**
  * Dml entity is a representation of a DML model with a unique
  * name, its schema and relationships.
@@ -13,9 +15,26 @@ import {
 export class DmlEntity<
   Schema extends Record<string, PropertyType<any> | RelationshipType<any>>
 > {
+  [IsDmlEntity] = true
+
   #cascades: EntityCascades<string[]> = {}
   constructor(public name: string, public schema: Schema) {}
 
+  /**
+   * A static method to check if an entity is an instance of DmlEntity.
+   * It allows us to identify a specific object as being an instance of
+   * DmlEntity.
+   *
+   * @param entity
+   */
+  static isDmlEntity(entity: unknown): entity is DmlEntity<any> {
+    return (
+      !!entity &&
+      (entity instanceof DmlEntity ||
+        (typeof entity === "object" && entity[IsDmlEntity] === true))
+    )
+  }
+
   /**
    * Parse entity to get its underlying information
    */

packages/core/utils/src/dml/helpers/create-mikro-orm-entity.ts

@@ -618,3 +618,5 @@ export function createMikrORMEntity() {
     ) as Infer<T>
   }
 }
+
+export const toMikroORMEntity = createMikrORMEntity()

packages/core/utils/src/dml/index.ts

@@ -1,2 +1,3 @@
 export * from "./entity-builder"
+export * from "./entity"
 export * from "./helpers/create-mikro-orm-entity"

packages/core/utils/src/modules-sdk/medusa-service.ts

@@ -22,6 +22,7 @@ import {
 } from "../common"
 import { InjectManager, MedusaContext } from "./decorators"
 import { ModuleRegistrationName } from "./definition"
+import { DmlEntity } from "../dml"
 
 type BaseMethods =
   | "retrieve"
@@ -83,16 +84,20 @@ type ExtractSingularName<T extends Record<any, any>, K = keyof T> = Capitalize<
  * @deprecated should all notion of singular and plural be removed once all modules are aligned with the convention
  * The pluralize will move to where it should be used instead
  */
-type ExtractPluralName<T extends Record<any, any>, K = keyof T> = T[K] extends {
-  plural?: string
-}
-  ? T[K]["plural"] & string
-  : Pluralize<K & string>
+type ExtractPluralName<T extends Record<any, any>, K = keyof T> = Capitalize<
+  T[K] extends {
+    plural?: string
+  }
+    ? T[K]["plural"] & string
+    : Pluralize<K & string>
+>
 
 // TODO: The future expected entry will be a DML object but in the meantime we have to maintain  backward compatibility for ouw own modules and therefore we need to support Constructor<any> as well as this temporary object
 type TEntityEntries<Keys = string> = Record<
   Keys & string,
-  Constructor<any> | { name?: string; singular?: string; plural?: string }
+  | Constructor<any>
+  | DmlEntity<any>
+  | { name?: string; singular?: string; plural?: string }
 >
 
 type ExtractKeysFromConfig<EntitiesConfig> = EntitiesConfig extends {