feat(core): allow calling Collection.set() on not initialized colle…

…ctions

Normally we are diffing the collection snapshot with the current state, issueing
only the right insert/delete queries to sync the state. Now when the collection
is not initialied and we call set, we will remove all the items before adding the
new set of items.

Related #1048

packages/core/src/entity/Collection.ts

@@ -99,6 +99,12 @@ export class Collection<T, O = unknown> extends ArrayCollection<T, O> {
     const unwrapped = items.map(i => Reference.unwrapReference(i));
     unwrapped.forEach(item => this.validateItemType(item));
     this.validateModification(unwrapped);
+
+    if (!this.initialized) {
+      this.initialized = true;
+      this.snapshot = undefined;
+    }
+
     super.set(unwrapped);
     this.setDirty();
     this.cancelOrphanRemoval(unwrapped);
@@ -107,15 +113,10 @@ export class Collection<T, O = unknown> extends ArrayCollection<T, O> {
   /**
    * @internal
    */
-  hydrate(items?: T[]): void {
+  hydrate(items: T[]): void {
     this.initialized = true;
-
-    if (items) {
-      super.hydrate(items);
-      this.takeSnapshot();
-    } else {
-      this.snapshot = undefined;
-    }
+    super.hydrate(items);
+    this.takeSnapshot();
   }
 
   remove(...items: (T | Reference<T>)[]): void {

packages/core/src/entity/EntityAssigner.ts

@@ -120,10 +120,6 @@ export class EntityAssigner {
       throw new Error(`Invalid collection values provided for '${name}.${prop.name}' in ${name}.assign(): ${inspect(invalid)}`);
     }
 
-    if (!collection.isInitialized()) {
-      collection.hydrate();
-    }
-
     collection.set(items);
   }