From 19398292130ed04f5779e8354fef07fa62c8e410 Mon Sep 17 00:00:00 2001
From: Ivan Artemiev <29709626+iartemiev@users.noreply.github.com>
Date: Tue, 24 Aug 2021 12:19:05 -0400
Subject: [PATCH] fix(@aws-amplify/datastore): check read-only at instance
 level (#8794)

---
 packages/datastore/src/datastore/datastore.ts | 94 +++++++++----------
 1 file changed, 43 insertions(+), 51 deletions(-)

diff --git a/packages/datastore/src/datastore/datastore.ts b/packages/datastore/src/datastore/datastore.ts
index 94e21b58205..989433c332f 100644
--- a/packages/datastore/src/datastore/datastore.ts
+++ b/packages/datastore/src/datastore/datastore.ts
@@ -49,7 +49,6 @@ import {
 	ErrorHandler,
 	SyncExpression,
 	AuthModeStrategyType,
-	ModelFields,
 } from '../types';
 import {
 	DATASTORE,
@@ -374,13 +373,18 @@ const createModelClass = <T extends PersistentModel>(
 						_deleted,
 					} = modelInstanceMetadata;
 
-					const id =
-						// instancesIds is set by modelInstanceCreator, it is accessible only internally
-						_id !== null && _id !== undefined
-							? _id
-							: modelDefinition.syncable
-							? uuid4()
-							: ulid();
+					// instancesIds are set by modelInstanceCreator, it is accessible only internally
+					const isInternal = _id !== null && _id !== undefined;
+
+					const id = isInternal
+						? _id
+						: modelDefinition.syncable
+						? uuid4()
+						: ulid();
+
+					if (!isInternal) {
+						checkReadOnlyPropertyOnCreate(draft, modelDefinition);
+					}
 
 					draft.id = id;
 
@@ -419,6 +423,7 @@ const createModelClass = <T extends PersistentModel>(
 
 			if (patches.length) {
 				modelPatchesMap.set(model, [patches, source]);
+				checkReadOnlyPropertyOnUpdate(patches, modelDefinition);
 			}
 
 			return model;
@@ -449,6 +454,36 @@ const createModelClass = <T extends PersistentModel>(
 	return clazz;
 };
 
+const checkReadOnlyPropertyOnCreate = <T extends PersistentModel>(
+	draft: T,
+	modelDefinition: SchemaModel
+) => {
+	const modelKeys = Object.keys(draft);
+	const { fields } = modelDefinition;
+
+	modelKeys.forEach(key => {
+		if (fields[key] && fields[key].isReadOnly) {
+			throw new Error(`${key} is read-only.`);
+		}
+	});
+};
+
+const checkReadOnlyPropertyOnUpdate = (
+	patches: Patch[],
+	modelDefinition: SchemaModel
+) => {
+	const patchArray = patches.map(p => [p.path[0], p.value]);
+	const { fields } = modelDefinition;
+
+	patchArray.forEach(([key, val]) => {
+		if (!val || !fields[key]) return;
+
+		if (fields[key].isReadOnly) {
+			throw new Error(`${key} is read-only.`);
+		}
+	});
+};
+
 const createNonModelClass = <T>(typeDefinition: SchemaNonModel) => {
 	const clazz = <NonModelTypeConstructor<T>>(<unknown>class Model {
 		constructor(init: ModelInit<T>) {
@@ -815,9 +850,6 @@ class DataStore {
 
 		const modelDefinition = getModelDefinition(modelConstructor);
 
-		// ensuring "read-only" data isn't being overwritten
-		this.checkReadOnlyProperty(modelDefinition.fields, model, patchesTuple);
-
 		const producedCondition = ModelPredicateCreator.createFromExisting(
 			modelDefinition,
 			condition
@@ -835,46 +867,6 @@ class DataStore {
 		return savedModel;
 	};
 
-	private checkReadOnlyProperty(
-		fields: ModelFields,
-		model: Record<string, any>,
-		patchesTuple: [
-			Patch[],
-			Readonly<
-				{
-					id: string;
-				} & Record<string, any>
-			>
-		]
-	) {
-		if (!patchesTuple) {
-			// saving a new model instance
-			const modelKeys = Object.keys(model);
-			modelKeys.forEach(key => {
-				if (fields[key] && fields[key].isReadOnly) {
-					throw new Error(`${key} is read-only.`);
-				}
-			});
-		} else {
-			// * Updating an existing instance via 'patchesTuple'
-			// patchesTuple[0] is an object that contains the info we need
-			// like the 'path' (mapped to the model's key) and the 'value' of the patch
-			const patchArray = patchesTuple[0].map(p => [p.path[0], p.value]);
-			patchArray.forEach(patch => {
-				const [key, val] = [...patch];
-
-				// the value of a read-only field should be undefined - if so, no need to do the following check
-				if (!val || !fields[key]) return;
-
-				// if the value is NOT undefined, we have to check the 'isReadOnly' property
-				// and throw an error to avoid persisting a mutation
-				if (fields[key].isReadOnly) {
-					throw new Error(`${key} is read-only.`);
-				}
-			});
-		}
-	}
-
 	setConflictHandler = (config: DataStoreConfig): ConflictHandler => {
 		const { DataStore: configDataStore } = config;