fix: Ensure values in patches are never a draft, fixes #559

__tests__/patch.js

@@ -3,7 +3,8 @@ import produce, {
 	setUseProxies,
 	applyPatches,
 	produceWithPatches,
-	enableAllPlugins
+	enableAllPlugins,
+	isDraft
 } from "../src/immer"
 
 enableAllPlugins()
@@ -1014,3 +1015,36 @@ test("#521", () => {
 		new Map([["hello", new Set(["world", "immer"])]])
 	)
 })
+
+test("#559 patches works in a nested reducer with proxies", () => {
+	setUseProxies(true)
+
+	const state = {
+		x: 1,
+		sub: {
+			y: [{a: 0}, {a: 1}]
+		}
+	}
+
+	const changes = []
+	const inverseChanges = []
+
+	const newState = produce(state, draft => {
+		draft.sub = produce(
+			draft.sub,
+			draft => {
+				draft.y.pop()
+			},
+			(patches, inversePatches) => {
+				expect(isDraft(inversePatches[0].value)).toBeFalsy()
+				expect(inversePatches[0].value).toMatchObject({a: 1})
+				changes.push(...patches)
+				inverseChanges.push(...inversePatches)
+			}
+		)
+	})
+
+	const reversedSubState = applyPatches(newState.sub, inverseChanges)
+
+	expect(reversedSubState).toMatchObject(state.sub)
+})

src/plugins/patches.ts

@@ -26,6 +26,7 @@ import {
 	ArchtypeArray,
 	die
 } from "../internal"
+import {isDraft} from "../utils/common"
 
 export function enablePatches() {
 	const REPLACE = "replace"
@@ -98,12 +99,14 @@ export function enablePatches() {
 				patches.push({
 					op: REPLACE,
 					path,
-					value: copy_[i]
+					// Need to maybe clone it, as it can in fact be the original value
+					// due to the base/copy inversion at the start of this function
+					value: clonePatchValueIfNeeded(copy_[i])
 				})
 				inversePatches.push({
 					op: REPLACE,
 					path,
-					value: base_[i]
+					value: clonePatchValueIfNeeded(base_[i])
 				})
 			}
 		}
@@ -116,7 +119,9 @@ export function enablePatches() {
 			patches[replaceCount + i - end] = {
 				op: ADD,
 				path,
-				value: copy_[i]
+				// Need to maybe clone it, as it can in fact be the original value
+				// due to the base/copy inversion at the start of this function
+				value: clonePatchValueIfNeeded(copy_[i])
 			}
 			inversePatches.push({
 				op: REMOVE,
@@ -144,8 +149,8 @@ export function enablePatches() {
 				op === ADD
 					? {op: REMOVE, path}
 					: op === REMOVE
-					? {op: ADD, path, value: origValue}
-					: {op: REPLACE, path, value: origValue}
+					? {op: ADD, path, value: clonePatchValueIfNeeded(origValue)}
+					: {op: REPLACE, path, value: clonePatchValueIfNeeded(origValue)}
 			)
 		})
 	}
@@ -287,6 +292,12 @@ export function enablePatches() {
 		return cloned
 	}
 
+	function clonePatchValueIfNeeded<T>(obj: T): T {
+		if (isDraft(obj)) {
+			return deepClonePatchValue(obj)
+		} else return obj
+	}
+
 	loadPlugin("Patches", {
 		applyPatches_,
 		generatePatches_,