From b2ad07ee999899339e782a88e2a5859a23536c60 Mon Sep 17 00:00:00 2001
From: Gert Hengeveld <info@ghengeveld.nl>
Date: Mon, 16 Dec 2024 22:23:18 +0100
Subject: [PATCH 1/2] Prevent addon state from absolutely bombing render
 performance

---
 code/core/src/manager-api/root.tsx | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/code/core/src/manager-api/root.tsx b/code/core/src/manager-api/root.tsx
index c2784329ab8f..8d5c501607d6 100644
--- a/code/core/src/manager-api/root.tsx
+++ b/code/core/src/manager-api/root.tsx
@@ -41,7 +41,7 @@ import {
   STORY_CHANGED,
 } from '@storybook/core/core-events';
 
-import { mergeWith } from 'es-toolkit';
+import { isEqual } from 'es-toolkit';
 
 import { createContext } from './context';
 import getInitialState from './initial-state';
@@ -218,14 +218,17 @@ class ManagerProvider extends Component<ManagerProviderProps, State> {
     return null!;
   }
 
-  shouldComponentUpdate(nextProps: ManagerProviderProps, nextState: State): boolean {
-    const prevState = this.state;
+  shouldComponentUpdate(
+    nextProps: ManagerProviderProps,
+    { addons: _, ...nextState }: State
+  ): boolean {
     const prevProps = this.props;
+    const { addons: __, ...prevState } = this.state;
 
-    if (prevState !== nextState) {
+    if (prevProps.path !== nextProps.path) {
       return true;
     }
-    if (prevProps.path !== nextProps.path) {
+    if (!isEqual(prevState, nextState)) {
       return true;
     }
     return false;

From 8e2e08f9efa111a419f5e51956073341dfe991e5 Mon Sep 17 00:00:00 2001
From: Gert Hengeveld <info@ghengeveld.nl>
Date: Wed, 18 Dec 2024 14:49:27 +0100
Subject: [PATCH 2/2] Don't ignore addon state as it may be relevant

---
 code/core/src/manager-api/root.tsx | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/code/core/src/manager-api/root.tsx b/code/core/src/manager-api/root.tsx
index 8d5c501607d6..0889a560c8a0 100644
--- a/code/core/src/manager-api/root.tsx
+++ b/code/core/src/manager-api/root.tsx
@@ -218,20 +218,10 @@ class ManagerProvider extends Component<ManagerProviderProps, State> {
     return null!;
   }
 
-  shouldComponentUpdate(
-    nextProps: ManagerProviderProps,
-    { addons: _, ...nextState }: State
-  ): boolean {
+  shouldComponentUpdate(nextProps: ManagerProviderProps, nextState: State): boolean {
     const prevProps = this.props;
-    const { addons: __, ...prevState } = this.state;
-
-    if (prevProps.path !== nextProps.path) {
-      return true;
-    }
-    if (!isEqual(prevState, nextState)) {
-      return true;
-    }
-    return false;
+    const prevState = this.state;
+    return prevProps.path !== nextProps.path || !isEqual(prevState, nextState);
   }
 
   initModules = () => {