From 1f0ac5b276ee12072855e0a0a1f37682b5a8205a Mon Sep 17 00:00:00 2001
From: zubiden <19638254+zubiden@users.noreply.github.com>
Date: Sun, 22 Feb 2026 23:43:18 +0100
Subject: [PATCH] Teact: Align effect order with other libraries (#6685)

---
 src/components/App.tsx                   |   2 +-
 src/components/test/TestCleanupOrder.tsx | 105 +++++++++++++++--------
 src/lib/teact/teact.ts                   |  49 +++++++++--
 3 files changed, 109 insertions(+), 47 deletions(-)

diff --git a/src/components/App.tsx b/src/components/App.tsx
index 8effa288b..ff8d7dd16 100644
--- a/src/components/App.tsx
+++ b/src/components/App.tsx
@@ -24,7 +24,7 @@ import usePrevious from '../hooks/usePrevious';
 import { useSignalEffect } from '../hooks/useSignalEffect';
 import { getIsInBackground } from '../hooks/window/useBackgroundMode';
 
-// import Test from './test/TestSvg';
+// import Test from './test/TestCleanupOrder';
 import Auth from './auth/Auth';
 import Notifications from './common/Notifications';
 import UiLoader from './common/UiLoader';
diff --git a/src/components/test/TestCleanupOrder.tsx b/src/components/test/TestCleanupOrder.tsx
index 2eeaede7c..139475e55 100644
--- a/src/components/test/TestCleanupOrder.tsx
+++ b/src/components/test/TestCleanupOrder.tsx
@@ -1,53 +1,84 @@
-import { useEffect, useLayoutEffect, useState } from '../../lib/teact/teact';
-
-const TestCleanupOrder = () => {
-  const [, setRand] = useState(Math.random());
+/* eslint-disable no-console */
+import { type TeactNode, useEffect, useLayoutEffect, useState } from '../../lib/teact/teact';
 
+function Component1({ children }: { children?: TeactNode }) {
   useEffect(() => {
-    // eslint-disable-next-line no-console
-    console.log('effect 1');
-
-    setTimeout(() => {
-      setRand(Math.random());
-    }, 3000);
-
-    return () => {
-      // eslint-disable-next-line no-console
-      console.log('cleanup 1');
-    };
+    console.log('Effect 1');
+    return () => console.log('Cleanup 1');
   });
 
   useEffect(() => {
-    // eslint-disable-next-line no-console
-    console.log('effect 2');
-
-    return () => {
-      // eslint-disable-next-line no-console
-      console.log('cleanup 2');
-    };
+    console.log('Effect 1.2');
+    return () => console.log('Cleanup 1.2');
   });
 
   useLayoutEffect(() => {
-    // eslint-disable-next-line no-console
-    console.log('layout effect 1');
-
-    return () => {
-      // eslint-disable-next-line no-console
-      console.log('layout cleanup 1');
-    };
+    console.log('Layout 1');
+    return () => console.log('Layout Cleanup 1');
   });
 
   useLayoutEffect(() => {
-    // eslint-disable-next-line no-console
-    console.log('layout effect 2');
+    console.log('Layout 1.2');
+    return () => console.log('Layout Cleanup 1.2');
+  });
+  return children;
+}
 
-    return () => {
-      // eslint-disable-next-line no-console
-      console.log('layout cleanup 2');
-    };
+function Component1B({ children }: { children?: TeactNode }) {
+  useEffect(() => {
+    console.log('Effect 1b');
+    return () => console.log('Cleanup 1b');
   });
 
-  return <div>Test</div>;
-};
+  useLayoutEffect(() => {
+    console.log('Layout 1b');
+    return () => console.log('Layout Cleanup 1b');
+  });
+  return 'B';
+}
+
+function Component2({ children }: { children?: TeactNode }) {
+  useEffect(() => {
+    console.log('Effect 2');
+    return () => console.log('Cleanup 2');
+  });
+
+  useLayoutEffect(() => {
+    console.log('Layout 2');
+    return () => console.log('Layout Cleanup 2');
+  });
+  return children;
+}
+
+function Component3() {
+  useEffect(() => {
+    console.log('Effect 3');
+    return () => console.log('Cleanup 3');
+  });
+
+  useLayoutEffect(() => {
+    console.log('Layout 3');
+    return () => console.log('Layout Cleanup 3');
+  });
+  return <div>Leaf</div>;
+}
+
+function TestCleanupOrder() {
+  const [isMounted, setIsMounted] = useState(true);
+  return (
+    <div style="padding: 1rem" onClick={() => setIsMounted((p) => !p)}>
+      {isMounted && (
+        <>
+          <Component1>
+            <Component2>
+              <Component3 />
+            </Component2>
+          </Component1>
+          <Component1B />
+        </>
+      )}
+    </div>
+  );
+}
 
 export default TestCleanupOrder;
diff --git a/src/lib/teact/teact.ts b/src/lib/teact/teact.ts
index 8d1f9a663..0a0146366 100644
--- a/src/lib/teact/teact.ts
+++ b/src/lib/teact/teact.ts
@@ -155,6 +155,7 @@ const Fragment = Symbol('Fragment') as unknown as FC<{ children: TeactNode }>;
 const DEBUG_RENDER_THRESHOLD = 7;
 const DEBUG_EFFECT_THRESHOLD = 7;
 const DEBUG_SILENT_RENDERS_FOR = new Set(['TeactMemoWrapper', 'TeactNContainer', 'Button', 'ListItem', 'MenuItem']);
+const MAX_EFFECT_CURSORS_PER_INSTANCE = 10000;
 
 let contextCounter = 0;
 
@@ -315,12 +316,37 @@ if (DEBUG) {
 
 let instancesPendingUpdate = new Set<ComponentInstance>();
 let idsToExcludeFromUpdate = new Set<number>();
-let pendingEffects = new Map<string, Effect>();
-let pendingCleanups = new Map<string, EffectCleanup>();
-let pendingLayoutEffects = new Map<string, Effect>();
-let pendingLayoutCleanups = new Map<string, EffectCleanup>();
+let pendingEffects = new Map<number, Effect>();
+let pendingCleanups = new Map<number, EffectCleanup>();
+let pendingLayoutEffects = new Map<number, Effect>();
+let pendingLayoutCleanups = new Map<number, EffectCleanup>();
 let areImmediateEffectsCaptured = false;
 
+/*
+  Effect call order:
+  - Regular call order inside component
+  - Child to parent
+  - Parent to child on unmount
+  - Sibling behavior is not defined
+*/
+function runEffectsMap<T extends NoneToVoidFunction>(map: Map<number, T>) {
+  Array.from(map.entries())
+    .sort(([aKey], [bKey]) => {
+      const idA = Math.floor(aKey / MAX_EFFECT_CURSORS_PER_INSTANCE);
+      const idB = Math.floor(bKey / MAX_EFFECT_CURSORS_PER_INSTANCE);
+
+      const idDiff = idB - idA;
+      if (idDiff !== 0) {
+        return idDiff;
+      }
+
+      const cursorA = aKey % MAX_EFFECT_CURSORS_PER_INSTANCE;
+      const cursorB = bKey % MAX_EFFECT_CURSORS_PER_INSTANCE;
+
+      return cursorA - cursorB;
+    }).forEach(([_, cb]) => void cb());
+}
+
 /*
   Order:
   - component effect cleanups
@@ -350,11 +376,11 @@ const runUpdatePassOnRaf = throttleWith(requestMeasure, () => {
 
   const currentCleanups = pendingCleanups;
   pendingCleanups = new Map();
-  currentCleanups.forEach((cb) => cb());
+  runEffectsMap(currentCleanups);
 
   const currentEffects = pendingEffects;
   pendingEffects = new Map();
-  currentEffects.forEach((cb) => cb());
+  runEffectsMap(currentEffects);
 
   requestMutation(() => {
     instancesToUpdate.forEach(prepareComponentForFrame);
@@ -382,11 +408,11 @@ export function captureImmediateEffects() {
 function runCapturedImmediateEffects() {
   const currentLayoutCleanups = pendingLayoutCleanups;
   pendingLayoutCleanups = new Map();
-  currentLayoutCleanups.forEach((cb) => cb());
+  runEffectsMap(currentLayoutCleanups);
 
   const currentLayoutEffects = pendingLayoutEffects;
   pendingLayoutEffects = new Map();
-  currentLayoutEffects.forEach((cb) => cb());
+  runEffectsMap(currentLayoutEffects);
 
   areImmediateEffectsCaptured = false;
 }
@@ -738,6 +764,11 @@ function useEffectBase(
   }
 
   renderingInstance.hooks.effects.cursor++;
+
+  if (DEBUG && cursor >= MAX_EFFECT_CURSORS_PER_INSTANCE) {
+    // eslint-disable-next-line no-console
+    console.warn(`[Teact] Effect cursor #${cursor} in ${componentInstance.name} is out of bounds. How?`);
+  }
 }
 
 function scheduleEffect(
@@ -750,7 +781,7 @@ function scheduleEffect(
   const cleanup = byCursor[cursor]?.cleanup;
   const cleanupsContainer = isLayout ? pendingLayoutCleanups : pendingCleanups;
   const effectsContainer = isLayout ? pendingLayoutEffects : pendingEffects;
-  const effectId = `${componentInstance.id}_${cursor}`;
+  const effectId = componentInstance.id * MAX_EFFECT_CURSORS_PER_INSTANCE + cursor;
 
   if (cleanup) {
     const runEffectCleanup = () => safeExec(() => {