From 0ef14b51283ce5dbcef3403f1e729c6b6102f625 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Thu, 19 Sep 2024 04:36:15 -0400
Subject: [PATCH] chore: more `process_effect` tweaks (#13315)

* consolidate more stuff

* simpler

* simplify

* comment is unnecessary, this is the first time we read current_effect.first
---
 .../svelte/src/internal/client/constants.js   |  3 +-
 .../svelte/src/internal/client/runtime.js     | 33 +++++++------------
 2 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/packages/svelte/src/internal/client/constants.js b/packages/svelte/src/internal/client/constants.js
index e5d39046891c..53df86126ac4 100644
--- a/packages/svelte/src/internal/client/constants.js
+++ b/packages/svelte/src/internal/client/constants.js
@@ -18,8 +18,7 @@ export const EFFECT_TRANSPARENT = 1 << 15;
 export const LEGACY_DERIVED_PROP = 1 << 16;
 export const INSPECT_EFFECT = 1 << 17;
 export const HEAD_EFFECT = 1 << 18;
-export const EFFECT_QUEUED = 1 << 19;
-export const EFFECT_HAS_DERIVED = 1 << 20;
+export const EFFECT_HAS_DERIVED = 1 << 19;
 
 export const STATE_SYMBOL = Symbol('$state');
 export const STATE_SYMBOL_METADATA = Symbol('$state metadata');
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 2db62f8eeedb..93f8164ba3de 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -22,8 +22,7 @@ import {
 	BLOCK_EFFECT,
 	ROOT_EFFECT,
 	LEGACY_DERIVED_PROP,
-	DISCONNECTED,
-	EFFECT_QUEUED
+	DISCONNECTED
 } from './constants.js';
 import { flush_tasks } from './dom/task.js';
 import { add_owner } from './dev/ownership.js';
@@ -512,8 +511,8 @@ function flush_queued_root_effects(root_effects) {
 		for (var i = 0; i < length; i++) {
 			var effect = root_effects[i];
 
-			if ((effect.f & EFFECT_QUEUED) !== 0) {
-				effect.f ^= EFFECT_QUEUED;
+			if ((effect.f & CLEAN) === 0) {
+				effect.f ^= CLEAN;
 			}
 
 			/** @type {Effect[]} */
@@ -593,15 +592,10 @@ export function schedule_effect(signal) {
 		effect = effect.parent;
 		var flags = effect.f;
 
-		if ((flags & BRANCH_EFFECT) !== 0) {
+		if ((flags & (ROOT_EFFECT | BRANCH_EFFECT)) !== 0) {
 			if ((flags & CLEAN) === 0) return;
 			effect.f ^= CLEAN;
 		}
-
-		if ((flags & ROOT_EFFECT) !== 0) {
-			if ((flags & EFFECT_QUEUED) !== 0) return;
-			effect.f ^= EFFECT_QUEUED;
-		}
 	}
 
 	queued_root_effects.push(effect);
@@ -624,23 +618,18 @@ function process_effects(effect, collected_effects) {
 
 	main_loop: while (current_effect !== null) {
 		var flags = current_effect.f;
-		var is_active = (flags & INERT) === 0;
 		var is_branch = (flags & BRANCH_EFFECT) !== 0;
-		var is_clean = (flags & CLEAN) !== 0;
-		var child = current_effect.first;
-
-		// Skip this branch if it's clean
-		if (is_active && (!is_branch || !is_clean)) {
-			if (is_branch) {
-				set_signal_status(current_effect, CLEAN);
-			}
+		var is_skippable_branch = is_branch && (flags & CLEAN) !== 0;
 
+		if (!is_skippable_branch && (flags & INERT) === 0) {
 			if ((flags & RENDER_EFFECT) !== 0) {
-				if (!is_branch && check_dirtiness(current_effect)) {
+				if (is_branch) {
+					current_effect.f ^= CLEAN;
+				} else if (check_dirtiness(current_effect)) {
 					update_effect(current_effect);
 				}
-				// Child might have been mutated since running the effect or checking dirtiness
-				child = current_effect.first;
+
+				var child = current_effect.first;
 
 				if (child !== null) {
 					current_effect = child;