From ea3cd515beb52b50cc102629aa95dc9c0f4d1fe0 Mon Sep 17 00:00:00 2001
From: Simon Holthausen <simon.holthausen@vercel.com>
Date: Thu, 12 Mar 2026 12:12:33 +0100
Subject: [PATCH] remove obsolete code

---
 .../src/internal/client/reactivity/batch.js   | 127 ++----------------
 1 file changed, 9 insertions(+), 118 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
index e75501fe83..85025dfe99 100644
--- a/packages/svelte/src/internal/client/reactivity/batch.js
+++ b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -21,7 +21,7 @@ import {
 	USER_EFFECT
 } from '#client/constants';
 import { async_mode_flag } from '../../flags/index.js';
-import { deferred, define_property, includes } from '../../shared/utils.js';
+import { deferred, define_property } from '../../shared/utils.js';
 import {
 	active_effect,
 	active_reaction,
@@ -364,7 +364,6 @@ export class Batch {
 				} else if (async_mode_flag && (flags & (RENDER_EFFECT | MANAGED_EFFECT)) !== 0) {
 					render_effects.push(effect);
 				} else if (is_dirty(effect)) {
-					if ((flags & BLOCK_EFFECT) !== 0) this.#maybe_dirty_effects.add(effect);
 					update_effect(effect);
 				}
 
@@ -501,64 +500,6 @@ export class Batch {
 	}
 
 	#commit() {
-		// If there are other pending batches, they now need to be 'rebased' —
-		// in other words, we re-run block/async effects with the newly
-		// committed state, unless the batch in question has a more
-		// recent value for a given source
-		for (const batch of batches) {
-			var is_earlier = batch.id < this.id;
-
-			/** @type {Source[]} */
-			var sources = [];
-
-			for (const [source, value] of this.current) {
-				if (batch.current.has(source)) {
-					if (is_earlier && value !== batch.current.get(source)) {
-						// bring the value up to date
-						batch.current.set(source, value);
-					} else {
-						// same value or later batch has more recent value,
-						// no need to re-run these effects
-						continue;
-					}
-				}
-
-				sources.push(source);
-			}
-
-			if (sources.length === 0) {
-				continue;
-			}
-
-			// Re-run async/block effects that depend on distinct values changed in both batches
-			var others = [...batch.current.keys()].filter((s) => !this.current.has(s));
-			if (others.length > 0) {
-				batch.activate();
-
-				/** @type {Set<Value>} */
-				var marked = new Set();
-
-				/** @type {Map<Reaction, boolean>} */
-				var checked = new Map();
-
-				for (var source of sources) {
-					mark_effects(source, others, marked, checked);
-				}
-
-				if (batch.#roots.length > 0) {
-					batch.apply();
-
-					for (var root of batch.#roots) {
-						batch.#traverse(root, [], []);
-					}
-
-					// TODO do we need to do anything with the dummy effect arrays?
-				}
-
-				batch.deactivate();
-			}
-		}
-
 		for (const { on_discard } of this.#skipped_branches.values()) {
 			on_discard(this);
 		}
@@ -1031,37 +972,6 @@ function flush_queued_effects(effects) {
 	eager_block_effects = null;
 }
 
-/**
- * This is similar to `mark_reactions`, but it only marks async/block effects
- * depending on `value` and at least one of the other `sources`, so that
- * these effects can re-run after another batch has been committed
- * @param {Value} value
- * @param {Source[]} sources
- * @param {Set<Value>} marked
- * @param {Map<Reaction, boolean>} checked
- */
-function mark_effects(value, sources, marked, checked) {
-	if (marked.has(value)) return;
-	marked.add(value);
-
-	if (value.reactions !== null) {
-		for (const reaction of value.reactions) {
-			const flags = reaction.f;
-
-			if ((flags & DERIVED) !== 0) {
-				mark_effects(/** @type {Derived} */ (reaction), sources, marked, checked);
-			} else if (
-				(flags & (ASYNC | BLOCK_EFFECT)) !== 0 &&
-				(flags & DIRTY) === 0 &&
-				depends_on(reaction, sources, checked)
-			) {
-				set_signal_status(reaction, DIRTY);
-				schedule_effect(/** @type {Effect} */ (reaction));
-			}
-		}
-	}
-}
-
 /**
  * When committing a fork, we need to trigger eager effects so that
  * any `$state.eager(...)` expressions update immediately. This
@@ -1084,33 +994,6 @@ function mark_eager_effects(value, effects) {
 	}
 }
 
-/**
- * @param {Reaction} reaction
- * @param {Source[]} sources
- * @param {Map<Reaction, boolean>} checked
- */
-function depends_on(reaction, sources, checked) {
-	const depends = checked.get(reaction);
-	if (depends !== undefined) return depends;
-
-	if (reaction.deps !== null) {
-		for (const dep of reaction.deps) {
-			if (includes.call(sources, dep)) {
-				return true;
-			}
-
-			if ((dep.f & DERIVED) !== 0 && depends_on(/** @type {Derived} */ (dep), sources, checked)) {
-				checked.set(/** @type {Derived} */ (dep), true);
-				return true;
-			}
-		}
-	}
-
-	checked.set(reaction, false);
-
-	return false;
-}
-
 /**
  * @param {Effect} effect
  * @returns {void}
@@ -1283,6 +1166,14 @@ export function fork(fn) {
 
 			batch.is_fork = false;
 
+			// TODO seems like we don't need this, but maybe worth keeping?
+			// var existing_batch = [...batches].find(
+			// 	(b) => !b.is_fork && batch.current.keys().some((s) => b.current.has(s))
+			// );
+			// if (existing_batch) {
+			// 	Batch.merge(batch, existing_batch);
+			// }
+
 			// apply changes and update write versions so deriveds see the change
 			for (var [source, value] of batch.current) {
 				source.v = value;