From 52a756550d8a071e8919b56fe5bcfe7cfbce29ba Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Wed, 5 Jun 2024 09:50:32 -0400
Subject: [PATCH] fix: populate `this.#sources` when constructing reactive map

---
 .changeset/cold-beans-tease.md        | 2 +-
 packages/svelte/src/reactivity/map.js | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.changeset/cold-beans-tease.md b/.changeset/cold-beans-tease.md
index dc02ea7501..7359c27cc0 100644
--- a/.changeset/cold-beans-tease.md
+++ b/.changeset/cold-beans-tease.md
@@ -2,4 +2,4 @@
 'svelte': patch
 ---
 
-fix: increment version when creating new source in Map.get or Map.has
+fix: populate `this.#sources` when constructing reactive map
diff --git a/packages/svelte/src/reactivity/map.js b/packages/svelte/src/reactivity/map.js
index e473bd5292..edf4a3c1f6 100644
--- a/packages/svelte/src/reactivity/map.js
+++ b/packages/svelte/src/reactivity/map.js
@@ -24,7 +24,9 @@ export class ReactiveMap extends Map {
 		if (DEV) new Map(value);
 
 		if (value) {
+			var sources = this.#sources;
 			for (var [key, v] of value) {
+				sources.set(key, source(Symbol()));
 				super.set(key, v);
 			}
 			this.#size.v = super.size;
@@ -45,7 +47,6 @@ export class ReactiveMap extends Map {
 			if (ret !== undefined) {
 				s = source(Symbol());
 				sources.set(key, s);
-				this.#increment_version();
 			} else {
 				// We should always track the version in case
 				// the Set ever gets this value in the future.
@@ -78,7 +79,6 @@ export class ReactiveMap extends Map {
 			if (ret !== undefined) {
 				s = source(Symbol());
 				sources.set(key, s);
-				this.#increment_version();
 			} else {
 				// We should always track the version in case
 				// the Set ever gets this value in the future.