From 9802fd460a77bde1d469a6aa887563d11abd9b51 Mon Sep 17 00:00:00 2001
From: "S. Elliott Johnson" <sejohnson@torchcloudconsulting.com>
Date: Fri, 22 Aug 2025 11:49:27 -0600
Subject: [PATCH] improve

---
 .../3-transform/server/transform-server.js    |  2 +-
 packages/svelte/src/internal/server/index.js  | 27 ++++--------
 .../svelte/src/internal/server/payload.js     | 43 ++++++++++---------
 .../_expected/server/index.svelte.js          |  4 +-
 4 files changed, 34 insertions(+), 42 deletions(-)

diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index 0c39f61e97..d420720dea 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
@@ -199,7 +199,7 @@ export function server_component(analysis, options) {
 					b.stmt(b.call('$$render_inner', b.id('$$inner_payload')))
 				])
 			),
-			b.stmt(b.call('$.assign_payload', b.id('$$payload'), b.id('$$inner_payload')))
+			b.stmt(b.call('$$payload.subsume', b.id('$$inner_payload')))
 		];
 	}
 
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index f027da860e..2729fc0d0b 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -513,8 +513,6 @@ export { push, pop } from './context.js';
 
 export { push_element, pop_element, validate_snippet_args } from './dev.js';
 
-export { assign_payload } from './payload.js';
-
 export { snapshot } from '../shared/clone.js';
 
 export { fallback, to_array } from '../shared/utils.js';
@@ -573,28 +571,21 @@ export function valueless_option(payload, children) {
 
 	// post-children, `payload` has child content, possibly also with some number of hydration comments.
 	// we can compact this last chunk of content to see if it matches the select value...
-	let match = false;
 	payload.compact({
 		start: i,
 		fn: (body) => {
 			if (body.replace(/<!---->/g, '') === payload.select_value) {
-				match = true;
+				// ...and if it does match the select value, we can compact the part of the payload representing the `<option ...>`
+				// to add the `selected` attribute to the end.
+				payload.compact({
+					start: i - 1,
+					end: i,
+					fn: (body) => {
+						return body.slice(0, -1) + ' selected>';
+					}
+				});
 			}
 			return body;
 		}
 	});
-
-	if (!match) {
-		return;
-	}
-
-	// ...and if it does match the select value, we can compact the part of the payload representing the `<option ...>`
-	// to add the `selected` attribute to the end.
-	payload.compact({
-		start: i - 1,
-		end: i,
-		fn: (body) => {
-			return body.slice(0, -1) + ' selected>';
-		}
-	});
 }
diff --git a/packages/svelte/src/internal/server/payload.js b/packages/svelte/src/internal/server/payload.js
index 72a83ee705..1877154cb4 100644
--- a/packages/svelte/src/internal/server/payload.js
+++ b/packages/svelte/src/internal/server/payload.js
@@ -194,6 +194,18 @@ export class HeadPayload extends BasePayload {
 		head_payload.out = [...this.out];
 		return head_payload;
 	}
+
+	/**
+	 * @param {HeadPayload} other
+	 */
+	subsume(other) {
+		// @ts-expect-error
+		this.out = [...other.out];
+		this.promise = other.promise;
+		this.#css = other.#css;
+		this.#title = other.#title;
+		this.#uid = other.#uid;
+	}
 }
 
 /**
@@ -250,29 +262,18 @@ export class Payload extends BasePayload {
 		payload.out = [...this.out];
 		return payload;
 	}
-}
 
-/**
- * Assigns second payload to first -- legacy nonsense
- * @param {Payload} p1
- * @param {Payload} p2
- * @returns {void}
- */
-export function assign_payload(p1, p2) {
-	p1.out = [...p2.out];
-	p1.promise = p2.promise;
-	p1.css.clear();
-	for (const entry of p2.css) {
-		p1.css.add(entry);
-	}
-
-	p1.head.out = [...p2.head.out];
-	p1.head.promise = p2.head.promise;
-	p1.head.css.clear();
-	for (const entry of p2.head.css) {
-		p1.head.css.add(entry);
+	/**
+	 * @param {Payload} other
+	 */
+	subsume(other) {
+		// @ts-expect-error
+		this.out = [...other.out];
+		this.promise = other.promise;
+		this.#css = other.#css;
+		this.#uid = other.#uid;
+		this.#head.subsume(other.#head);
 	}
-	p1.head.title.value = p2.head.title.value;
 }
 
 /**
diff --git a/packages/svelte/tests/snapshot/samples/bind-component-snippet/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/bind-component-snippet/_expected/server/index.svelte.js
index e50eddd635..48f57e337a 100644
--- a/packages/svelte/tests/snapshot/samples/bind-component-snippet/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/bind-component-snippet/_expected/server/index.svelte.js
@@ -31,10 +31,10 @@ export default function Bind_component_snippet($$payload) {
 
 		do {
 			$$settled = true;
-			$$inner_payload = $.copy_payload($$payload);
+			$$inner_payload = $$payload.copy();
 			$$render_inner($$inner_payload);
 		} while (!$$settled);
 
-		$.assign_payload($$payload, $$inner_payload);
+		$$payload.subsume($$inner_payload);
 	});
 }
\ No newline at end of file