fix: bump undici to v5.20.0 (#6355)

* fix: bump `undici` to v5.20.0

* fix(cookies): Hopefully the last time we mess with undici and cookies

* chore: add @astrojs/telemetry to changeset

---------

Co-authored-by: Princesseuh <princssdev@gmail.com>
Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

.changeset/yellow-kings-rhyme.md

@@ -0,0 +1,6 @@
+---
+'@astrojs/webapi': patch
+'@astrojs/telemetry': patch
+---
+
+Update `undici` to v5.20.0

packages/astro/src/core/cookies/response.ts

@@ -15,12 +15,14 @@ function getFromResponse(response: Response): AstroCookies | undefined {
 	}
 }
 
-export function* getSetCookiesFromResponse(response: Response): Generator<string, void, unknown> {
+export function* getSetCookiesFromResponse(response: Response): Generator<string, string[]> {
 	const cookies = getFromResponse(response);
 	if (!cookies) {
-		return;
+		return [];
 	}
 	for (const headerValue of cookies.headers()) {
 		yield headerValue;
 	}
+
+	return [];
 }

packages/astro/src/vite-plugin-astro-server/response.ts

@@ -55,19 +55,24 @@ export function writeHtmlResponse(res: http.ServerResponse, statusCode: number,
 export async function writeWebResponse(res: http.ServerResponse, webResponse: Response) {
 	const { status, headers, body } = webResponse;
 
+	// Attach any set-cookie headers added via Astro.cookies.set()
+	const setCookieHeaders = Array.from(getSetCookiesFromResponse(webResponse));
+	setCookieHeaders.forEach((cookie) => {
+		headers.append('set-cookie', cookie);
+	});
+
 	const _headers = Object.fromEntries(headers.entries());
 
 	// Undici 5.20.0+ includes a `getSetCookie` helper that returns an array of all the `set-cookies` headers.
 	// Previously, `headers.entries()` would already have these merged, but it seems like this isn't the case anymore.
-	if ('getSetCookie' in headers && typeof headers.getSetCookie === 'function') {
-		_headers['set-cookie'] = headers.getSetCookie();
+	if (headers.has('set-cookie')) {
+		if ('getSetCookie' in headers && typeof headers.getSetCookie === 'function') {
+			_headers['set-cookie'] = headers.getSetCookie();
+		} else {
+			_headers['set-cookie'] = headers.get('set-cookie')!;
+		}
 	}
 
-	// Attach any set-cookie headers added via Astro.cookies.set()
-	const setCookieHeaders = Array.from(getSetCookiesFromResponse(webResponse));
-	if (setCookieHeaders.length) {
-		res.setHeader('Set-Cookie', setCookieHeaders);
-	}
 	res.writeHead(status, _headers);
 	if (body) {
 		if (Symbol.for('astro.responseBody') in webResponse) {

packages/webapi/package.json

@@ -50,7 +50,7 @@
   "bugs": "https://github.com/withastro/astro/issues",
   "homepage": "https://github.com/withastro/astro/tree/main/packages/webapi#readme",
   "dependencies": {
-    "undici": "5.18.0"
+    "undici": "5.20.0"
   },
   "devDependencies": {
     "@rollup/plugin-alias": "^3.1.9",