fix(cookies): Update Undici to 5.20 and fix cookies behaviour (#6323)

* fix(cookies): Update Undici to 5.20 and fix cookies behaviour

* chore: changeset

1 files changed, 5 insertions, 28 deletions

diff --git a/packages/integrations/netlify/src/netlify-functions.ts b/packages/integrations/netlify/src/netlify-functions.ts
index 0f9b58158..eb6ed7600 100644
--- a/packages/integrations/netlify/src/netlify-functions.ts
+++ b/packages/integrations/netlify/src/netlify-functions.ts
@@ -102,34 +102,11 @@ export const createExports = (manifest: SSRManifest, args: Args) => {
 			isBase64Encoded: responseIsBase64Encoded,
 		};
 
-		// Special-case set-cookie which has to be set an different way :/
-		// The fetch API does not have a way to get multiples of a single header, but instead concatenates
-		// them. There are non-standard ways to do it, and node-fetch gives us headers.raw()
-		// See https://github.com/whatwg/fetch/issues/973 for discussion
-		if (response.headers.has('set-cookie')) {
-			if ('raw' in response.headers) {
-				// Node fetch allows you to get the raw headers, which includes multiples of the same type.
-				// This is needed because Set-Cookie *must* be called for each cookie, and can't be
-				// concatenated together.
-				type HeadersWithRaw = Headers & {
-					raw: () => Record<string, string[]>;
-				};
-
-				const rawPacked = (response.headers as HeadersWithRaw).raw();
-				if ('set-cookie' in rawPacked) {
-					fnResponse.multiValueHeaders = {
-						'set-cookie': rawPacked['set-cookie'],
-					};
-				}
-			} else {
-				const cookies = response.headers.get('set-cookie');
-
-				if (cookies) {
-					fnResponse.multiValueHeaders = {
-						'set-cookie': Array.isArray(cookies) ? cookies : splitCookiesString(cookies),
-					};
-				}
-			}
+		const cookies = response.headers.get('set-cookie');
+		if (cookies) {
+			fnResponse.multiValueHeaders = {
+				'set-cookie': Array.isArray(cookies) ? cookies : splitCookiesString(cookies),
+			};
 		}
 
 		// Apply cookies set via Astro.cookies.set/delete