diff --git a/.changeset/proud-wombats-mate.md b/.changeset/proud-wombats-mate.md
new file mode 100644
index 000000000000..2b80d3a7821e
--- /dev/null
+++ b/.changeset/proud-wombats-mate.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes an issue where SSR error pages would return duplicated custom headers.
diff --git a/packages/astro/src/core/app/index.ts b/packages/astro/src/core/app/index.ts
index 0e776ae9f2c6..26a6523d8ec9 100644
--- a/packages/astro/src/core/app/index.ts
+++ b/packages/astro/src/core/app/index.ts
@@ -439,6 +439,15 @@ export class App {
// this function could throw an error...
originalResponse.headers.delete('Content-type');
} catch {}
+ // we use a map to remove duplicates
+ const mergedHeaders = new Map([
+ ...Array.from(newResponse.headers),
+ ...Array.from(originalResponse.headers),
+ ]);
+ const newHeaders = new Headers();
+ for (const [name, value] of mergedHeaders) {
+ newHeaders.set(name, value);
+ }
return new Response(newResponse.body, {
status,
statusText: status === 200 ? newResponse.statusText : originalResponse.statusText,
@@ -447,10 +456,7 @@ export class App {
// If users see something weird, it's because they are setting some headers they should not.
//
// Although, we don't want it to replace the content-type, because the error page must return `text/html`
- headers: new Headers([
- ...Array.from(newResponse.headers),
- ...Array.from(originalResponse.headers),
- ]),
+ headers: newHeaders,
});
}
diff --git a/packages/astro/test/fixtures/ssr-error/package.json b/packages/astro/test/fixtures/ssr-error/package.json
new file mode 100644
index 000000000000..ee13c03790c2
--- /dev/null
+++ b/packages/astro/test/fixtures/ssr-error/package.json
@@ -0,0 +1,8 @@
+{
+ "name": "@test/ssr",
+ "version": "0.0.0",
+ "private": true,
+ "dependencies": {
+ "astro": "workspace:*"
+ }
+}
diff --git a/packages/astro/test/fixtures/ssr-error/src/pages/[...slug].astro b/packages/astro/test/fixtures/ssr-error/src/pages/[...slug].astro
new file mode 100644
index 000000000000..1fbb67e0c776
--- /dev/null
+++ b/packages/astro/test/fixtures/ssr-error/src/pages/[...slug].astro
@@ -0,0 +1,8 @@
+---
+return new Response("oops", {
+ status: 500,
+ headers: new Headers({
+ "X-Debug": "1234",
+ }),
+});
+---
diff --git a/packages/astro/test/fixtures/ssr-error/src/pages/index.astro b/packages/astro/test/fixtures/ssr-error/src/pages/index.astro
new file mode 100644
index 000000000000..9509e01e50f3
--- /dev/null
+++ b/packages/astro/test/fixtures/ssr-error/src/pages/index.astro
@@ -0,0 +1,6 @@
+
+Hello world
+
+Hello world
+
+
diff --git a/packages/astro/test/ssr-error-pages.test.js b/packages/astro/test/ssr-error-pages.test.js
index f62c507b53d8..9ebc58770d3e 100644
--- a/packages/astro/test/ssr-error-pages.test.js
+++ b/packages/astro/test/ssr-error-pages.test.js
@@ -4,6 +4,34 @@ import * as cheerio from 'cheerio';
import testAdapter from './test-adapter.js';
import { loadFixture } from './test-utils.js';
+describe('Default 500 page', () => {
+ /** @type {import('./test-utils.js').Fixture} */
+ let fixture;
+ /** @type {import('./test-utils.js').App} */
+ let app;
+
+ before(async () => {
+ fixture = await loadFixture({
+ root: './fixtures/ssr-error/',
+ output: 'server',
+ adapter: testAdapter(),
+ // test suite was authored when inlineStylesheets defaulted to never
+ build: { inlineStylesheets: 'never' },
+ });
+ await fixture.build({});
+ app = await fixture.loadTestAdapterApp();
+ });
+
+ it('should correctly merge headers coming from the original response and the 500 response, when calling a catch-all route', async () => {
+ const request = new Request('http://example.com/any');
+ const response = await app.render(request);
+ assert.equal(response.status, 500);
+ assert.equal(response.headers.get('x-debug'), '1234');
+ const html = await response.text();
+ assert.match(html, /oops/);
+ });
+});
+
describe('404 and 500 pages', () => {
/** @type {import('./test-utils.js').Fixture} */
let fixture;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f87bd6cd9e0d..e2daaaf64341 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -3825,6 +3825,12 @@ importers:
specifier: ^10.25.0
version: 10.25.0
+ packages/astro/test/fixtures/ssr-error:
+ dependencies:
+ astro:
+ specifier: workspace:*
+ version: link:../../..
+
packages/astro/test/fixtures/ssr-error-pages:
dependencies:
astro: