fix: skip trailing slash redirection for more internal paths (#14169)

ascorbic · web-flow · commit f4e8889c10c2 · 2025-07-31T14:53:27.000+01:00
* fix: skip trailing slash redirection for more internal paths

* Changes from review
diff --git a/.changeset/common-ducks-trade.md b/.changeset/common-ducks-trade.md
@@ -0,0 +1,5 @@
+---
+'@astrojs/internal-helpers': minor
+---
+
+Adds `isInternalPath` helper
diff --git a/.changeset/flat-shirts-shake.md b/.changeset/flat-shirts-shake.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Skips trailing slash handling for paths that start with `/.`.
diff --git a/.changeset/thirty-ears-guess.md b/.changeset/thirty-ears-guess.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes a bug that prevented images from being displayed in dev when using the Netlify adapter with `trailingSlash` set to `always`
diff --git a/packages/astro/src/core/app/index.ts b/packages/astro/src/core/app/index.ts
@@ -1,4 +1,4 @@
-import { collapseDuplicateTrailingSlashes, hasFileExtension } from '@astrojs/internal-helpers/path';
+import { collapseDuplicateTrailingSlashes, hasFileExtension, isInternalPath } from '@astrojs/internal-helpers/path';
 import { normalizeTheLocale } from '../../i18n/index.js';
 import type { RoutesList } from '../../types/astro.js';
 import type { RouteData, SSRManifest } from '../../types/public/internal.js';
@@ -292,7 +292,7 @@ export class App {
 		const { trailingSlash } = this.#manifest;
 
 		// Ignore root and internal paths
-		if (pathname === '/' || pathname.startsWith('/_')) {
+		if (pathname === '/' || isInternalPath(pathname)) {
 			return pathname;
 		}
 
diff --git a/packages/astro/src/vite-plugin-astro-server/trailing-slash.ts b/packages/astro/src/vite-plugin-astro-server/trailing-slash.ts
@@ -1,4 +1,4 @@
-import { collapseDuplicateTrailingSlashes, hasFileExtension } from '@astrojs/internal-helpers/path';
+import { collapseDuplicateTrailingSlashes, hasFileExtension, isInternalPath } from '@astrojs/internal-helpers/path';
 import type * as vite from 'vite';
 import { trailingSlashMismatchTemplate } from '../template/4xx.js';
 import type { AstroSettings } from '../types/astro.js';
@@ -16,7 +16,7 @@ export function trailingSlashMiddleware(settings: AstroSettings): vite.Connect.N
 			/* malformed uri */
 			return next(e);
 		}
-		if (pathname.startsWith('/_') || pathname.startsWith('/@')) {
+		if (isInternalPath(pathname)) {
 			return next();
 		}
 
diff --git a/packages/astro/test/ssr-trailing-slash.test.js b/packages/astro/test/ssr-trailing-slash.test.js
@@ -115,6 +115,7 @@ describe('Redirecting trailing slashes in SSR', () => {
 				'/_image?url=http://example.com/foo.jpg',
 				'/_server-islands/foo',
 				'/_actions/foo',
+				'/.netlify/image?url=http://example.com/foo.jpg',
 			]) {
 				const request = new Request(`http://example.com${path}`);
 				const response = await app.render(request);
@@ -211,6 +212,7 @@ describe('Redirecting trailing slashes in SSR', () => {
 				'/_image/?url=http://example.com/foo.jpg',
 				'/_server-islands/foo/',
 				'/_actions/foo/',
+				'/.netlify/image/?url=http://example.com/foo.jpg',
 			]) {
 				const request = new Request(`http://example.com${path}/`);
 				const response = await app.render(request);
@@ -259,5 +261,21 @@ describe('Redirecting trailing slashes in SSR', () => {
 			const response = await app.render(request);
 			assert.equal(response.status, 200);
 		});
+
+		it('Does not redirect internal paths', async () => {
+			const app = await fixture.loadTestAdapterApp();
+
+			for (const path of [
+				'/_astro/something//',
+				'/_image//?url=http://example.com/foo.jpg',
+				'/_server-islands/foo//',
+				'/_actions/foo//',
+				'/.netlify/image//?url=http://example.com/foo.jpg',
+			]) {
+				const request = new Request(`http://example.com${path}/`);
+				const response = await app.render(request);
+				assert.notEqual(response.status, 301);
+			}
+		});
 	});
 });
diff --git a/packages/internal-helpers/src/path.ts b/packages/internal-helpers/src/path.ts
@@ -69,6 +69,13 @@ function isString(path: unknown): path is string {
 	return typeof path === 'string' || path instanceof String;
 }
 
+const INTERNAL_PREFIXES = new Set(['/_', '/@', '/.']);
+const JUST_SLASHES = /^\/{2,}$/;
+
+export function isInternalPath(path: string) {
+	return INTERNAL_PREFIXES.has(path.slice(0, 2)) && !JUST_SLASHES.test(path);
+}
+
 export function joinPaths(...paths: (string | undefined)[]) {
 	return paths
 		.filter(isString)

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +'@astrojs/internal-helpers': minor
 +---
++
 +Adds `isInternalPath` helper
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-import { collapseDuplicateTrailingSlashes, hasFileExtension } from '@astrojs/internal-helpers/path';`
	`1`	`+import { collapseDuplicateTrailingSlashes, hasFileExtension, isInternalPath } from '@astrojs/internal-helpers/path';`
`2`	`2`	`import type * as vite from 'vite';`
`3`	`3`	`import { trailingSlashMismatchTemplate } from '../template/4xx.js';`
`4`	`4`	`import type { AstroSettings } from '../types/astro.js';`
`@@ -16,7 +16,7 @@ export function trailingSlashMiddleware(settings: AstroSettings): vite.Connect.N`
`16`	`16`	`/* malformed uri */`
`17`	`17`	`return next(e);`
`18`	`18`	`}`
`19`		`- if (pathname.startsWith('/_') \|\| pathname.startsWith('/@')) {`
	`19`	`+ if (isInternalPath(pathname)) {`
`20`	`20`	`return next();`
`21`	`21`	`}`
`22`	`22`