fix(core): computation of outDir for SSR builds

.changeset/ten-pugs-begin.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes an issue where Astro creates an incorrect folder when `outDir` is defined, and an adapter is used.

packages/astro/src/core/config/schema.ts

@@ -664,13 +664,13 @@ export function createRelativeSchema(cmd: string, fileProtocolRoot: string) {
 				!config.build.server.toString().startsWith(config.outDir.toString()) &&
 				config.build.server.toString().endsWith('dist/server/')
 			) {
-				config.build.server = new URL('./dist/server/', config.outDir);
+				config.build.server = new URL('./server/', config.outDir);
 			}
 			if (
 				!config.build.client.toString().startsWith(config.outDir.toString()) &&
 				config.build.client.toString().endsWith('dist/client/')
 			) {
-				config.build.client = new URL('./dist/client/', config.outDir);
+				config.build.client = new URL('./client/', config.outDir);
 			}
 
 			// Handle `base` trailing slash based on `trailingSlash` config

packages/astro/test/fixtures/ssr-locals/.gitignore

@@ -0,0 +1 @@
+custom-dir

packages/astro/test/ssr-out-dir.test.js

@@ -0,0 +1,31 @@
+import assert from 'node:assert/strict';
+import { before, describe, it } from 'node:test';
+import testAdapter from './test-adapter.js';
+import { loadFixture } from './test-utils.js';
+
+describe('The build', () => {
+	/** @type {import('./test-utils').Fixture} */
+	let fixture;
+	/** @type {import('./test-utils.js').App} */
+	let app;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: './fixtures/ssr-locals/',
+			output: 'server',
+			adapter: testAdapter(),
+			outDir: 'custom-dir',
+		});
+		await fixture.build();
+		app = await fixture.loadTestAdapterApp();
+	});
+
+	it('should output the files in `custom-dir`', async () => {
+		try {
+			await fixture.readFile('/server/entry.mjs');
+			assert.ok(true);
+		} catch (e) {
+			assert.fail(e);
+		}
+	});
+});