Remove misleading warning when using a custom renderer (#12461)

* fix: this message adds no value to developers; it checks against a static list of renderers while Astro allows to dynamically add custom  renderers

* feat: added framework-custom example to demonstrate the use of custom renderers with the log message fixed

* chore: changeset added and package lock updated

* chore: fix lint issue, but keeping arguments commented out for reference (real-world use)

* chore: removed the example and updated the changeset accordingly

* test: added fixture and test to prove the new behaviour

* test: removing this specific test since it's only guarding if we ever revert this PR

* Update test

---------

Co-authored-by: Emanuele Stoppa <my.burning@gmail.com>
Co-authored-by: bluwy <bjornlu.dev@gmail.com>

.changeset/chatty-knives-confess.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Removes the misleading log message telling that a custom renderer is not recognized while it clearly is and works.

packages/astro/src/runtime/server/render/component.ts

@@ -260,15 +260,6 @@ If you're still stuck, please open an issue on GitHub or join us at https://astr
 		}
 	} else {
 		if (metadata.hydrate === 'only') {
-			const rendererName = rendererAliases.has(metadata.hydrateArgs)
-				? rendererAliases.get(metadata.hydrateArgs)
-				: metadata.hydrateArgs;
-			if (!clientOnlyValues.has(rendererName)) {
-				// warning if provide incorrect client:only directive but find the renderer by guess
-				console.warn(
-					`The client:only directive for ${metadata.displayName} is not recognized. The renderer ${renderer.name} will be used. If you intended to use a different renderer, please provide a valid client:only directive.`,
-				);
-			}
 			html = await renderSlotToString(result, slots?.fallback);
 		} else {
 			const componentRenderStartTime = performance.now();

packages/astro/test/custom-renderer.test.js

@@ -0,0 +1,42 @@
+import assert from 'node:assert/strict';
+import { after, before, describe, it } from 'node:test';
+import * as cheerio from 'cheerio';
+import { loadFixture } from './test-utils.js';
+
+describe('Custom Renderer - SSR', () => {
+	let fixture;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: './fixtures/custom-renderer/',
+		});
+	});
+
+	describe('dev', () => {
+		let devServer;
+
+		before(async () => {
+			devServer = await fixture.startDevServer();
+		});
+
+		after(async () => {
+			await devServer.stop();
+		});
+
+		it('renders /', async () => {
+			const html = await fixture.fetch('/').then((res) => res.text());
+			const $ = cheerio.load(html);
+			assert.equal($('h1').text(), 'Client Directives');
+		});
+
+		it('renders SSR custom renderer functional components as expected', async () => {
+			const res = await fixture.fetch('/');
+			assert.equal(res.status, 200);
+
+			const html = await res.text();
+			const $ = cheerio.load(html);
+
+			assert.equal($('p').length, 5);
+		});
+	});
+});

packages/astro/test/fixtures/custom-renderer/astro.config.mjs

@@ -0,0 +1,9 @@
+import { defineConfig } from 'astro/config';
+
+// in a real-world scenario, this would be provided a separate package
+import customRenderer from './src/custom-renderer';
+
+// https://astro.build/config
+export default defineConfig({
+  integrations: [customRenderer()]
+});

packages/astro/test/fixtures/custom-renderer/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@test/custom-renderer",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*"
+  },
+  "scripts": {
+    "dev": "astro dev"
+  }
+}

packages/astro/test/fixtures/custom-renderer/src/components/CustomRendererTest.ts

@@ -0,0 +1,10 @@
+export interface Props {
+    msg: string;
+}
+
+export default function CustomRendererTest({ msg }: Props) {
+    return {
+        tag: "p",
+        text: msg
+    }
+}

packages/astro/test/fixtures/custom-renderer/src/custom-renderer/client.ts

@@ -0,0 +1,25 @@
+export default (parentElement: HTMLElement) =>
+
+	async (
+		Component: any,
+		props: Record<string, any>,
+		//{ default: children, ...slotted }: Record<string, any>,
+		//{ client }: Record<string, string>,
+	) => {
+
+		// in a real-world scenario, this would be a more complex function
+		// actually rendering the components return value (which might be an AST/VDOM)
+
+		const vdom = Component(props);
+
+		const node: Node = document.createElement(vdom.tag);
+		node.textContent = `${vdom.text} (rendered by client.ts)`;
+		parentElement.appendChild(node);
+
+		// cleanup
+		parentElement.addEventListener('astro:unmount', () => {
+			if (node.parentNode) {
+				node.parentNode.removeChild(node);
+			}
+    }, { once: true });
+	};

packages/astro/test/fixtures/custom-renderer/src/custom-renderer/index.ts

@@ -0,0 +1,23 @@
+import type { AstroIntegration, AstroRenderer, ContainerRenderer } from 'astro';
+
+const getRenderer = (): AstroRenderer => ({
+    name: 'custom-renderer',
+    clientEntrypoint: '@custom-renderer/client',
+    serverEntrypoint: '@custom-renderer/server',
+})
+
+export const getContainerRenderer = (): ContainerRenderer => ({
+    name: 'custom-renderer',
+    serverEntrypoint: '@custom-renderer/server',
+})
+
+export default function (): AstroIntegration {
+	return {
+		name: 'custom-renderer',
+		hooks: {
+			'astro:config:setup': ({ addRenderer }) => {
+				addRenderer(getRenderer());
+			},
+		},
+	};
+}

packages/astro/test/fixtures/custom-renderer/src/custom-renderer/server.ts

@@ -0,0 +1,42 @@
+import type { NamedSSRLoadedRendererValue, SSRResult } from 'astro';
+
+type RendererContext = {
+	result: SSRResult;
+};
+
+async function check(
+	this: RendererContext,
+	Component: any,
+	//props: Record<string, any>,
+	//children: any,
+) {
+
+	if (typeof Component !== 'function') return false;
+
+	// in a real-world scenario, this would be a more complex function 
+	// that checks if the component should be rendered
+	return true;
+}
+
+async function renderToStaticMarkup(
+	this: RendererContext,
+	Component: any,
+	props: Record<string, any>,
+	//{ default: children, ...slotted }: Record<string, any>,
+	//metadata: AstroComponentMetadata | undefined,
+) {		
+	// in a real-world scenario, this would be a more complex function
+	// actually rendering the components return value (which might be an AST/VDOM)
+	// and render it as an HTML string
+	const vdom = Component(props);
+	return { attrs: {}, html: `<${vdom.tag}>${vdom.text} (rendered by server.ts)</${vdom.tag}>` };
+}
+
+const renderer: NamedSSRLoadedRendererValue = {
+	name: 'custom-renderer',
+	check,
+	renderToStaticMarkup,
+	supportsAstroStaticSlot: false,
+};
+
+export default renderer;

packages/astro/test/fixtures/custom-renderer/src/pages/index.astro

@@ -0,0 +1,30 @@
+---
+import CustomRendererTest from '../components/CustomRendererTest';
+---
+
+<html>
+	<head>
+		<title>Custom Framework / Custom Renderer</title>
+	</head>
+	<body>
+		<h1>Client Directives</h1>
+		<div>
+			<CustomRendererTest msg="client:only" client:only="custom-renderer" />
+		</div>
+		<div>
+			<CustomRendererTest msg="client:load" client:load />
+		</div>
+		<div>
+			<CustomRendererTest msg="client:visible" client:visible />
+		</div>
+		<div>
+			<CustomRendererTest msg="client:media" client:media="(max-width: 50em)" />
+		</div>
+		<div>
+			<CustomRendererTest msg="client:idle" client:idle />
+		</div>
+		<div>
+			<CustomRendererTest msg="none (SSR)" />
+		</div>
+	</body>
+</html>

packages/astro/test/fixtures/custom-renderer/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "astro/tsconfigs/base",
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@custom-renderer/*": ["src/custom-renderer/*"]
+    },
+  }
+}

pnpm-lock.yaml

@@ -968,6 +968,12 @@ importers:
         specifier: ^18.3.1
         version: 18.3.1(react@18.3.1)
 
+  packages/astro/e2e/fixtures/custom-renderer:
+    dependencies:
+      astro:
+        specifier: workspace:*
+        version: link:../../..
+
   packages/astro/e2e/fixtures/dev-toolbar:
     dependencies:
       '@astrojs/preact':
@@ -2942,6 +2948,12 @@ importers:
         specifier: workspace:*
         version: link:../../..
 
+  packages/astro/test/fixtures/custom-renderer:
+    dependencies:
+      astro:
+        specifier: workspace:*
+        version: link:../../..
+
   packages/astro/test/fixtures/data-collections:
     dependencies:
       astro: