Fix head propagation for MDX components (#7838)

10 files changed, 15 insertions, 52 deletions

diff --git a/.changeset/friendly-bulldogs-flash.md b/.changeset/friendly-bulldogs-flash.md
new file mode 100644
index 000000000..88a4c88d3
--- /dev/null
+++ b/.changeset/friendly-bulldogs-flash.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix head propagation for MDX components
diff --git a/packages/astro/src/@types/astro.ts b/packages/astro/src/@types/astro.ts
index 635ef0331..fb34954ac 100644
--- a/packages/astro/src/@types/astro.ts
+++ b/packages/astro/src/@types/astro.ts
@@ -2033,8 +2033,6 @@ export interface SSRMetadata {
 	headInTree: boolean;
 	extraHead: string[];
 	propagators: Map<AstroComponentFactory, AstroComponentInstance>;
-	// Used to key track of unique content; links and script tags
-	contentKeys: Set<string>;
 }
 
 /* Preview server stuff */
diff --git a/packages/astro/src/content/runtime.ts b/packages/astro/src/content/runtime.ts
index b125eeaac..fe77524cf 100644
--- a/packages/astro/src/content/runtime.ts
+++ b/packages/astro/src/content/runtime.ts
@@ -7,7 +7,7 @@ import {
 	createHeadAndContent,
 	renderComponent,
 	renderTemplate,
-	renderUniqueScriptElement,
+	renderScriptElement,
 	renderUniqueStylesheet,
 	unescapeHTML,
 	type AstroComponentFactory,
@@ -303,9 +303,7 @@ async function render({
 						.join('');
 				}
 				if (Array.isArray(collectedScripts)) {
-					scripts = collectedScripts
-						.map((script: any) => renderUniqueScriptElement(result, script))
-						.join('');
+					scripts = collectedScripts.map((script: any) => renderScriptElement(script)).join('');
 				}
 
 				let props = baseProps;
diff --git a/packages/astro/src/core/render/result.ts b/packages/astro/src/core/render/result.ts
index 2bfdb99b0..968b232d4 100644
--- a/packages/astro/src/core/render/result.ts
+++ b/packages/astro/src/core/render/result.ts
@@ -258,7 +258,6 @@ export function createResult(args: CreateResultArgs): SSRResult {
 			headInTree: false,
 			extraHead: [],
 			propagators: new Map(),
-			contentKeys: new Set(),
 		},
 	};
 
diff --git a/packages/astro/src/runtime/server/index.ts b/packages/astro/src/runtime/server/index.ts
index 0fb85b3ce..aca260d00 100644
--- a/packages/astro/src/runtime/server/index.ts
+++ b/packages/astro/src/runtime/server/index.ts
@@ -27,7 +27,6 @@ export {
 	renderSlotToString,
 	renderTemplate,
 	renderToString,
-	renderUniqueScriptElement,
 	renderUniqueStylesheet,
 	voidElementNames,
 } from './render/index.js';
diff --git a/packages/astro/src/runtime/server/render/astro/instance.ts b/packages/astro/src/runtime/server/render/astro/instance.ts
index 06f2706b3..7502d30a7 100644
--- a/packages/astro/src/runtime/server/render/astro/instance.ts
+++ b/packages/astro/src/runtime/server/render/astro/instance.ts
@@ -37,6 +37,7 @@ export class AstroComponentInstance {
 	}
 
 	async init(result: SSRResult) {
+		if (this.returnValue !== undefined) return this.returnValue;
 		this.returnValue = this.factory(result, this.props, this.slotValues);
 		return this.returnValue;
 	}
@@ -72,7 +73,7 @@ function validateComponentProps(props: any, displayName: string) {
 	}
 }
 
-export async function createAstroComponentInstance(
+export function createAstroComponentInstance(
 	result: SSRResult,
 	displayName: string,
 	factory: AstroComponentFactory,
@@ -81,16 +82,9 @@ export async function createAstroComponentInstance(
 ) {
 	validateComponentProps(props, displayName);
 	const instance = new AstroComponentInstance(result, props, slots, factory);
-
 	if (isAPropagatingComponent(result, factory) && !result._metadata.propagators.has(factory)) {
 		result._metadata.propagators.set(factory, instance);
-		// Call component instances that might have head content to be propagated up.
-		const returnValue = await instance.init(result);
-		if (isHeadAndContent(returnValue)) {
-			result._metadata.extraHead.push(returnValue.head);
-		}
 	}
-
 	return instance;
 }
 
diff --git a/packages/astro/src/runtime/server/render/astro/render.ts b/packages/astro/src/runtime/server/render/astro/render.ts
index 0cb7d43fa..0c34ef98d 100644
--- a/packages/astro/src/runtime/server/render/astro/render.ts
+++ b/packages/astro/src/runtime/server/render/astro/render.ts
@@ -71,12 +71,12 @@ export async function renderToReadableStream(
 	// If the Astro component returns a Response on init, return that response
 	if (templateResult instanceof Response) return templateResult;
 
+	let renderedFirstPageChunk = false;
+
 	if (isPage) {
 		await bufferHeadContent(result);
 	}
 
-	let renderedFirstPageChunk = false;
-
 	return new ReadableStream({
 		start(controller) {
 			const destination: RenderDestination = {
@@ -158,6 +158,7 @@ async function bufferHeadContent(result: SSRResult) {
 		if (done) {
 			break;
 		}
+		// Call component instances that might have head content to be propagated up.
 		const returnValue = await value.init(result);
 		if (isHeadAndContent(returnValue)) {
 			result._metadata.extraHead.push(returnValue.head);
diff --git a/packages/astro/src/runtime/server/render/component.ts b/packages/astro/src/runtime/server/render/component.ts
index dcd4b562c..33de90a26 100644
--- a/packages/astro/src/runtime/server/render/component.ts
+++ b/packages/astro/src/runtime/server/render/component.ts
@@ -420,7 +420,7 @@ async function renderAstroComponent(
 	props: Record<string | number, any>,
 	slots: any = {}
 ): Promise<RenderInstance> {
-	const instance = await createAstroComponentInstance(result, displayName, Component, props, slots);
+	const instance = createAstroComponentInstance(result, displayName, Component, props, slots);
 
 	// Eagerly render the component so they are rendered in parallel
 	const chunks: RenderDestinationChunk[] = [];
diff --git a/packages/astro/src/runtime/server/render/index.ts b/packages/astro/src/runtime/server/render/index.ts
index 4760e07b7..70d63ca60 100644
--- a/packages/astro/src/runtime/server/render/index.ts
+++ b/packages/astro/src/runtime/server/render/index.ts
@@ -6,6 +6,6 @@ export { renderHTMLElement } from './dom.js';
 export { maybeRenderHead, renderHead } from './head.js';
 export { renderPage } from './page.js';
 export { renderSlot, renderSlotToString, type ComponentSlots } from './slot.js';
-export { renderScriptElement, renderUniqueScriptElement, renderUniqueStylesheet } from './tags.js';
+export { renderScriptElement, renderUniqueStylesheet } from './tags.js';
 export type { RenderInstruction } from './types';
 export { addAttribute, defineScriptVars, voidElementNames } from './util.js';
diff --git a/packages/astro/src/runtime/server/render/tags.ts b/packages/astro/src/runtime/server/render/tags.ts
index 00a734814..f15da6571 100644
--- a/packages/astro/src/runtime/server/render/tags.ts
+++ b/packages/astro/src/runtime/server/render/tags.ts
@@ -9,45 +9,14 @@ export function renderScriptElement({ props, children }: SSRElement) {
 	});
 }
 
-export function renderUniqueScriptElement(result: SSRResult, { props, children }: SSRElement) {
-	if (
-		Array.from(result.scripts).some((s) => {
-			if (s.props.type === props.type && s.props.src === props.src) {
-				return true;
-			}
-			if (!props.src && s.children === children) return true;
-		})
-	)
-		return '';
-	const key = `script-${props.type}-${props.src}-${children}`;
-	if (checkOrAddContentKey(result, key)) return '';
-	return renderScriptElement({ props, children });
-}
-
 export function renderUniqueStylesheet(result: SSRResult, sheet: StylesheetAsset) {
 	if (sheet.type === 'external') {
 		if (Array.from(result.styles).some((s) => s.props.href === sheet.src)) return '';
-		const key = 'link-external-' + sheet.src;
-		if (checkOrAddContentKey(result, key)) return '';
-		return renderElement('link', {
-			props: {
-				rel: 'stylesheet',
-				href: sheet.src,
-			},
-			children: '',
-		});
+		return renderElement('link', { props: { rel: 'stylesheet', href: sheet.src }, children: '' });
 	}
 
 	if (sheet.type === 'inline') {
 		if (Array.from(result.styles).some((s) => s.children.includes(sheet.content))) return '';
-		const key = `link-inline-` + sheet.content;
-		if (checkOrAddContentKey(result, key)) return '';
 		return renderElement('style', { props: { type: 'text/css' }, children: sheet.content });
 	}
 }
-
-function checkOrAddContentKey(result: SSRResult, key: string): boolean {
-	if (result._metadata.contentKeys.has(key)) return true;
-	result._metadata.contentKeys.add(key);
-	return false;
-}