Add additional scoping for head buffering (#6152)

* Add additional scoping for head buffering

* Add test for direct usage of nested component

* Add special scoping for Astro.scopes.render()

* Generate propagation map during the build

* Move to a maybeHead instruction

* Properly serialize for SSR

* More conservative scoping

* Maybe had should honor result._metadata.hasRenderedHead

* Properly type slots

* Allow template result to be passed

* Add changeset

1 files changed, 27 insertions, 0 deletions

diff --git a/packages/integrations/mdx/test/css-head-mdx.test.js b/packages/integrations/mdx/test/css-head-mdx.test.js
index 2b1dcdfe7..c38f23701 100644
--- a/packages/integrations/mdx/test/css-head-mdx.test.js
+++ b/packages/integrations/mdx/test/css-head-mdx.test.js
@@ -29,5 +29,32 @@ describe('Head injection w/ MDX', () => {
 			const scripts = document.querySelectorAll('head script[type=module]');
 			expect(scripts).to.have.a.lengthOf(1);
 		});
+
+		it('injects into the head for content collections', async () => {
+			const html = await fixture.readFile('/posts/test/index.html');
+			const { document } = parseHTML(html);
+
+			const links = document.querySelectorAll('head link[rel=stylesheet]');
+			expect(links).to.have.a.lengthOf(1);
+		});
+
+		it('injects content from a component using Content#render()', async () => {
+			const html = await fixture.readFile('/DirectContentUsage/index.html');
+			const { document } = parseHTML(html);
+
+			const links = document.querySelectorAll('head link[rel=stylesheet]');
+			expect(links).to.have.a.lengthOf(1);
+
+			const scripts = document.querySelectorAll('head script[type=module]');
+			expect(scripts).to.have.a.lengthOf(2);
+		});
+
+		it('Using component using slots.render() API', async () => {
+			const html = await fixture.readFile('/remote/index.html');
+			const { document } = parseHTML(html);
+
+			const links = document.querySelectorAll('head link[rel=stylesheet]');
+			expect(links).to.have.a.lengthOf(1);
+		});
 	});
 });