4 files changed, 41 insertions, 20 deletions
diff --git a/packages/integrations/lit/package.json b/packages/integrations/lit/package.json
index 8ad1a5279..19892743d 100644
--- a/packages/integrations/lit/package.json
+++ b/packages/integrations/lit/package.json
@@ -34,7 +34,8 @@
     "test": "mocha"
   },
   "dependencies": {
-    "@lit-labs/ssr": "^2.2.0",
+    "@lit-labs/ssr": "^3.1.0",
+    "@lit-labs/ssr-dom-shim": "^1.1.0",
     "parse5": "^7.1.2"
   },
   "devDependencies": {
@@ -42,12 +43,12 @@
     "astro-scripts": "workspace:*",
     "chai": "^4.3.6",
     "cheerio": "^1.0.0-rc.11",
-    "lit": "^2.2.5",
+    "lit": "^2.7.0",
     "mocha": "^9.2.2",
     "sass": "^1.52.2"
   },
   "peerDependencies": {
-    "@webcomponents/template-shadowroot": "^0.1.0",
-    "lit": "^2.1.3"
+    "@webcomponents/template-shadowroot": "^0.2.1",
+    "lit": "^2.7.0"
   }
 }
diff --git a/packages/integrations/lit/server-shim.js b/packages/integrations/lit/server-shim.js
index 3f4a8df4f..ed371f89a 100644
--- a/packages/integrations/lit/server-shim.js
+++ b/packages/integrations/lit/server-shim.js
@@ -1,20 +1,35 @@
-import { installWindowOnGlobal } from '@lit-labs/ssr/lib/dom-shim.js';
+import { customElements as litCE, HTMLElement as litShimHTMLElement } from '@lit-labs/ssr-dom-shim';
 
-if (typeof fetch === 'function') {
-	const _fetch = fetch;
-	installWindowOnGlobal();
-	globalThis.fetch = window.fetch = _fetch;
-} else {
-	installWindowOnGlobal();
+// Something at build time injects document.currentScript = undefined instead of
+// document.currentScript = null. This causes Sass build to fail because it
+// seems to be expecting `=== null`. This set to `undefined` doesn't seem to be
+// caused by Lit and only happens at build / test time, but not in dev or
+// preview time.
+if (globalThis.document) {
+	document.currentScript = null;
 }
 
-window.global = window;
-document.getElementsByTagName = () => [];
-// See https://github.com/lit/lit/issues/2393
-document.currentScript = null;
+if (globalThis.HTMLElement) {
+	// Seems Astro's Element shim does nothing when `.setAttribute` is called
+	// and subsequently `.getAttribute` is called. Causes Lit to not SSR attrs
+	globalThis.HTMLElement = litShimHTMLElement;
+}
+
+// Astro seems to have a DOM shim and the only real difference that we need out
+// of the Lit DOM shim is that the Lit DOM shim reads
+// `HTMLElement.observedAttributes` which is meant to trigger
+// `ReactiveElement.finalize()`. So this is the only thing we will re-shim since
+// Lit will try to respect other global DOM shims.
+globalThis.customElements = litCE;
+
+const litCeDefine = customElements.define;
 
-const ceDefine = customElements.define;
+// We need to patch customElements.define to keep track of the tagName on the
+// class itself so that we can transform JSX custom element class definintion to
+// a DSD string on the server, because there is no way to get the tagName from a
+// CE class otherwise. Not an issue on client:only because the browser supports
+// appending a class instance directly to the DOM.
 customElements.define = function (tagName, Ctr) {
 	Ctr[Symbol.for('tagName')] = tagName;
-	return ceDefine.call(this, tagName, Ctr);
+	return litCeDefine.call(this, tagName, Ctr);
 };
diff --git a/packages/integrations/lit/server.js b/packages/integrations/lit/server.js
index ae89bd610..762c77844 100644
--- a/packages/integrations/lit/server.js
+++ b/packages/integrations/lit/server.js
@@ -1,5 +1,4 @@
 import './server-shim.js';
-import '@lit-labs/ssr/lib/render-lit-html.js';
 import { LitElementRenderer } from '@lit-labs/ssr/lib/lit-element-renderer.js';
 import * as parse5 from 'parse5';
 
diff --git a/packages/integrations/lit/test/server.test.js b/packages/integrations/lit/test/server.test.js
index 315937401..51e083241 100644
--- a/packages/integrations/lit/test/server.test.js
+++ b/packages/integrations/lit/test/server.test.js
@@ -1,6 +1,8 @@
 import { expect } from 'chai';
-import server from '../server.js';
 import { LitElement, html } from 'lit';
+// Must come after lit import because @lit/reactive-element defines
+// globalThis.customElements which the server shim expects to be defined.
+import server from '../server.js';
 import * as cheerio from 'cheerio';
 
 const { check, renderToStaticMarkup } = server;
@@ -12,6 +14,10 @@ describe('check', () => {
 
 	it('should be false with a registered non-lit component', async () => {
 		const tagName = 'non-lit-component';
+		// Lit no longer shims HTMLElement globally, so we need to do it ourselves.
+		if (!globalThis.HTMLElement) {
+			globalThis.HTMLElement = class {};
+		}
 		customElements.define(tagName, class TestComponent extends HTMLElement {});
 		expect(await check(tagName)).to.equal(false);
 	});
@@ -85,7 +91,7 @@ describe('renderToStaticMarkup', () => {
 	});
 
 	it('should render DSD attributes based on shadowRootOptions', async () => {
-		const tagName = 'lit-component';
+		const tagName = 'shadow-root-options-component';
 		customElements.define(
 			tagName,
 			class extends LitElement {