Fixes: Chatbot crashes when given empty url following http:// or https:// (#7138)

* link fix

* add changeset

* add unit test

* format

---------

Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>

.changeset/curly-feet-win.md

@@ -0,0 +1,6 @@
+---
+"@gradio/markdown": patch
+"gradio": patch
+---
+
+fix:Fixes: Chatbot crashes when given empty url following http:// or https://

js/markdown/Markdown.test.ts

@@ -0,0 +1,52 @@
+import { test, describe, assert, afterEach } from "vitest";
+import { cleanup, render } from "@gradio/tootils";
+
+import Markdown from "./Index.svelte";
+import type { LoadingStatus } from "@gradio/statustracker";
+
+const loading_status: LoadingStatus = {
+	eta: 0,
+	queue_position: 1,
+	queue_size: 1,
+	status: "complete" as LoadingStatus["status"],
+	scroll_to_output: false,
+	visible: true,
+	fn_index: 0,
+	show_progress: "full"
+};
+
+describe("Markdown", () => {
+	afterEach(() => cleanup());
+
+	test("renders valid URL", async () => {
+		const { getByText } = await render(Markdown, {
+			show_label: true,
+			max_lines: 1,
+			loading_status,
+			lines: 1,
+			value: "Visit [Gradio](https://www.gradio.app/) for more information.",
+			label: "Markdown",
+			interactive: false
+		});
+
+		const link: HTMLAnchorElement = getByText("Gradio") as HTMLAnchorElement;
+		assert.equal(link.href, "https://www.gradio.app/");
+	});
+
+	test("renders invalid URL", async () => {
+		const { getByText } = await render(Markdown, {
+			show_label: true,
+			max_lines: 1,
+			loading_status,
+			lines: 1,
+			value: "Visit [Invalid URL](https://) for more information.",
+			label: "Markdown",
+			interactive: false
+		});
+
+		const link: HTMLAnchorElement = getByText(
+			"Invalid URL"
+		) as HTMLAnchorElement;
+		assert.equal(link.href, "https://");
+	});
+});

js/markdown/shared/MarkdownCode.svelte

@@ -27,8 +27,13 @@
 		line_breaks
 	});
 
-	const is_external_url = (link: string | null): boolean =>
-		!!(link && new URL(link, location.href).origin !== location.origin);
+	const is_external_url = (link: string | null): boolean => {
+		try {
+			return !!link && new URL(link, location.href).origin !== location.origin;
+		} catch (e) {
+			return false;
+		}
+	};
 
 	DOMPurify.addHook("afterSanitizeAttributes", function (node) {
 		if ("target" in node) {