fix(spaces): keep Space emoji/colors stable on artifact re-deploy (#2378)

* fix(spaces): keep Space emoji/colors stable on artifact re-deploy

Re-deploying an existing artifact re-uploaded README.md, which buildReadme regenerates with a random emoji and gradient each time, so the Space's emoji/colors changed on every update. Only push index.html on update; the README (emoji, colors, title) is written once at creation. A genuine recreate (Space deleted on the Hub) still writes a fresh README.

* fix(spaces): seed Space emoji/colors deterministically instead of skipping README

Re-deploys keep a stable emoji/gradient because the README is seeded per artifact (conversationId:artifactIdentifier) rather than randomized, so re-uploading it on every deploy never reshuffles the Space. This also keeps index.html + README on both create and update paths, so a Space recovered from a failed first upload (the self-heal path) still gets its README/config. Verified against the Hub: a no-change re-upload is accepted as an empty commit, not an error.

Author: gary149

src/routes/api/v2/spaces/deploy/+server.ts

@@ -30,8 +30,19 @@ const bodySchema = z.object({
 const SPACE_EMOJIS = ["🚀", "✨", "🎨", "🤗", "💡", "🧩", "🌈", "⚡️", "🪄", "🔮", "🛸", "🎯"];
 const SPACE_COLORS = ["red", "yellow", "green", "blue", "indigo", "purple", "pink", "gray"];
 
-function pick<T>(arr: readonly T[]): T {
-	return arr[Math.floor(Math.random() * arr.length)];
+// Deterministic pick, seeded per artifact, so a Space keeps the same emoji and
+// gradient across re-deploys. A random pick would reshuffle them on every update
+// (the README is re-uploaded each deploy).
+function hashString(s: string): number {
+	let h = 0;
+	for (let i = 0; i < s.length; i++) {
+		h = (Math.imul(h, 31) + s.charCodeAt(i)) | 0;
+	}
+	return Math.abs(h);
+}
+
+function pick<T>(arr: readonly T[], seed: string): T {
+	return arr[hashString(seed) % arr.length];
 }
 
 function slugify(title: string): string {
@@ -45,7 +56,7 @@ function slugify(title: string): string {
 	return slug || "huggingchat-artifact";
 }
 
-function buildReadme(title: string): string {
+function buildReadme(title: string, seed: string): string {
 	const trimmed = title.slice(0, 200);
 	// YAML is a superset of JSON, so a JSON double-quoted string is a valid YAML
 	// double-quoted scalar with quotes, backslashes, control chars, and unicode
@@ -54,9 +65,9 @@ function buildReadme(title: string): string {
 	const headingTitle = trimmed.replace(/[\r\n]+/g, " ");
 	return `---
 title: ${yamlTitle}
-emoji: ${pick(SPACE_EMOJIS)}
-colorFrom: ${pick(SPACE_COLORS)}
-colorTo: ${pick(SPACE_COLORS)}
+emoji: ${pick(SPACE_EMOJIS, `${seed}:emoji`)}
+colorFrom: ${pick(SPACE_COLORS, `${seed}:from`)}
+colorTo: ${pick(SPACE_COLORS, `${seed}:to`)}
 sdk: static
 pinned: false
 tags:
@@ -124,14 +135,19 @@ export const POST: RequestHandler = async ({ locals, request }) => {
 		error(404, "Conversation not found");
 	}
 
+	// README emoji/colors are seeded per artifact so they stay identical across
+	// re-deploys; index.html + README are uploaded on every deploy (create and
+	// update), so a Space recovered from a failed first upload still gets its
+	// README/config, and re-deploying never reshuffles the Space's appearance.
+	const readmeSeed = `${body.conversationId}:${body.artifactIdentifier}`;
 	const files = [
 		{
 			path: "index.html",
 			content: new Blob([buildDeployableHtml(body.kind, body.content)], { type: "text/html" }),
 		},
 		{
 			path: "README.md",
-			content: new Blob([buildReadme(body.title)], { type: "text/markdown" }),
+			content: new Blob([buildReadme(body.title, readmeSeed)], { type: "text/markdown" }),
 		},
 	];