docs: harden Ask AI retrieval + fix stale loading state

- searchDocs: wrap the keyword query in try/catch too, so each retrieval path
  (keyword, vector) is independent best-effort
- ask-ai: gate the loading ellipsis to the in-progress (last) message so older
  empty bubbles don't re-show it while a later request streams

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ouiliame

apps/docs/app/api/chat/route.ts

@@ -216,16 +216,23 @@ type SearchRow = {
 async function searchDocs(query: string, locale: string) {
   const tsConfig = TS_CONFIG[locale] ?? 'simple'
 
-  const keywordRows = await db
-    .select(SEARCH_COLUMNS)
-    .from(docsEmbeddings)
-    .where(
-      sql`${docsEmbeddings.chunkTextTsv} @@ plainto_tsquery(${tsConfig}, ${query}) and ${localeFilter(locale)}`
-    )
-    .orderBy(
-      sql`ts_rank(${docsEmbeddings.chunkTextTsv}, plainto_tsquery(${tsConfig}, ${query})) DESC`
-    )
-    .limit(SEARCH_CANDIDATES)
+  // Each retrieval path is best-effort and independent: a failure in one still
+  // lets the other ground the answer (both empty just yields no grounding).
+  let keywordRows: SearchRow[] = []
+  try {
+    keywordRows = await db
+      .select(SEARCH_COLUMNS)
+      .from(docsEmbeddings)
+      .where(
+        sql`${docsEmbeddings.chunkTextTsv} @@ plainto_tsquery(${tsConfig}, ${query}) and ${localeFilter(locale)}`
+      )
+      .orderBy(
+        sql`ts_rank(${docsEmbeddings.chunkTextTsv}, plainto_tsquery(${tsConfig}, ${query})) DESC`
+      )
+      .limit(SEARCH_CANDIDATES)
+  } catch (error) {
+    console.error('Ask AI keyword search failed:', error)
+  }
 
   let vectorRows: SearchRow[] = []
   if (locale === DEFAULT_LOCALE) {

apps/docs/components/ai/ask-ai.tsx

@@ -118,8 +118,10 @@ export function AskAI({ locale }: AskAIProps) {
               </p>
             )}
 
-            {messages.map((message) => {
+            {messages.map((message, index) => {
               const text = getText(message.parts)
+              // Only the in-progress (last) message should show the loading state.
+              const isStreaming = isBusy && index === messages.length - 1
               const sources = message.role === 'assistant' ? getSources(message.parts) : []
               return (
                 <div
@@ -139,7 +141,7 @@ export function AskAI({ locale }: AskAIProps) {
                         <Streamdown className='space-y-2 text-sm leading-relaxed [&_a]:text-[var(--text-link)] [&_a]:underline [&_li]:my-0.5 [&_ol]:list-decimal [&_ol]:pl-5 [&_ul]:list-disc [&_ul]:pl-5'>
                           {text}
                         </Streamdown>
-                      ) : isBusy ? (
+                      ) : isStreaming ? (
                         '…'
                       ) : sources.length === 0 ? (
                         <span className='text-[var(--text-muted)]'>No answer returned.</span>