Fix issue where a message that errors out creates a bad state

web/src/app/chat/Chat.tsx

@@ -18,6 +18,7 @@ import {
   createChatSession,
   getCitedDocumentsFromMessage,
   getHumanAndAIMessageFromMessageNumber,
+  getLastSuccessfulMessageId,
   handleAutoScroll,
   handleChatFeedback,
   nameChatSession,
@@ -205,12 +206,11 @@ export const Chat = ({
     let error: string | null = null;
     let finalMessage: BackendMessage | null = null;
     try {
+      const lastSuccessfulMessageId =
+        getLastSuccessfulMessageId(currMessageHistory);
       for await (const packetBunch of sendMessage({
         message: currMessage,
-        parentMessageId:
+        parentMessageId: lastSuccessfulMessageId,
-          currMessageHistory.length > 0
-            ? currMessageHistory[currMessageHistory.length - 1].messageId
-            : null,
         chatSessionId: currChatSessionId,
         // if search-only set prompt to null to tell backend to not give an answer
         promptId:

web/src/app/chat/lib.tsx

@@ -266,3 +266,16 @@ export function groupSessionsByDateRange(chatSessions: ChatSession[]) {
 
   return groups;
 }
+
+export function getLastSuccessfulMessageId(messageHistory: Message[]) {
+  const lastSuccessfulMessage = messageHistory
+    .slice()
+    .reverse()
+    .find(
+      (message) =>
+        message.type === "assistant" &&
+        message.messageId !== -1 &&
+        message.messageId !== null
+    );
+  return lastSuccessfulMessage ? lastSuccessfulMessage?.messageId : null;
+}

web/src/lib/search/streamingQa.ts

@@ -34,9 +34,9 @@ export const searchRequestStreamed = async ({
     const filters = buildFilters(sources, documentSets, timeRange);
 
     const threadMessage = {
-        message: query,
+      message: query,
-        sender: null,
+      sender: null,
-        role: "user"
+      role: "user",
     };
 
     const response = await fetch("/api/query/stream-answer-with-quote", {