fix(ai): keep replies visible on legacy WebView

apps/desktop/src/lib/__tests__/ai/aiMessageRender.spec.ts

@@ -80,6 +80,26 @@ describe("createAiMessageRenderer", () => {
     expect(code).toMatchObject({ type: "code", pending: false, html: "<span>SELECT 1</span>" });
   });
 
+  it("falls back to escaped code when highlighting is not supported", () => {
+    const markdown = (text: string) => `<p>${text}</p>`;
+    const highlightCode = vi.fn(() => {
+      throw new SyntaxError("Invalid regular expression: invalid group specifier name");
+    });
+    const renderer = createAiMessageRenderer({ markdown, highlightCode });
+
+    const [code] = renderer.render("```sql\nSELECT < 1\n```");
+
+    expect(highlightCode).toHaveBeenCalledWith("SELECT < 1", "SQL");
+    expect(code).toEqual({
+      type: "code",
+      content: "SELECT < 1",
+      html: "SELECT &lt; 1",
+      lang: "SQL",
+      isSql: true,
+      pending: false,
+    });
+  });
+
   it("re-parses only the last paragraph of a long streaming answer", () => {
     const markdown = vi.fn((text: string) => `<p>${text}</p>`);
     const renderer = createAiMessageRenderer({ markdown });

apps/desktop/src/lib/ai/aiMessageRender.ts

@@ -97,7 +97,7 @@ export function createAiMessageRenderer(options: AiMessageRendererOptions) {
     }
     const lang = normalizeAiCodeLanguage(segment.lang);
     // Highlighting a block that is still streaming is wasted work: it is re-highlighted once the fence closes.
-    const highlighted = flags.live && flags.pending ? undefined : options.highlightCode?.(segment.content, lang);
+    const highlighted = flags.live && flags.pending ? undefined : safeHighlightCode(segment.content, lang);
     return {
       type: "code",
       content: segment.content,
@@ -108,6 +108,15 @@ export function createAiMessageRenderer(options: AiMessageRendererOptions) {
     };
   }
 
+  function safeHighlightCode(content: string, lang: string): string | undefined {
+    if (!options.highlightCode) return undefined;
+    try {
+      return options.highlightCode(content, lang);
+    } catch {
+      return undefined;
+    }
+  }
+
   function renderCachedSegment(segment: MessageSegment, flags: SegmentRenderFlags): AiMessageRenderSegment {
     if (segment.content.length > maxCacheableChars) return renderSegment(segment, flags);
 

apps/desktop/src/lib/backend/tauri.ts

@@ -441,6 +441,10 @@ export type AgentEvent =
     }
   | { type: "error"; message: string };
 
+type TauriAgentEvent = AgentEvent & {
+  session_id?: string;
+};
+
 export async function aiAgentStream(
   sessionId: string,
   request: AiCompletionRequest,
@@ -457,9 +461,11 @@ export async function aiAgentStream(
   confirmedSchema?: string,
   _signal?: AbortSignal,
 ): Promise<string> {
-  const unlisten: UnlistenFn = await listen<AgentEvent>("ai-agent-event", (event) => {
-    onEvent(event.payload);
-    if (event.payload.type === "agent_end" || event.payload.type === "error") {
+  const unlisten: UnlistenFn = await listen<TauriAgentEvent>("ai-agent-event", (event) => {
+    const payload = event.payload;
+    if (payload.session_id && payload.session_id !== sessionId) return;
+    onEvent(payload);
+    if (payload.type === "agent_end" || payload.type === "error") {
       unlisten();
     }
   });