Align terminal stream with snapshot-only attach

packages/server/src/terminal/terminal.test.ts

@@ -438,6 +438,31 @@ describe("Terminal", () => {
       unsubscribe();
     });
 
+    it("emits output only after getState reflects the new data", async () => {
+      const session = trackSession(
+        await createTerminal({
+          cwd: "/tmp",
+          shell: "/bin/sh",
+          env: { PS1: "$ " },
+        }),
+      );
+
+      await waitForLines(session, ["$"]);
+      const outputSeenInState = new Promise<boolean>((resolve) => {
+        const unsubscribe = session.subscribe((message) => {
+          if (message.type !== "output" || !message.data.includes("state-after-output")) {
+            return;
+          }
+          unsubscribe();
+          const stateText = getLines(session.getState()).join("\n");
+          resolve(stateText.includes("state-after-output"));
+        });
+      });
+
+      session.send({ type: "input", data: "echo state-after-output\r" });
+      expect(await outputSeenInState).toBe(true);
+    });
+
     it("unsubscribe stops receiving messages", async () => {
       const session = trackSession(
         await createTerminal({

packages/server/src/terminal/terminal.ts

@@ -322,10 +322,13 @@ export async function createTerminal(options: CreateTerminalOptions): Promise<Te
   // Pipe PTY output to terminal emulator
   ptyProcess.onData((data) => {
     if (killed) return;
-    for (const listener of listeners) {
-      listener({ type: "output", data });
-    }
     terminal.write(data, () => {
+      if (disposed || killed) {
+        return;
+      }
+      for (const listener of listeners) {
+        listener({ type: "output", data });
+      }
       scheduleStateBroadcast();
     });
   });
@@ -359,6 +362,7 @@ export async function createTerminal(options: CreateTerminalOptions): Promise<Te
       case "resize":
         terminal.resize(msg.cols, msg.rows);
         ptyProcess.resize(msg.cols, msg.rows);
+        scheduleStateBroadcast();
         break;
       case "mouse":
         // Mouse events can be sent as escape sequences if terminal supports it
@@ -370,8 +374,8 @@ export async function createTerminal(options: CreateTerminalOptions): Promise<Te
   function subscribe(listener: (msg: ServerMessage) => void): () => void {
     listeners.add(listener);
 
-    queueMicrotask(() => {
-      if (listeners.has(listener)) {
+    terminal.write("", () => {
+      if (!disposed && listeners.has(listener)) {
         listener({ type: "snapshot", state: getState() });
       }
     });