fix(app): terminal cross-talk (#14184)

3 files changed, 86 insertions, 19 deletions

diff --git a/packages/opencode/src/pty/index.ts b/packages/opencode/src/pty/index.ts
index a9052a79e..c98e99daf 100644
--- a/packages/opencode/src/pty/index.ts
+++ b/packages/opencode/src/pty/index.ts
@@ -18,18 +18,24 @@ export namespace Pty {
 
   type Socket = {
     readyState: number
+    data: object
     send: (data: string | Uint8Array<ArrayBuffer> | ArrayBuffer) => void
     close: (code?: number, reason?: string) => void
   }
 
-  const sockets = new WeakMap<object, number>()
-  let socketCounter = 0
+  // Bun's ServerWebSocket has a per-connection `.data` object (set during
+  // `server.upgrade`) that changes when the underlying connection is recycled.
+  // We keep a reference to a stable part of it so output can't leak even when
+  // websocket objects are reused.
+  const token = (ws: Socket) => {
+    const data = ws.data
+    const events = (data as { events?: unknown }).events
+    if (events && typeof events === "object") return events
 
-  const tagSocket = (ws: Socket) => {
-    if (!ws || typeof ws !== "object") return
-    const next = (socketCounter = (socketCounter + 1) % Number.MAX_SAFE_INTEGER)
-    sockets.set(ws, next)
-    return next
+    const url = (data as { url?: unknown }).url
+    if (url && typeof url === "object") return url
+
+    return data
   }
 
   // WebSocket control frame: 0x00 + UTF-8 JSON (currently { cursor }).
@@ -96,7 +102,7 @@ export namespace Pty {
     buffer: string
     bufferCursor: number
     cursor: number
-    subscribers: Map<Socket, number>
+    subscribers: Map<Socket, object>
   }
 
   const state = Instance.state(
@@ -176,26 +182,27 @@ export namespace Pty {
       subscribers: new Map(),
     }
     state().set(id, session)
-    ptyProcess.onData((data) => {
-      session.cursor += data.length
+    ptyProcess.onData((chunk) => {
+      session.cursor += chunk.length
 
-      for (const [ws, id] of session.subscribers) {
+      for (const [ws, data] of session.subscribers) {
         if (ws.readyState !== 1) {
           session.subscribers.delete(ws)
           continue
         }
-        if (typeof ws === "object" && sockets.get(ws) !== id) {
+
+        if (token(ws) !== data) {
           session.subscribers.delete(ws)
           continue
         }
         try {
-          ws.send(data)
+          ws.send(chunk)
         } catch {
           session.subscribers.delete(ws)
         }
       }
 
-      session.buffer += data
+      session.buffer += chunk
       if (session.buffer.length <= BUFFER_LIMIT) return
       const excess = session.buffer.length - BUFFER_LIMIT
       session.buffer = session.buffer.slice(excess)
@@ -305,8 +312,12 @@ export namespace Pty {
       return
     }
 
-    const socketId = tagSocket(ws)
-    if (typeof socketId === "number") session.subscribers.set(ws, socketId)
+    if (!ws.data || typeof ws.data !== "object") {
+      ws.close()
+      return
+    }
+
+    session.subscribers.set(ws, token(ws))
     return {
       onMessage: (message: string | ArrayBuffer) => {
         session.process.write(String(message))
diff --git a/packages/opencode/src/server/routes/pty.ts b/packages/opencode/src/server/routes/pty.ts
index 21156190d..d516859f7 100644
--- a/packages/opencode/src/server/routes/pty.ts
+++ b/packages/opencode/src/server/routes/pty.ts
@@ -163,6 +163,7 @@ export const PtyRoutes = lazy(() =>
 
         type Socket = {
           readyState: number
+          data: object
           send: (data: string | Uint8Array<ArrayBuffer> | ArrayBuffer) => void
           close: (code?: number, reason?: string) => void
         }
@@ -170,6 +171,10 @@ export const PtyRoutes = lazy(() =>
         const isSocket = (value: unknown): value is Socket => {
           if (!value || typeof value !== "object") return false
           if (!("readyState" in value)) return false
+          if (!("data" in value)) return false
+          if (!((value as { data?: unknown }).data && typeof (value as { data?: unknown }).data === "object")) {
+            return false
+          }
           if (!("send" in value) || typeof (value as { send?: unknown }).send !== "function") return false
           if (!("close" in value) || typeof (value as { close?: unknown }).close !== "function") return false
           return typeof (value as { readyState?: unknown }).readyState === "number"
@@ -177,11 +182,16 @@ export const PtyRoutes = lazy(() =>
 
         return {
           onOpen(_event, ws) {
-            const socket = isSocket(ws.raw) ? ws.raw : ws
-            handler = Pty.connect(id, socket, cursor)
+            const raw = ws.raw
+            if (!isSocket(raw)) {
+              ws.close()
+              return
+            }
+            handler = Pty.connect(id, raw, cursor)
           },
           onMessage(event) {
-            handler?.onMessage(String(event.data))
+            if (typeof event.data !== "string") return
+            handler?.onMessage(event.data)
           },
           onClose() {
             handler?.onClose()
diff --git a/packages/opencode/test/pty/pty-output-isolation.test.ts b/packages/opencode/test/pty/pty-output-isolation.test.ts
index b80d37345..337280d18 100644
--- a/packages/opencode/test/pty/pty-output-isolation.test.ts
+++ b/packages/opencode/test/pty/pty-output-isolation.test.ts
@@ -18,6 +18,7 @@ describe("pty", () => {
 
           const ws = {
             readyState: 1,
+            data: { events: { connection: "a" } },
             send: (data: unknown) => {
               outA.push(typeof data === "string" ? data : Buffer.from(data as Uint8Array).toString("utf8"))
             },
@@ -30,6 +31,7 @@ describe("pty", () => {
           Pty.connect(a.id, ws as any)
 
           // Now "reuse" the same ws object for another connection.
+          ws.data = { events: { connection: "b" } }
           ws.send = (data: unknown) => {
             outB.push(typeof data === "string" ? data : Buffer.from(data as Uint8Array).toString("utf8"))
           }
@@ -51,4 +53,48 @@ describe("pty", () => {
       },
     })
   })
+
+  test("does not leak output when Bun recycles websocket objects before re-connect", async () => {
+    await using dir = await tmpdir({ git: true })
+
+    await Instance.provide({
+      directory: dir.path,
+      fn: async () => {
+        const a = await Pty.create({ command: "cat", title: "a" })
+        try {
+          const outA: string[] = []
+          const outB: string[] = []
+
+          const ws = {
+            readyState: 1,
+            data: { events: { connection: "a" } },
+            send: (data: unknown) => {
+              outA.push(typeof data === "string" ? data : Buffer.from(data as Uint8Array).toString("utf8"))
+            },
+            close: () => {
+              // no-op (simulate abrupt drop)
+            },
+          }
+
+          // Connect "a" first.
+          Pty.connect(a.id, ws as any)
+          outA.length = 0
+
+          // Simulate Bun reusing the same websocket object for another connection
+          // before the new onOpen handler has a chance to tag it.
+          ws.data = { events: { connection: "b" } }
+          ws.send = (data: unknown) => {
+            outB.push(typeof data === "string" ? data : Buffer.from(data as Uint8Array).toString("utf8"))
+          }
+
+          Pty.write(a.id, "AAA\n")
+          await Bun.sleep(100)
+
+          expect(outB.join("")).not.toContain("AAA")
+        } finally {
+          await Pty.remove(a.id)
+        }
+      },
+    })
+  })
 })