fix(app): terminal pty isolation

3 files changed, 66 insertions, 2 deletions

diff --git a/packages/app/src/components/terminal.tsx b/packages/app/src/components/terminal.tsx
index f6bb0b48a..ccf7012d2 100644
--- a/packages/app/src/components/terminal.tsx
+++ b/packages/app/src/components/terminal.tsx
@@ -10,6 +10,7 @@ import { resolveThemeVariant, useTheme, withAlpha, type HexColor } from "@openco
 import { useLanguage } from "@/context/language"
 import { showToast } from "@opencode-ai/ui/toast"
 import { disposeIfDisposable, getHoveredLinkText, setOptionIfSupported } from "@/utils/runtime-adapters"
+import { terminalWriter } from "@/utils/terminal-writer"
 
 const TOGGLE_TERMINAL_ID = "terminal.toggle"
 const DEFAULT_TOGGLE_TERMINAL_KEYBIND = "ctrl+`"
@@ -160,6 +161,7 @@ export const Terminal = (props: TerminalProps) => {
   const start =
     typeof local.pty.cursor === "number" && Number.isSafeInteger(local.pty.cursor) ? local.pty.cursor : undefined
   let cursor = start ?? 0
+  let output: ReturnType<typeof terminalWriter> | undefined
 
   const cleanup = () => {
     if (!cleanups.length) return
@@ -300,7 +302,7 @@ export const Terminal = (props: TerminalProps) => {
         fontSize: 14,
         fontFamily: monoFontFamily(settings.appearance.font()),
         allowTransparency: false,
-        convertEol: true,
+        convertEol: false,
         theme: terminalColors(),
         scrollback: 10_000,
         ghostty: g,
@@ -312,6 +314,7 @@ export const Terminal = (props: TerminalProps) => {
       }
       ghostty = g
       term = t
+      output = terminalWriter((data) => t.write(data))
 
       t.attachCustomKeyEventHandler((event) => {
         const key = event.key.toLowerCase()
@@ -416,7 +419,7 @@ export const Terminal = (props: TerminalProps) => {
 
         const data = typeof event.data === "string" ? event.data : ""
         if (!data) return
-        t.write(data)
+        output?.push(data)
         cursor += data.length
       }
       socket.addEventListener("message", handleMessage)
@@ -459,6 +462,7 @@ export const Terminal = (props: TerminalProps) => {
 
   onCleanup(() => {
     disposed = true
+    output?.flush()
     persistTerminal({ term, addon: serializeAddon, cursor, pty: local.pty, onCleanup: props.onCleanup })
     cleanup()
   })
diff --git a/packages/app/src/utils/terminal-writer.test.ts b/packages/app/src/utils/terminal-writer.test.ts
new file mode 100644
index 000000000..d48dd4f4e
--- /dev/null
+++ b/packages/app/src/utils/terminal-writer.test.ts
@@ -0,0 +1,33 @@
+import { describe, expect, test } from "bun:test"
+import { terminalWriter } from "./terminal-writer"
+
+describe("terminalWriter", () => {
+  test("buffers and flushes once per schedule", () => {
+    const calls: string[] = []
+    const scheduled: VoidFunction[] = []
+    const writer = terminalWriter(
+      (data) => calls.push(data),
+      (flush) => scheduled.push(flush),
+    )
+
+    writer.push("a")
+    writer.push("b")
+    writer.push("c")
+
+    expect(calls).toEqual([])
+    expect(scheduled).toHaveLength(1)
+
+    scheduled[0]?.()
+    expect(calls).toEqual(["abc"])
+  })
+
+  test("flush is a no-op when empty", () => {
+    const calls: string[] = []
+    const writer = terminalWriter(
+      (data) => calls.push(data),
+      (flush) => flush(),
+    )
+    writer.flush()
+    expect(calls).toEqual([])
+  })
+})
diff --git a/packages/app/src/utils/terminal-writer.ts b/packages/app/src/utils/terminal-writer.ts
new file mode 100644
index 000000000..b6caff789
--- /dev/null
+++ b/packages/app/src/utils/terminal-writer.ts
@@ -0,0 +1,27 @@
+export function terminalWriter(
+  write: (data: string) => void,
+  schedule: (flush: VoidFunction) => void = queueMicrotask,
+) {
+  let chunks: string[] | undefined
+  let scheduled = false
+
+  const flush = () => {
+    scheduled = false
+    const items = chunks
+    if (!items?.length) return
+    chunks = undefined
+    write(items.join(""))
+  }
+
+  const push = (data: string) => {
+    if (!data) return
+    if (chunks) chunks.push(data)
+    else chunks = [data]
+
+    if (scheduled) return
+    scheduled = true
+    schedule(flush)
+  }
+
+  return { push, flush }
+}