fix(core): restore Ctrl+C in Windows terminals (#47163)

packages/core/src/pty/pty.bun.ts

@@ -1,8 +1,24 @@
+import { dlopen } from "bun:ffi"
 import { spawn } from "bun-pty"
 import type { Opts, Proc } from "./pty.js"
 
 export type { Disp, Exit, Opts, Proc } from "./pty.js"
 
+if (process.platform === "win32") {
+  const library = dlopen("kernel32.dll", {
+    SetConsoleCtrlHandler: { args: ["ptr", "i32"], returns: "i32" },
+    GetLastError: { args: [], returns: "u32" },
+  })
+  try {
+    // Detached servers start with Ctrl+C ignored, and ConPTY shells inherit it.
+    // Clear that attribute once before spawning shells; keep registered handlers.
+    if (library.symbols.SetConsoleCtrlHandler(null, 0) === 0)
+      throw new Error(`Failed to enable PTY Ctrl+C handling: Windows error ${library.symbols.GetLastError()}`)
+  } finally {
+    library.close()
+  }
+}
+
 function spawnPty(file: string, args: string[], opts: Opts): Proc {
   const pty = spawn(file, args, opts)
   return {

packages/core/test/fixture/pty-windows.ts

@@ -0,0 +1,69 @@
+import assert from "node:assert/strict"
+import { spawn } from "../../src/pty/pty.bun"
+
+const raw = process.argv[2] === "raw"
+const pty = spawn(
+  Bun.which("pwsh") ?? "powershell.exe",
+  [
+    "-NoLogo",
+    "-NoProfile",
+    ...(raw ? [] : ["-NoExit"]),
+    "-Command",
+    raw
+      ? "[Console]::TreatControlCAsInput = $true; Write-Output 'PTY_RAW_READY'; $key = [Console]::ReadKey($true); Write-Output ('PTY_KEY:' + [int]$key.KeyChar)"
+      : "Remove-Module PSReadLine -ErrorAction SilentlyContinue; function prompt { 'PTY_PROMPT> ' }",
+  ],
+  { name: "xterm-256color", cols: 160, rows: 24, env: { ...process.env, TERM: "xterm-256color" } },
+)
+const output = { text: "", cursor: 0 }
+const listeners = new Set<() => void>()
+const exited = Promise.withResolvers<number>()
+pty.onExit((event) => exited.resolve(event.exitCode))
+pty.onData((text) => {
+  output.text += text
+  listeners.forEach((check) => check())
+})
+
+try {
+  if (raw) {
+    await waitFor("PTY_RAW_READY")
+    pty.write("\x03")
+    await waitFor("PTY_KEY:3")
+  }
+  if (!raw) {
+    await waitFor("PTY_PROMPT>")
+    // Split markers so echoed command text cannot satisfy the output checks.
+    pty.write("Write-Output ('PTY_' + 'BUSY'); Start-Sleep -Seconds 60; Write-Output ('PTY_' + 'COMPLETED')\r")
+    await waitFor("PTY_BUSY")
+    pty.write("\x03")
+    await waitFor("PTY_PROMPT>")
+    assert.ok(!output.text.includes("PTY_COMPLETED"))
+    pty.write("Write-Output ('PTY_' + 'REUSED')\r")
+    await waitFor("PTY_REUSED")
+    await waitFor("PTY_PROMPT>")
+    pty.write("exit 0\r")
+  }
+  assert.equal(await exited.promise, 0)
+} finally {
+  pty.kill()
+}
+process.exit(0)
+
+function waitFor(text: string) {
+  return new Promise<void>((resolve, reject) => {
+    const timeout = setTimeout(() => {
+      listeners.delete(check)
+      reject(new Error(`Timed out waiting for ${JSON.stringify(text)}: ${output.text}`))
+    }, 5_000)
+    const check = () => {
+      const index = output.text.indexOf(text, output.cursor)
+      if (index === -1) return
+      output.cursor = index + text.length
+      listeners.delete(check)
+      clearTimeout(timeout)
+      resolve()
+    }
+    listeners.add(check)
+    check()
+  })
+}

packages/core/test/pty/pty-windows.test.ts

@@ -0,0 +1,41 @@
+import { expect } from "bun:test"
+import { spawn } from "node:child_process"
+import path from "node:path"
+import { Effect } from "effect"
+import { it } from "../lib/effect"
+
+const windowsTest = process.platform === "win32" ? it.live : it.live.skip
+
+Array.of("interrupt", "raw").forEach((scenario) => {
+  windowsTest(
+    scenario === "interrupt"
+      ? "detached PTY hosts interrupt commands without closing the shell"
+      : "detached PTY hosts preserve Ctrl+C input for raw-mode programs",
+    Effect.gen(function* () {
+      // Isolate the inheritable Windows console state from the test runner.
+      const worker = yield* Effect.acquireRelease(
+        Effect.sync(() => {
+          const child = spawn(process.execPath, [path.join(import.meta.dir, "../fixture/pty-windows.ts"), scenario], {
+            detached: true,
+            stdio: ["ignore", "ignore", "pipe"],
+            timeout: 30_000,
+          })
+          const output: string[] = []
+          child.stderr.on("data", (chunk: Buffer) => output.push(chunk.toString()))
+          const exited = new Promise<number | null>((resolve, reject) => {
+            child.once("error", reject)
+            child.once("close", resolve)
+          })
+          return { child, output, exited }
+        }),
+        (worker) =>
+          Effect.sync(() => {
+            if (worker.child.exitCode === null && worker.child.signalCode === null) worker.child.kill()
+          }),
+      )
+      const code = yield* Effect.promise(() => worker.exited)
+      expect({ code, output: worker.output.join("") }).toEqual({ code: 0, output: "" })
+    }),
+    35_000,
+  )
+})