Fix setRawMode on Windows for non-stdin TTYs

src/js/node/tty.ts

@@ -8,6 +8,7 @@ const {
   isatty,
   getWindowSize: _getWindowSize,
 } = $cpp("ProcessBindingTTYWrap.cpp", "createBunTTYFunctions");
+const { TTY } = process.platform === "win32" ? process.binding("tty_wrap") : { TTY: undefined };
 
 const { validateInteger } = require("internal/validators");
 const fs = require("internal/fs/streams");
@@ -20,6 +21,14 @@ function ReadStream(fd): void {
   this.isRaw = false;
   // Only set isTTY to true if the fd is actually a TTY
   this.isTTY = isatty(fd);
+  if (process.platform === "win32" && fd !== 0 && this.isTTY) {
+    // Windows raw mode for non-stdin tty.ReadStream instances must go through
+    // uv_tty_set_mode, which needs a uv_tty_t wrapper for this fd. fd 0 uses
+    // Bun's shared stdin source and Source__setRawModeStdin instead, while
+    // non-TTY fds should keep the existing construction behavior and only fail
+    // if setRawMode() is later requested.
+    this.$bunNativePtr = new TTY(fd);
+  }
 }
 $toClass(ReadStream, "ReadStream", fs.ReadStream);
 
@@ -71,12 +80,17 @@ Object.defineProperty(ReadStream, "prototype", {
             return this;
           }
 
-          // If you call setRawMode before you call on('data'), the stream will
-          // not be constructed, leading to EBADF
-          // This corresponds to the `ensureConstructed` function in `native-readable.ts`
-          this.$start();
-
-          const err = handle.setRawMode(flag);
+          // If you call setRawMode before you call on('data'), native-readable
+          // streams need to be constructed before uv_tty_set_mode to avoid EBADF.
+          // This corresponds to the `ensureConstructed` function in
+          // `native-readable.ts`. Plain fd-backed tty.ReadStream instances, such
+          // as reopened CONIN$, do not have $start and only use the TTYWrap for
+          // console mode changes.
+          this.$start?.();
+
+          // Native-readable handles expose setRawMode(bool), but the TTYWrap
+          // binding mirrors libuv and expects numeric uv_tty_mode_t values.
+          const err = handle.setRawMode(handle instanceof TTY ? (flag ? 1 : 0) : flag);
           if (err) {
             this.emit("error", err);
             return this;

test/js/node/tty.test.ts

@@ -81,6 +81,77 @@ describe("ReadStream.prototype.setRawMode", () => {
       returnsThis: true,
     });
   });
+
+  test.skipIf(!isWindows)("supports raw mode on reopened CONIN$ streams", async () => {
+    let output = "";
+    const decoder = new TextDecoder();
+    const done = Promise.withResolvers<void>();
+    const eof = Promise.withResolvers<void>();
+
+    const proc = Bun.spawn({
+      cmd: [
+        bunExe(),
+        "-e",
+        `
+          const fs = require("node:fs");
+          const tty = require("node:tty");
+          let err;
+          const fd = fs.openSync("\\\\\\\\.\\\\CONIN$", "r+");
+          const input = new tty.ReadStream(fd);
+          input.on("error", e => (err = e.message));
+          const before = input.isRaw;
+          const ret = input.setRawMode(true);
+          const afterTrue = input.isRaw;
+          input.setRawMode(false);
+          const afterFalse = input.isRaw;
+          input.destroy();
+          process.stdout.write(
+            "RESULT " +
+              JSON.stringify({
+                isTTY: input.isTTY,
+                before,
+                afterTrue,
+                afterFalse,
+                returnsThis: ret === input,
+                ...(err ? { err } : {}),
+              }),
+          );
+          process.exit(0);
+        `,
+      ],
+      env: bunEnv,
+      terminal: {
+        cols: 200,
+        rows: 24,
+        data(_t, chunk: Uint8Array) {
+          output += decoder.decode(chunk, { stream: true });
+          if (output.includes("RESULT ") && output.includes("}")) done.resolve();
+        },
+        exit() {
+          eof.resolve();
+        },
+      },
+    });
+
+    await Promise.race([done.promise, eof.promise]);
+    proc.kill();
+    await proc.exited;
+    proc.terminal?.close();
+    output += decoder.decode();
+
+    const stripped = Bun.stripANSI(output).replace(/[\r\n]/g, "");
+    const match = stripped.match(/RESULT (\{[^}]*\})/);
+    if (!match) {
+      throw new Error("child did not emit RESULT; terminal output was: " + JSON.stringify(output));
+    }
+    expect(JSON.parse(match[1])).toEqual({
+      isTTY: true,
+      before: false,
+      afterTrue: true,
+      afterFalse: false,
+      returnsThis: true,
+    });
+  });
 });
 
 describe("WriteStream.prototype.getColorDepth", () => {