tty: make _read throw ERR_TTY_WRITABLE_NOT_READABLE

This change avoid an 'read ENOTCONN' error introduced by libuv 1.20.0
when trying to read from a TTY WriteStream. Instead, we are throwing
a more actionable ERR_TTY_WRITABLE_NOT_READABLE.

Fixes: #21203

PR-URL: #21654
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Shingo Inoue <[email protected]>
Reviewed-By: James M Snell <[email protected]>

doc/api/errors.md

@@ -1694,6 +1694,12 @@ A `Transform` stream finished with data still in the write buffer.
 
 The initialization of a TTY failed due to a system error.
 
+<a id="ERR_TTY_WRITABLE_NOT_READABLE"></a>
+### ERR_TTY_WRITABLE_NOT_READABLE
+
+This `Error` is thrown when a read is attempted on a TTY `WriteStream`,
+such as `process.stdout.on('data')`.
+
 <a id="ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET"></a>
 ### ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET
 

lib/internal/errors.js

@@ -828,6 +828,9 @@ E('ERR_TRANSFORM_ALREADY_TRANSFORMING',
 E('ERR_TRANSFORM_WITH_LENGTH_0',
   'Calling transform done when writableState.length != 0', Error);
 E('ERR_TTY_INIT_FAILED', 'TTY initialization failed', SystemError);
+E('ERR_TTY_WRITABLE_NOT_READABLE',
+  'The Writable side of a TTY is not Readable',
+  Error);
 E('ERR_UNCAUGHT_EXCEPTION_CAPTURE_ALREADY_SET',
   '`process.setupUncaughtExceptionCapture()` was called while a capture ' +
     'callback was already active',

lib/tty.js

@@ -25,7 +25,11 @@ const { inherits, _extend } = require('util');
 const net = require('net');
 const { TTY, isTTY } = process.binding('tty_wrap');
 const errors = require('internal/errors');
-const { ERR_INVALID_FD, ERR_TTY_INIT_FAILED } = errors.codes;
+const {
+  ERR_INVALID_FD,
+  ERR_TTY_INIT_FAILED,
+  ERR_TTY_WRITABLE_NOT_READABLE
+} = errors.codes;
 const { getColorDepth } = require('internal/tty');
 
 // Lazy loaded for startup performance.
@@ -122,6 +126,13 @@ WriteStream.prototype._refreshSize = function() {
   }
 };
 
+// A WriteStream is not readable from, so _read become a no-op.
+// this method could still be called because net.Socket()
+// is a duplex
+WriteStream.prototype._read = function() {
+  this.destroy(new ERR_TTY_WRITABLE_NOT_READABLE());
+};
+
 // Backwards-compat
 WriteStream.prototype.cursorTo = function(x, y) {
   if (readline === undefined) readline = require('readline');

test/pseudo-tty/test-tty-write-stream-resume-crash.js

@@ -0,0 +1,17 @@
+'use strict';
+
+const common = require('../common');
+const { WriteStream } = require('tty');
+const fd = common.getTTYfd();
+
+// Calling resume on a tty.WriteStream should be a no-op
+// Ref: https://github.com/nodejs/node/issues/21203
+
+const stream = new WriteStream(fd);
+stream.resume();
+
+stream.on('error', common.expectsError({
+  code: 'ERR_TTY_WRITABLE_NOT_READABLE',
+  type: Error,
+  message: 'The Writable side of a TTY is not Readable'
+}));