• Version: 1.20.0+
• Platform: Mac OS X, Linux

In versions < 1.20.0, libuv did not repsect the user stdio flags for new pipe, which was fixed in 8f9ba2a.
In Node.js both tty.ReadStream and tty.WriteStream are in fact Duplexes, with in theory one side closed. Because this was not enforced, both could work as a duplex.
This behavior has existed for so long that it might be considered a breaking change.

I think the best way to approach this is to add flags to uv_tty_init to support flags, so that we can create one that is both readable and writable at the same time and restore the behavior in Node.js.