$(tty) returning wrong TTY

[TobiasDeBruijn]

Environment

Windows build number: Microsoft Windows [Version 10.0.18363.1082]
Your Distribution version: 18.04
Whether the issue is on WSL 2 and/or WSL 1: Linux version 4.4.0-18362-Microsoft ([email protected]) (gcc version 5.4.0 (GCC) ) #1049-Microsoft Thu Aug 14 12:01:00 PST 2020

Steps to reproduce

1. Create a ~/.bashrc file, containing export GPG_TTY = "$(tty)"
2. Close terminal
3. Open a new terminal, do nothing with it.
4. Open another new terminal, run e.g git commit -S to prompt te GPG password prompt

Expected behavior

GPG Password prompt opens on the terminal where git commit -S was run from

Actual behavior

GPG Password prompt opens on the terminal which was opened first

Possible explanation

I think the $(tty) in ~/.bashrc does not return the TTY of the terminal that was opened, but rather the terminal which was opened first, which would explain why the GPG password prompt opens on the wrong terminal.

Twitter thread with @MicrosoftHelpt

[Biswa96]

The $(tty) will results /dev/ttyX in WSL1 and /dev/pts/X in WSL2. It's by design. So, what does GPG_TTY expect?

[TobiasDeBruijn]

I think any TTY would work, regardless of where it is.

I'm getting /dev/ttyX on wsl.exe, or via the terminal app. So that seems to be all WSL1

[therealkenc]

It isn't related to WSL1 vs WSL2, but whatever is sending output to /dev/tty1, it is doing so by-design.

The Linux penguin icon in the screencap looks somewhat suspect. Might or might not be related. To the extent you are launching Ubuntu from the Start menu, it would normally have an Ubuntu icon.

Try the steps in the first screencap (with your WSL1 distro name of choice) and post the screencap. It is possible there was a behavioral change since 18363 but I don't have that build handy to check.

[TobiasDeBruijn]

That does seem to work. The screenshots:

Whilst echoing the TTY's, I also echoed GPG_TTY, which did not match the TTY of the terminal.

Could this be because ~/.bashrc is only ran on the first time a terminal opens?

And the Pinguin icon is there when you open wsl.exe from the start menu, or shift-rightclick > Open Linux Terminal in Explorer

[therealkenc]

shift-rightclick > Open Linux Terminal in Explorer

Okay.

Could this be because ~/.bashrc is only ran on the first time a terminal opens?

Improbable. If .bashrc was not run then GPG_TTY would not be set at all. The spaces around "=" in the OP are incorrect though, if they are to be taken literally. With shift-rightclicky....

Do the repro as suggested: Two powershell (or cmd) instances, wsl.exe from the prompt, like my previous post, with the two lines including the echo at the bottom of your .bashrc.

[TobiasDeBruijn]

I've added echo $GPG_TTY to ~/.bashrc. After doing this I closed the WSL window and launched it as you suggested via powershell. GPG_TTY was not echoed however.

After starting WSL a second time via PS, $(tty) and $GPG_TTY did not match:

The spaces around the '=' you pointed out were fixed before this 'test'

[therealkenc]

You have a tail -3 above (thanks!) but only two lines were returned. Which is at best unusual. There is likely something incorrect with your shell/login scripts, but I am unable to guess with the information provided. Your GPG_TTY is being set somewhere.

One big-hammer approach is to install a clean distribution of another name (say Ubuntu-20.04 from the store), put an echo hello at the top of .bashrc, and then move forward from there.

[TobiasDeBruijn]

Makes sense that it returned only 2 I think, since there were only 2 lines in the file :D