SSH from WSL acts as if overwrite were enabled while actually inserting

Hello all,

Sorry about the confusing subject line, it’s the best I could think of to succinctly summarize the issue at hand. I’ve been running into an issue with FreeBSD from 10.x to 12-CURRENT and wanted to check with the mailing list before I bugged it to make sure it is a FreeBSD bug and not a WSL (the new Linux subsystem for Windows) bug.

When I ssh into a FreeBSD host from a TERM=xterm-256color host that has no problem SSHing into Linux machines, the following behavior is observed (regardless of the $TERM value under FreeBSD or the SSH shell I’m logging into).

Imagine the prompt currently reads as follows with the cursor at the space denoted by _ in the text below:

user_at_freebsd % foo_bar

If I type in ` foo` at this point, the prompt now reads

user_at_freebsd %  foo foo_

However, the _actual_ contents of the prompt are really

user_at_freebsd % foo foo bar_

i.e. the _displayed_ prompt acted as if OVERWRITE were on, but the actual behavior is that INSERT was enabled. The actual behavior is the expected behavior, which is what the prompt should have shown.

I do not experience this behavior when using, say, Putty instead of OpenSSH under WSL. I also do not experience this behavior when SSHing into a non-FreeBSD host.

If this is not a FreeBSD bug, I’ll raise it with the WSL team who have proven to be very earnest in their attempts at fixing all compatibility issues via their GitHub presence.

(A screenshot of the observed behavior, if it helps: http://i.imgur.com/k6hVtbQ.png )

Thank you,

Mahmoud Al-Qudsi
NeoSmart Technologies