Bug #109703 Shell not obeying IdentityAgent config in .ssh/config file

Description:
I am using mysql-shell from my work laptop to connect to databases over an ssh tunnel.  

My company has a custom SSH agent.  I have discovered with some effort that mysql shell does not obey an "IdentityAgent" directive to specify the unix socket for that agent in my .ssh/config file.  Specifically, mysql shell will prompt me for a "Passphrase:" for my ssh tunnel host, but if I ssh directly to that host I get no such prompt.

MySQL shell DOES obey if I specify the same socket path using an SSH_AUTH_SOCK environment variable with the same socket path that I'm using for the IdentityAgent config.  If this is set properly, I no longer get the "Passphrase:" prompt and my connection succeeds.  

How to repeat:
1. Have an SSH host you can use for tunneling in mysql shell.  It should use an ssh key with a passphrase attached.
2. Ensure the socket path to your ssh agent is in an `IdentityAgent` line in an appropriate place in your .ssh/config
3. Ensure SSH_AUTH_SOCK is unset in your environment (`unset SSH_AUTH_SOCK`)
4. Attempt to use the SSH host via `shell.connect({ssh:"ssh hostname",...`
5. Get a passphrase prompt

Suggested fix:
I know you are using libssh.  Possibly there is an updated version there or the bug can be passed upstream.

Hi,

I'm not sure if I should leave this as "unsupported" as that's the real status of this bug or "verified". The "upstream" - you can report that bug to libssh but afaik it already exist (could not find it now but I'm pretty sure I'v seen it). 

Thank you for the report

My take is this:  I am not using libssh, I am using mysqlsh and this is my issue.  For all I know you already may be planning an alternative to libssh.  I think it'd be much more appropriate if Oracle staff raised the issue with the libssh developers if you feel that's where the problem lies.