Specifying shells for remote ob-shell sessions?

[David Dynerman]

Dear Org Mode Friends,

I’m having some trouble getting the shell I want to run on remote hosts in 
session ob-shell blocks - it seems that no matter what shell I specify, session 
blocks will always run /bin/sh. I’m not sure if this is an org or tramp 
configuration issue on my end, or a bug in org.

I’m pasting a snippet that reproduces the behavior in emacs -Q below. Does 
anyone have an inkling if this is a bug, or, alternatively, suggestions for how 
I can run remote ob-shell sessions with the shell of my choice?

Thank you,
David

#+BEGIN_SRC emacs-lisp                                                          
                                
  (require 'ob-shell)                                                           
                                
  (emacs-version)                                                               
                                
#+END_SRC                                                                       
                                

#+RESULTS:
: GNU Emacs 27.2 (build 1, x86_64-apple-darwin17.7.0, Carbon Version 158 AppKit 
1561.6)                         
:  of 2021-05-20                                                                
                                

#+BEGIN_SRC emacs-lisp                                                          
                                
  (org-version)                                                                 
                                
#+END_SRC                                                                       
                                

#+RESULTS:
: 9.4.4                                                                         
                                

#+BEGIN_SRC zsh :dir /ssh:remote-host:/home/ubuntu                              
                         
    echo $0
#+END_SRC                                                                       
                                

#+RESULTS:
: zsh                                                                           
                                

#+BEGIN_SRC zsh :dir /ssh:remote-host:/home/ubuntu :session foobar              
                         
echo $0
#+END_SRC                                                                       
                                

#+RESULTS:
|           |
| $ /bin/sh |