Emacs: suppress indent after && in shell-script-mode

Question

In shell-script-mode, when a line ends in &&, Emacs will indent the following line. Is there a way to switch that off? (I am concatenating most of my statements with &&. This gives finer control over error handling than set -e.)

Answer 1

The indentation code for shell scripts has been completely rewritten around the time of Emacs-24 to use SMIE, and SMIE itself has evolved during the life of Emacs-24, so the best solution may depend on your exact Emacs version, but with Emacs-24.5 you should be able to do:

• Go to the line with incorrect indentation.

• type M-x smie-config-show-indent which should show you the rules that were used to indent this line. It might say something like:

  Rules used: :before "&&" -> (column . 19), :before "[" -> nil, :elem basic -> 4, :after "&&" -> nil

Sadly the (column . 19) in there mostly implies that you won't be able to change this behavior in a "simple" way (i.e. you can't change it with smie-config-set-indent).

But I think the following should do it:

(defun my-sh-smie-sh-rules (origfun kind token)
  (pcase (cons kind token)
    (`(:before . "&&") nil)
    (_ (funcall origfun kind token))))
(advice-add 'sh-smie-sh-rules :around #'my-sh-smie-sh-rules)

You might like to M-x report-emacs-bug and request that such a config be made easier, since it's probably a fairly common indentation style.