Cannot make `compile-command` buffer local

Question

I've tried making compile-command buffer-local via

(defun compilation-make-locals (process)
  (set (make-local-variable 'compile-command)
       compile-command))
(add-hook 'compilation-start-hook 'compilation-make-locals)

but without success.

The variable compile-command is not updated the to latest value when I interactively set a new command when doing M-x compile.

Answer 1

(set (make-local-variable 'compile-command)
     compile-command))

The latter compile-command is evaluated after (make-local-variable 'compile-command) so this should be a no-op -- you're making the variable buffer-local, and then setting the buffer-local value to whatever the buffer-local value already was.

---

I'm unsure what you are wanting to happen here, though. What would "the latest value" be?

If it's the global value that you're wanting to copy to the buffer-local value, then you can obtain that with (default-value 'compile-command)

In the case where the buffer had a pre-existing buffer-local value, there may well be a difference between that and the global value.