bug#31627: 27.0.50; isearch prompt not shown when `inhibit-message` is set to `t`

[Tino Calancha]

Christian Schwarzgruber <c.schwarzgruber.cs@gmail.com> writes:

> Hello Everybody!
>
> (setq inhibit-message t) hides isearch prompt. Is this defined behavior
> or a bug?
Its use is not intended to be set globally by users, because you don't
want to suppress all the calls to `message'; `message' is a common way
for Emacs to talk with its users, ask them for input or whatever.
Maybe something could be added in its docstring to make the point clear.

This var is mainly used by package developers in a controlled way:
typically by locally let-binding it around an expression.  For example,
imagine the package `foo' having an user option
`foo-verbose' to display/suppress not very important messages:

(defcustom foo-verbose t
  "If nil, suppress some messages"
  :type 'boolean
  :group 'foo)

(defun foo-set-vars ()
  (message "Setting package variables!")
  (setq foo-mint 100)
  (setq foo-star -1))

(defun foo-start ()
  (foo-procastinate-response)
  (message "Initialisation complete!"))
  
(defun foo-initialize ()
  (let ((inhibit-message (not verbose)))
    (foo-set-vars)
    (foo-start)))

That would be OK.
Another typical use is to suppress garbage messages
when writing tests.