bug#54210: 27.1; appt-add checks for bad data only at end

[Francesco Potortì]

>>>>>> On Tue, 01 Mar 2022 13:54:47 +0100, Francesco Potortì <pot@potorti.it> 
>>>>>> said:
>    Francesco> appt-add asks the user for three parameters:
>    Francesco> - time (a time string)
>    Francesco> - message (a string)
>    Francesco> - minutes (a number)
>
>    Francesco> if the time string is badly formatted (for example if it is "8" 
> rather
>    Francesco> than "8.00") appt-add barfs.  That's ok, but it barfs only 
> after all
>    Francesco> three parameters have been read.  It should barf immediately 
> after
>    Francesco> submitting the wrong parameter.
>
>    Francesco> Maybe I'll find the time to look at it and propose a patch, but 
> since
>    Francesco> I don't know, I prefer reporting it now.
>
>Aha, a learning opportunity (for me :-) )
>
>How about this (I canʼt find a `read-time-of-day', unless org has one hidden
>away somewhere):
>
>diff --git a/lisp/calendar/appt.el b/lisp/calendar/appt.el
>index ebdafb438e..6a3ea7c356 100644
>--- a/lisp/calendar/appt.el
>+++ b/lisp/calendar/appt.el
>@@ -510,10 +510,12 @@ appt-add
> Optional argument WARNTIME is an integer (or string) giving the number
> of minutes before the appointment at which to start warning.
> The default is `appt-message-warning-time'."
>-  (interactive "sTime (hh:mm[am/pm]): \nsMessage: \n\
>-sMinutes before the appointment to start warning: ")
>-  (unless (string-match appt-time-regexp time)
>-    (user-error "Unacceptable time-string"))
>+  (interactive (list (let ((time (read-string "Time (hh:mm[am/pm]): ")))
>+                       (unless (string-match appt-time-regexp time)
>+                         (user-error "Unacceptable time-string"))
>+                       time)
>+                     (read-string "Message: ")
>+                     (read-string "Minutes before the appointment to start 
>warning: ")))
>   (and (stringp warntime)
>        (setq warntime (unless (string-equal warntime "")
>                         (string-to-number warntime))))
>

It works for me!