Re: Package cl is deprecated

[Hongyi Zhao]

On Wed, Jul 28, 2021 at 10:21 PM Leo Butler <leo.butler@umanitoba.ca> wrote:
>
> Hongyi Zhao <hongyi.zhao@gmail.com> writes:
>
> > On Wed, Jul 28, 2021 at 9:58 PM Eli Zaretskii <eliz@gnu.org> wrote:
> >>
> >> > From: Hongyi Zhao <hongyi.zhao@gmail.com>
> >> > Date: Wed, 28 Jul 2021 21:41:03 +0800
> >> > Cc: Jean-Christophe Helary <lists@traduction-libre.org>,
> >> >  help-gnu-emacs <help-gnu-emacs@gnu.org>,
> >> >  Thibaut Verron <thibaut.verron@gmail.com>
> >> >
> >> > > (debug-on-message "Package cl is deprecated")
> >> >
> >> > I tried this method, but meet the following warning:
> >> >
> >> > Warning (initialization): An error occurred while loading
> >> > ‘/home/werner/.emacs.d/init.el’:
> >> >
> >> > Symbol's function definition is void: debug-on-message
> >>
> >> debug-on-message is a variable, not a function.
> >
> > Then, how to pinpoint the target message?
>
> Ahem. I should have written
>
> (setq debug-on-message "Package cl is deprecated")

With the above line at the top of my ~/.emacs.d/init.el, Emacs reports
the following:

Debugger entered--Lisp error: "Package cl is deprecated"
  message("%s" "Package cl is deprecated")
  #f(compiled-function (msg) #<bytecode -0xb147a2018986fae>)("Package
cl is deprecated")
  apply(#f(compiled-function (msg) #<bytecode -0xb147a2018986fae>)
"Package cl is deprecated")
  timer-event-handler([t 0 0 0 nil #f(compiled-function (msg)
#<bytecode -0xb147a2018986fae>) ("Package cl is deprecated") idle 0])

It seems to me that the source el file in question does not correspond
quite so intuitively to the above messages.

> Ref.
>
> (info "elisp")
> (Info-index "debug-on-message")
>
> > Where is my mistake?
>
> As Eli noted, emacs must be in *info* looking at the elisp manual. My
> mistake.

Thank you, the following does the trick:

`C-h i M-: (info "elisp") RET M-: (Info-index "debug-on-message") RET':

-- Variable: debug-on-message
     If you set ‘debug-on-message’ to a regular expression, Emacs will
     enter the debugger if it displays a matching message in the echo
     area.  For example, this can be useful when trying to find the
     cause of a particular message.

But how to evaluate the above command more concisely?

> Anyhow, debug-on-message will help you isolate the source of the
> problem. You may need to play with the regexp ("Package ..."), though.

Thank you for your suggestion.

Hongyi