Problems with defcustom setter functions during byte-compile

Problems with defcustom setter functions during byte-compile

[David Engster]

I'd like to get some input on a problem I'm currently experiencing with
compiling CEDET upstream. Note that the following does not affect the
CEDET in Emacs trunk, since we do not generate the parsers there on the
fly.

The problem is a defcustom in srecode/map.el:

(defcustom srecode-map-load-path
   [... stuff snipped ...]
  :set 'srecode-map-load-path-set)

The :set function `srecode-map-load-path-set' is called as soon as this
file is loaded. This also happens when this file is byte-compiled.
However, this setter function will only work *after* CEDET was
successfully compiled since it depends on a parser which is generated
during build, so this is a typical chicken/egg problem.

While I can carefully rearrange the order of compilation so that this
still works, this is just destined to break regularly. Also, it slows
down compilation because the above is called pretty often.  Hence I
wonder if there's a "clean" way to avoid calling this setter function
during byte-compilation. Is there some kind of flag during
byte-compilation I could use? Or is there some clever 'eval-*' construct
which will fix this?

-David

Re: Problems with defcustom setter functions during byte-compile

[Stefan Monnier]

> (defcustom srecode-map-load-path
>    [... stuff snipped ...]
>   :set 'srecode-map-load-path-set)
> The :set function `srecode-map-load-path-set' is called as soon as this
> file is loaded.

Actually, when the defcustom is executed, the it's the initializer
that's called, and it just so happens that the default initializer in
turn calls the setter.
So you should be able to work around this problem by adding ":initialize
#'custom-initialize-default".


        Stefan

Re: Problems with defcustom setter functions during byte-compile

[David Engster]

Stefan Monnier writes:
>> (defcustom srecode-map-load-path
>>    [... stuff snipped ...]
>>   :set 'srecode-map-load-path-set)
>> The :set function `srecode-map-load-path-set' is called as soon as this
>> file is loaded.
>
> Actually, when the defcustom is executed, the it's the initializer
> that's called, and it just so happens that the default initializer in
> turn calls the setter.
> So you should be able to work around this problem by adding ":initialize
> #'custom-initialize-default".

Nifty. I didn't know that feature. And while it works as advertised, the
SRecode unit tests now fail. I guess that `srecode-map-load-path-set'
(which calls `srecode-map-update-map') really must be called when
srecode/map is loaded, it just shouldn't happen during byte-compilation...

Anyway, I guess that's more a fault on our side. At least for know I
"solved" this issue by simply setting `srecode-map-load-path' to nil
during byte-compilation.

-David