Re: [PATCH 2/1] init/Kconfig: Split expert menu into a separate file, init/Kconfig.expert

[Josh Triplett <josh@joshtriplett.org>]

On Mon, May 11, 2015 at 11:32:28PM +0200, Paul Bolle wrote:
> On Mon, 2015-05-11 at 14:18 -0700, Josh Triplett wrote:
> > However, that would produce *two* entries under the "General setup"
> > menu: a yes/no entry "Configure standard kernel features (expert users)"
> > with no submenu, and a "Some separate menu prompt here" entry with a
> > submenu but no '[ ]' for a yes/no option.  Integrating the two (without
> > using menuconfig's implicit "add stuff to submenu until an option's
> > prompt doesn't depend on this symbol" magic) requires new a kconfig
> > mechanism.
> 
> The diff pasted at the end of this message, which I quickly cobbled
> together an applies on top of this 2/1, generates these two lines in
> menuconfig (for EXPERT = 'y')
>     [*] Configure standard kernel features (expert users)
>         Standard kernel features  --->                   
> 
> Is squashing those two lines worth a new kconfig mechanism?

In my opinion, yes.  If you use the implicit (and error-prone)
menuconfig submenuing, you get a single entry with the '[ ]' and the
submenu.  There are currently 272 instances of "menuconfig" in Kconfig
files.  I'd like to have a less error-prone mechanism for people to use,
with an explicit "endmenu" at the end, and I don't want to leave any
incentive for people to need the more error-prone version.

I would be tempted to just make "menuconfig" require an endmenu, and
convert all users, but that would almost certainly break many
third-party users of kconfig.  So instead, I'm currently extending
"menu" (which already expects "endmenu") to allow the syntax
"menu config SYMBOL", which acts like a combination of "config SYMBOL"
and a menu with "visible if SYMBOL".  Diffstat for the patch I'm testing
right now:

 scripts/kconfig/zconf.y | 18 ++++++++++++++++++
  1 file changed, 18 insertions(+)

That seems worthwhile to have a less error-prone menu mechanism.

(The actual patch would also need to updated zconf.tab.c_shipped.)

(Also, the diff you posted would be smaller if you left "config EXPERT"
at the top of init/Kconfig.expert; why the move?)

- Josh Triplett