Making use of set_rcvar.

[Garrett Cooper]

On Jan 9, 2012, at 5:35 AM, Hiroki Sato <hrs at FreeBSD.org> wrote:

> Doug Barton <dougb at FreeBSD.org> wrote
>  in <4F0A22D8.8090206 at FreeBSD.org>:
> 
> do> On 01/07/2012 15:12, Hiroki Sato wrote:
> do> >  I am always wondering if defining $rcvar as "${name}_enable" at the
> do> >  end of load_rc_config() when $rcvar is undefined is bad idea.
> do> >
> do> >  Is there any problem with removing rcvar=... in individual rc.d
> do> >  scripts except for non-standard ones (empty or different from
> do> >  ${name}_enable)?  It looks simpler than writing the same line
> do> >  "rcvar=${name}_enable" many times in various places.
> do>
> do> This sounds like a great idea in theory, but in practice it doesn't work
> do> out, for 2 reasons. First, we have a lot of scripts in the base (about
> do> 1/3) that rely on the lack of any rcvar meaning that it gets run
> do> unconditionally. In order to provide backwards compatibility we'd have
> do> to add code to enable things by default that were previously unset.
> do> That's not hard to do, but ....
> do>
> do> The other reason is that for ports, the scripts generally look like this:
> do>
> do> load_rc_config foo
> do>
> do> : ${foo_enable:=NO}
> do>
> do> See the problem?
> 
> Removing rcvar=`set_rcvar`, and then adding rcvar="" into scripts
> that need to be run unconditionally would work.  However, I have no
> strong opinion about that.  I agree that it needs some more code
> anyway and keeping things simple is better.
> 
> Doug Barton <dougb at FreeBSD.org> wrote
>  in <4F0ABE04.5050503 at FreeBSD.org>:
> 
> do> > The use of "${name}_enable" does not add measurable overhead, but that
> do> > way more of an existing script might be used as a prototype unchanged.
> do>
> do> I understand what you're saying, and I know that the whole "use
> do> variables wherever we can" thing is all '1337 and computer science'y,
> do> but it's silly. The concept of a universal template that can be copied
> do> and pasted for different services is a pipe dream. There are already
> do> many things that need to be changed in the new script, and not updating
> do> rcvar for a new script causes clear and obvious failure messages.
> 
> I prefer to use ${name}_enable because putting the same keyword in
> two places always leads to a stupid typo issue.

+1
Thanks,
-Garrett