[OE-core] [PATCH] bitbake: do not set CCACHE_DISABLE=0

[Richard Purdie]

On Sun, 2012-07-22 at 11:39 +0200, Enrico Scholz wrote:
> Richard Purdie
> <richard.purdie-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r at public.gmane.org>
> writes:
> 
> >> ccache checks for existence of environment; not for its value:
> >> ...
> >> Hence, avoid setting of $CCACHE_DISABLE instead of assigning '0'.
> >
> > Why doesn't CCACHE_DISABLE[unexport] = "1" help here?
> 
> You mean, keeping the
> 
>  | export CCACHE_DISABLE ??= "${@[0,1][d.getVar('CCACHE', True) == '']}"
> 
> and requesting explicitly that user specifies
> 
>  | CCACHE_DISABLE[unexport] = "1"
> 
> in his .conf?  Sounds hacky and inconsistent and makes it impossible to
> set CCACHE_DISABLE by external environment.

The idea is that anyone enabling ccache would inherit the bbclass. The
above could therefore be simplified to a hard ??= 1 which the bbclass
resets and unexports.

> > Doesn't the unexport flag stop this entering the environment?
> 
> Perhaps.  In the current bitbake, 'unexport' takes precedence over
> 'export'.  But is this specified somewhere and will perhaps be changed
> in a later version.

I'll happily take a patch specifying that in the bitbake manual. Other
things would break too if this changed behaviour.

Cheers,

Richard