Re: Wacky dependencies

[Gary Thomas <gary@mlbassoc.com>]

On 2012-11-16 07:24, Paul Eggleton wrote:
> On Friday 16 November 2012 07:12:38 Gary Thomas wrote:
>> I wanted to run an experiment with X11 vs GTK-directfb on my platform.
>> I built a complete image with X11 in DISTRO_FEATURES.
>> When I changed DISTRO_FEATURES to have gtk-directfb, nearly everything
>> was rebuilt!  Why on earth do GCC & EGLIBC have to be rebuilt??  This
>> doesn't seem logical at all to me.
>
> The build system is not able to determine whether a variable within a recipe
> depends on a single value within DISTRO_FEATURES, it only knows that it looks
> at the variable; thus any change to DISTRO_FEATURES will change the hash of
> all recipes that read DISTRO_FEATURES.
>
> I'd like to fix this but given that we check if DISTRO_FEATURES and other list
> variables like it contain values using inline python code i.e.
> ${@base_contains(...)} this seems like it would be tricky to implement in a
> reliable way.

In this particular case, I think the problem is that DISTRO_FEATURES contains
too many controls.  In particular, all of the LIBC settings which *are* important
to GCC & EGLIBC.  Maybe that part should be kept separate and only have DISTRO_FEATURES
contain non-compiler items?

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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