[OE-core] why use both IMAGE_FEATURES and EXTRA_IMAGE_FEATURES in a single .bb file?

[Robert P. J. Day]

On Thu, 29 Mar 2012, Martin Jansa wrote:

> On Thu, Mar 29, 2012 at 04:11:57AM -0400, Robert P. J. Day wrote:
> >
> >   given the recent excitement over "+=" and "=+", i thought i'd point
> > out again the occasional weirdness like this snippet from
> > core-image-sato-sdk.bb:
> >
> > IMAGE_FEATURES += "apps-console-core ${SATO_IMAGE_FEATURES} dev-pkgs tools-sdk qt4-pkgs"
> > EXTRA_IMAGE_FEATURES += "tools-debug tools-profile tools-testapps debug-tweaks"
>
> sometimes this is usefull to define "base" in IMAGE_FEATURES and then
> stuff which people tend to override in .bbappend put in EXTRA_IMAGE_FEATURES
>
> Maybe that's not the case here.. but separate variables are good even if
> it looks weird in .bb alone
>
> FOO = "blah"
> BAR = "base ${FOO}"
>
> allows to remove/replace "blah" very easy with .bbappend.

  ok, i can see that.  but that's the sort of thing that should be
explained somewhere in the basic OE documentation so users understand
what it means when they run across it.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

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