[OE-core] setting EXTRA_IMAGE_FEATURES explicitly in .bb file can screw things up

[Robert P. J. Day]

On Mon, 9 Jul 2012, Andrei Gherzan wrote:

> On Sat, Jul 7, 2012 at 9:52 PM, Robert P. J. Day <rpjday at crashcourse.ca> wrote:
>
>         a while back, i whined about the inconsistent usage of
>       EXTRA_IMAGE_FEATURES, like this as a snippet:
>
>       meta/recipes-sato/images/core-image-sato-sdk.bb:EXTRA_IMAGE_FEATURES += "tools-debug tools-profile tools-testapps
>       debug-tweaks"
>       meta/recipes-rt/images/core-image-rt-sdk.bb:EXTRA_IMAGE_FEATURES += "tools-debug tools-profile tools-testapps
>       debug-tweaks"
>       meta/recipes-extended/images/core-image-lsb-sdk.bb:EXTRA_IMAGE_FEATURES = "tools-debug tools-profile tools-testapps
>       debug-tweaks"
>
>       notice the mixing of "+=" and "=", which seems messy.  then i ran
>       across this in core-image-lsb-sdk.bb:
>
>       IMAGE_FEATURES += "apps-console-core tools-sdk dev-pkgs ssh-server-openssh"
>       EXTRA_IMAGE_FEATURES = "tools-debug tools-profile tools-testapps debug-tweaks"
>
>         that *can't* be right, can it?  the explicit setting of
>       EXTRA_IMAGE_FEATURES in that recipe file will override any such
>       setting in one's local.conf file, won't it?  and that's how the
>       current manual *advises* how to add more features through your
>       local.conf.
>
>         i tested this target with a standard local.conf, and checked the
>       environment to see:
>
>       ... snip ...
>       IMAGE_FEATURES="apps-console-core debug-tweaks tools-sdk
>       tools-testapps dev-pkgs tools-profile tools-debug ssh-server-openssh"
>
>       which looks fine according to the .bb file.
>
>         but if i add the following to my local.conf file (as the manual
>       suggests i do to add another feature):
>
>       EXTRA_IMAGE_FEATURES = "nfs-server"
>
>       i see *no* difference in the environment.  hasn't the setting in the
>       .bb file overridden the one in my local.conf?
>
>         i *can* get nfs-server added to my list of features with
>       (predictably):
>
>       IMAGE_FEATURES += "nfs-server"
>
>       but that doesn't strike me as a proper solution and will certainly
>       come as an unpleasant surprise to someone eventually.  thoughts?
>
>
> I agree that there is a problem with this image. Anyway the best way
> to debug a scenario like this is to use bitbake -e and grep on the
> thing you are interested in. I tried to add a feature to local conf
> and, as i expected, EXTRA_IMAGE_FEATURES ended up overwritten by
> recipe. 
>
> So IMHO the EXTRA_IMAGE_FEATURES variable in the image should be
> merged in the IMAGE_FEATURES above. I don't see the meaning of it. 

  yup, that was precisely the point i was making.  so given the
potential for confusion, what should be the "best practise" here?
based on my sketchy understanding, it seems the proper approach would
be to let recipe files use IMAGE_FEATURES exclusively, while
specifically reserving EXTRA_IMAGE_FEATURES for the developer's
local.conf file, and avoid the current unpleasant mixing.

  thoughts?

rday

-- 

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

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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