[yocto] Change in override behavior?

[Paul Eggleton]

On Fri, 29 Apr 2016 08:06:16 Gary Thomas wrote:
> On 2016-04-29 07:08, Paul Eggleton wrote:
> > On Fri, 29 Apr 2016 06:24:55 Gary Thomas wrote:
> >> I used to be able to use something like this:
> >>     VARIABLE = "xyz"
> >> 
> >> and maybe in a .bbappend use
> >> 
> >>     VARIABLE_mymachine = "xyzzy"
> >> 
> >> where 'mymachine' is in OVERRIDES, which resulted in
> >> 
> >>     VARIABLE = "xyzzy"
> >> 
> >> This doesn't seem to work the same today, what I get is
> >> 
> >>     VARIABLE = "xyz"
> >>     VARIABLE_mymachine = "xyzzy"
> >> 
> >> Has this changed (recently)?  Why?  How to I make use of overrides?
> >> 
> >> Note: I'm using the latest Poky master (a9b503b26) updated 2016-04-28
> > 
> > When you say this is what you're seeing, how are you checking this?
> > bitbake -e ? Which part of that output are you looking at?
> > 
> > You *will* now see VARIABLE_mymachine in bitbake -e output even if
> > "mymachine" is in OVERRIDES - that's because the overridden values stay
> > in the datastore instead of a "finalisation" step eliminating them, in
> > order to allow OVERRIDES to be changed dynamically (possibly multiple
> > times) and still get the datastore contents you expect. That change was
> > made in the 2.0 release (jethro). However That should not affect the
> > final value of VARIABLE if "mymachine" is in OVERRIDES however. Are you
> > sure you are seeing what you think you're seeing? If so, is the bbappend
> > in fact being applied? Because if what you describe was really happening
> > then pretty much the entire system would be broken. I just checked a
> > similar case here and I see the expected results.
> 
> Yes, I am using 'bitbake -e <recipe> | grep ^VARIABLE' to look at this.
> 
> In my main recipe, I have this:
>    SOME_OTHER_VARIABLE ?= "${MACHINE}"
> and my .bbappend for that recipe has these lines:
>    SOME_OTHER_VARIABLE_my-target-A = "something-else1"
>    SOME_OTHER_VARIABLE_my-target-B = "something-else2"
> and local.conf has
>    MACHINE="my-target-B"
> 
> With Yocto 2.0 (Poky ceeb52a2544) I get this:
>    SOME_OTHER_VARIABLE = "something-else2"
>    SOME_OTHER_VARIABLE_my-target-A = "something-else1"
>    SOME_OTHER_VARIABLE_my-target-B = "something-else2"
> 
> With today's (Poky a9b503b26) I get this:
>    SOME_OTHER_VARIABLE = "my-target-B"
>    SOME_OTHER_VARIABLE_my-target-A = "something-else1"
>    SOME_OTHER_VARIABLE_my-target-B = "something-else2"
> 
> I also use this mechanism to set COMPATIBLE_MACHINE a lot and
> that doesn't seem to be working the same either.
> 
> Am I doing something incorrectly (and just got away with it for years)?
> 
> n.b. If you're interested, I can share the .bb/.bbappend files
> with you privately (I can't put them on the public list)

Ah, one thing... do your machine names have uppercase characters in them (as 
your pseudo-examples above do)? If so that was a 2.1 change; anything that is 
to be used as an override must now be lower case (so DISTRO, MACHINE, etc.)

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre