[OE-core] [PATCH][RFC] sstate: allow specifying indirect dependencies to exclude from sysroot

[André Draszik]

I realise that this is basically working around the fact that -native
recipes don't get any RDEPENDS treatment AFAICS, except that RDEPENDS ==
DEPENDS, which is what I want to avoid, at least in certain cases...

I guess if computing proper RDEPENDS for -native recipes was easy, it would
have been done already?


Cheers,
Andre'


On Wed, 2018-04-25 at 15:12 +0100, André Draszik wrote:
> From: André Draszik <andre.draszik at jci.com>
> 
> Currently, a dependency on any -native recipe will pull in
> all dependencies of that -native recipe in the recipe
> sysroot. This behaviour might not always be wanted, e.g.
> when that -native recipe depends on build-tools that are
> not relevant for the current recipe.
> 
> This change adds a SSTATE_EXCLUDEDEPS_SYSROOT variable,
> which will be evaluated for such recursive dependencies to
> be excluded. The idea is similar to
>    http://lists.openembedded.org/pipermail/openembedded-core/2018-January/
> 146324.html
> except that the list is not hard-coded anymore.
> 
> SSTATE_EXCLUDEDEPS_SYSROOT is evaluated as two regular
> expressions of recipe and dependency to ignore, e.g. in
> the above flex-native / bison-native use-case, one would
> specify
> 
>     SSTATE_EXCLUDEDEPS_SYSROOT = ".*->(flex|bison)-native"
> 
> in layer.conf.
> 
> The existing special handling of "-initial" as well as
> "base-passwd" and "shadow-sysroot" could also be
> streamlined:
> 
>     SSTATE_EXCLUDEDEPS_SYSROOT += "\
>         .*->.*-initial.* \
>         .*(base-passwd|shadow-sysroot)->.* \
>     "
> 
> Another anticipated user is meta-java, where certain newer
> JDKs can only be bootstrapped (built) using older JDKs,
> but it doesn't make much sense to copy all those older
> JDKs and their own build tools (ant, etc.) into the
> sysroot of recipes wanting to be built using the newer JDK
> (only), e.g.:
> 
>     SSTATE_EXCLUDEDEPS_SYSROOT += "\
>         openjdk-8-native->(ant-native|attr-native|coreutils-
> native|icedtea7-native|libxslt-native|make-native|openssl-native|zip-
> native|unzip-native) \
>     "
> 
> Signed-off-by: André Draszik <andre.draszik at jci.com>
> ---
>  meta/classes/sstate.bbclass | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
> index 68089421f5..62e784e497 100644
> --- a/meta/classes/sstate.bbclass
> +++ b/meta/classes/sstate.bbclass
> @@ -901,6 +901,7 @@ def setscene_depvalid(task, taskdependees, notneeded,
> d, log=None):
>      # task is included in taskdependees too
>      # Return - False - We need this dependency
>      #        - True - We can skip this dependency
> +    import re
>  
>      def logit(msg, log):
>          if log is not None:
> @@ -961,6 +962,18 @@ def setscene_depvalid(task, taskdependees, notneeded,
> d, log=None):
>              # Nothing need depend on libc-initial/gcc-cross-initial
>              if "-initial" in taskdependees[task][0]:
>                  continue
> +            # Allow excluding certain recursive dependencies. If a recipe
> needs it should add a
> +            # specific dependency itself, rather than relying on one of
> its dependees to pull
> +            # them in.
> +            # See also http://lists.openembedded.org/pipermail/openembedd
> ed-core/2018-January/146324.html
> +            not_needed = False
> +            for excl in (d.getVar('SSTATE_EXCLUDEDEPS_SYSROOT') or
> "").split():
> +                if re.match(excl.split('->', 1)[0],
> taskdependees[dep][0]):
> +                    if re.match(excl.split('->', 1)[1],
> taskdependees[task][0]):
> +                        not_needed = True
> +                        break
> +            if not_needed:
> +                continue
>              # For meta-extsdk-toolchain we want all sysroot dependencies
>              if taskdependees[dep][0] == 'meta-extsdk-toolchain':
>                  return False