Re: [PATCH v2 06/15] update-alternatives: allow hooks before renaming files

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Tue, 2019-01-15 at 14:45 +0000, André Draszik wrote:
> From: André Draszik <andre.draszik@jci.com>
> 
> At the moment, the update alternatives handling is happening
> right after copying into PKGD during packaging time using
> an _append OVERRIDE to the copy function. This means that at
> this point the PACKAGES variable must have been fully
> populated, as that is a prerequisite for update-alternatives.
> 
> In other words, this makes it impossible to e.g. populate
> PACKAGES dynamically using do_split_packages() and still do
> update-alternatives, as do_split_packages() can never
> execute early enough in a deterministic way.
> 
> By converting the existing python function from a 'def'
> type function to a 'python' type function, we now make it
> possible for somebody to hook themselves between copying
> into PKGD and execution of update-alternatives, via
> a _prepend OVERRIDE, which is not possible with 'def' type
> functions.
> 
> [YOCTO #13058]

I don't think you need to do this. Can you add your function to the
start of PACKAGEBUILDPKGD rather than using
apply_update_alternative_renames_prepend
?
or maybe use PACKAGE_PREPROCESS_FUNCS?

In fact we should probably fix the update-alternatives class to use
PACKAGE_PREPROCESS_FUNCS rather than perform_packagecopy_append too.

Regardless, I'd like to see us try and make this more readable rather
than less which means separate functions and less prepend/appending and
more use of the variables...

Cheers,

Richard


> Signed-off-by: André Draszik <andre.draszik@jci.com>
> ---
>  meta/classes/update-alternatives.bbclass | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/meta/classes/update-alternatives.bbclass
> b/meta/classes/update-alternatives.bbclass
> index f1250f877b..ffedada2f6 100644
> --- a/meta/classes/update-alternatives.bbclass
> +++ b/meta/classes/update-alternatives.bbclass
> @@ -135,10 +135,10 @@ populate_packages[vardeps] += "${UPDALTVARS} 
> ${@gen_updatealternativesvars(d)}"
>  # place.
>  python perform_packagecopy_append () {
>      if update_alternatives_enabled(d):
> -        apply_update_alternative_renames(d)
> +        bb.build.exec_func('apply_update_alternative_renames', d)
>  }
>  
> -def apply_update_alternative_renames(d):
> +python apply_update_alternative_renames () {
>      # Check for deprecated usage...
>      pn = d.getVar('BPN')
>      if d.getVar('ALTERNATIVE_LINKS') != None:
> @@ -204,6 +204,7 @@ def apply_update_alternative_renames(d):
>                      os.unlink(src)
>                  else:
>                      bb.warn('%s: Unable to resolve dangling symlink:
> %s' % (pn, alt_target))
> +}
>  
>  PACKAGESPLITFUNCS_prepend = "populate_packages_updatealternatives "
>  
> -- 
> 2.20.1
>