[OE-core] [PATCH v2 1/2] update-alternatives.bbclass: run update-alternatives firstly in postinst script

[Richard Purdie]

On Tue, 2019-06-25 at 20:44 +0800, Robert Yang wrote:
> Recipes like postfix run command newaliases in postinst, but newaliases is
> installed as newaliases.postfix, it needs run update-alternatives to update it
> to newaliases, so there was an error when installed postinst on target.
> 
> Fixed:
> $ opkg install postfix
> Configuring postfix.
> ///var/lib/opkg/info/postfix.postinst: line 4: newaliases: command not found
> 
> Run update-alternatives firstly will fix the problem. And handle busybox as an
> exception since it needs set basic tools such as sed command firstly, otherwise
> update-alternatives doesn't work.
> 
> Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
> ---
>  meta/classes/update-alternatives.bbclass | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/meta/classes/update-alternatives.bbclass b/meta/classes/update-alternatives.bbclass
> index b702e77..9ab9298 100644
> --- a/meta/classes/update-alternatives.bbclass
> +++ b/meta/classes/update-alternatives.bbclass
> @@ -265,6 +265,7 @@ python populate_packages_updatealternatives () {
>      if not update_alternatives_enabled(d):
>          return
>  
> +    bpn = d.getVar('BPN')
>      # Do actual update alternatives processing
>      for pkg in (d.getVar('PACKAGES') or "").split():
>          # Create post install/removal scripts
> @@ -284,8 +285,16 @@ python populate_packages_updatealternatives () {
>  
>              bb.note('adding update-alternatives calls to postinst/prerm for %s' % pkg)
>              bb.note('%s' % alt_setup_links)
> -            postinst = d.getVar('pkg_postinst_%s' % pkg) or '#!/bin/sh\n'
> -            postinst += alt_setup_links
> +            postinst = d.getVar('pkg_postinst_%s' % pkg)
> +            if postinst:
> +                # Busybox needs handle basic tools such as sed command
> +                # firstly, otherwise, update-alternatives doesn't work.
> +                if bpn == 'busybox':
> +                    postinst += alt_setup_links
> +                else:
> +                    postinst = alt_setup_links + postinst
> +            else:
> +                postinst = '#!/bin/sh\n' + alt_setup_links
>              d.setVar('pkg_postinst_%s' % pkg, postinst)
>  
>              bb.note('%s' % alt_remove_links)

We don't write classes like this. We could just keep piling special
cases one on top of the other and it becomes a horrible unmaintainable
mess. I therefore don't want to see recipes "special cased" like this
in core code and we need to find another, better way to handle this.

Cheers,

Richard