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

[Robert Yang]

On 6/25/19 10:14 PM, Richard Purdie wrote:
> 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.

Yes, make sense, I was also worried about. My first fix was in busybox.inc,
but looks a little tricky (Add a populate_packages_updatealternatives_append()
in busybox.inc) to make it work. Please see the V3.

// Robert

> 
> Cheers,
> 
> Richard
> 
> 
> 
>