Re: [PATCH v4 2/8] Prioritize isar-apt repo over all others

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2018-02-12 11:08, Alexander Smirnov wrote:
> On 02/12/2018 12:41 PM, Jan Kiszka wrote:
>> On 2018-02-12 10:33, Alexander Smirnov wrote:
>>> On 02/11/2018 06:25 PM, Jan Kiszka wrote:
>>>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>>>
>>>> This ensures that we can override packages from upstream Debian or
>>>> other
>>>> external sources with our self-built versions. We achieve this for now
>>>> by asking multistrap to drop a preferences file for the buildchroot so
>>>> that dependency installations use the right priority. For the image
>>>> build, this does not work because all packages are pull during the
>>>> bootstrap. Therefore, we set aptdefaultrelease to isar to ensure that
>>>> our repo gets the higher priority.
>>>>
>>>
>>> I'm not sure that I completely understand this. What is the use-case for
>>> this? If you build your own copy of upstream package, this
>>> prioritization could be resolved by specifying suffix to version.
>>
>> Simple example: custom kernel build of linux-cip
>>
>> This generates a package called linux-image-amd64 (for amd64 as target),
>> and that may have a version < debian's kernel. Now, if we do not
>> prioritize isar-apt over upstream, the upstream kernel is taken, even
>> when you switched PREFERRED_PROVIDER (in fact, the build will break when
>> that virtual package linux-cip is selected but can't be installed due to
>> the version preference "newest").
> 
> Ok, but why you can't name you kernel 'linux-cip-image-amd64'? Having
> the same name as with original Debian one could be confusing.
> 

That is mandatory, in order to write packages that depend on THE kernel,
instead of "my-custom-kernel-in-version-4.4.112".

Jan