Re: Bug#867104: wanna-build issue with src:perl versioned Provides

[Sven Joachim <svenjoac@gmx.de>]

On 2017-07-06 12:02 +0300, Adrian Bunk wrote:

> On Thu, Jul 06, 2017 at 04:26:04AM +0200, Guillem Jover wrote:
>> On Wed, 2017-07-05 at 23:02:52 +0300, Adrian Bunk wrote:
>>...
>> > 6)
>> > 
>> > Package: a
>> > Depends: p (>= 1), p (<< 2)
>> > 
>> > Package: b
>> > Provides: p (=1)
>> > 
>> > Package: c
>> > Provides: p (=2)
>> > 
>> > When a and b are installed, can c be installed without removing a?
>> 
>> Yes, because b is enough to satisfy the dependency. This is not a
>> Conflicts/Breaks field after all.
>>...
>
> But it is being used for that purpose in *many* packages.
>
> As an example, there are ~ 300 Python3 packages that have
> "python3 (<< 3.7), python3 (>= 3.5~)" dependencies autogenerated using:
>
> Depends: ${python3:Depends}
>
> If this is considered a bug, then what is required is that dh-python adds 
> ${python3:Breaks}, and then each of these packages has to be changed to:
>
> Depends: ${python3:Depends}
> Breaks: ${python3:Breaks}

This will only necessary when (or rather if) some contender for the
python3 package comes along that is co-installable with the real python3
package and has a legitimate reason to "Provides: python3".

Which is not totally inconceivable, but seems unlikely at the moment.

Cheers,
       Sven