[Aptitude-devel] Bug#959869: Bug#959869: aptitude: "aptitude why" should take Provides into account

[Vincent Lefevre]

On 2020-05-06 13:17:11 +0200, Julian Andres Klode wrote:
> On Wed, May 06, 2020 at 12:43:54PM +0200, Vincent Lefevre wrote:
> > zira% aptitude why x11proto-core-dev
> > i   tk8.5-dev Depends x11proto-core-dev
> > 
> > but I can remove the package without breaking the dependency:
> > 
> > zira% apt remove -s x11proto-core-dev
> > NOTE: This is only a simulation!
> >       apt needs root privileges for real execution.
> >       Keep also in mind that locking is deactivated,
> >       so don't depend on the relevance to the real current situation!
> > Reading package lists... Done
> > Building dependency tree       
> > Reading state information... Done
> > The following packages will be REMOVED:
> >   x11proto-core-dev
> > 0 upgraded, 0 newly installed, 1 to remove and 10 not upgraded.
> > Remv x11proto-core-dev [2020.1-1]
> > 
> > Here, x11proto-core-dev is a transitional dummy package to x11proto-dev,
> > and x11proto-dev has:
> 
> IMO: why does not answer the question if there are any blockers to removal,
> it tells you why something was installed, and gives you the shortest path,
> and hence the answer is correct.

But IMHO, not much useful.

> It also follows Recommends or Suggests, and you can still remove
> those packages.

Yes, and this is a good thing. That's precisely the reason why
I use "aptitude why ..." to know whether it would be safe to
remove a package.

BTW, at the same time, the spurious "tk8.5-dev Depends x11proto-core-dev"
can hide real Recommends or Suggests.

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)