New subject: DNF: "There are following alternatives to this package"

13 Sep 2018


      On 09/13/2018 06:43 PM, Mathieu Bridon wrote:
...
On Thu, 2018-09-13 at 18:17 +0200, Tomas Orsava wrote:
...
We'd like to propose a new functionality for dnf: When a user tries
to install a package XYZ and dnf doesn't find it, dnf would recommend
them alternative packages. These offered packages would advertise
that they are an alternative for XYZ using a specially formatted
Provides tag.
For example, packages `python2-requests` and `python3-requests`
would both have the following tag:
  Provides: alternative-for(python-requests) = %{version}-

%{release}
(Possibly via the already existing and widespread %python_provide
macro in the Python case.)
And when the user would try to install `python-requests`, dnf would
look for packages with the relevant Provides tag and display them:
  # dnf install python-requests
    * There are following alternatives to this package:

python2-requests python3-requests
      No match for argument: python-requests
      Error: Unable to find a match
This would be very similar to an already existing functionality that
searches for lowercase package names:
  # dnf install python3-REQUESTS
    * Maybe you meant: python3-requests
  No match for argument: python3-REQUESTS
  Error: Unable to find a match


(That functionality is broken in some versions—RHBZ#1628514—so you
might not see this result at the moment.)
What are your thoughts?
It's neat, but it doesn't help catch typos, which seems like the most
probably case where I'd want such a feature.
How about instead of a scheme based on provides, just quickly check if
a package has a "similar" name?
Basically extend the existing check for lowercase you mention.
Catching typos would be useful, and I'd certainly support that addition, 
but this doesn't really scratch the itch I'm trying to solve.
We want to tell the user "these are exactly the alternatives available 
to you". Not guess, not rely on some typo resolution. We know what the 
alternatives are, here they are.
I've talked with people working on dnf and this looks like an easy 
mechanism to add, and it will be more reliable for the use cases it covers.
Tomas
...
$ git stats
   git: 'stats' is not a git command. See 'git --help'.
The most similar command is
           status

Re: DNF: "There are following alternatives to this package"