apt and package versioning

[Colin Watson]

On Thu, Mar 05, 2020 at 09:09:58PM +0000, Colin Law wrote:
> I am trying to understand an apt issue to with package versioning.
> The issue has arisen on Raspbian Buster, but I hope there will not be
> major objections to me asking about it here as the question is not
> specifically about Raspbian.  The issue is that if I check to see what
> version of npm is available for installation I see
> 
> $ apt policy npm
> npm:
>   Installed: (none)
>   Candidate: 5.8.0+ds6-4
>   Version table:
>      5.8.0+ds6-4 500
>         500 http://raspbian.raspberrypi.org/raspbian buster/main armhf Packages
> 
> 
> But if I try to install nodered I get
> 
> The following packages have unmet dependencies:
>  nodered : Depends: npm (>= 5.8)
> 
> I had assumed that apt would consider npm 5.8.0+ds6-4 to be >= 5.8, or
> am I misinterpreting what the problem is?

Your understanding of versioning is correct, so it's probably some other
problem.  Try "apt install nodered npm" and see what that tells you;
iterate adding package names from the error message until the resulting
error message makes sense. :-)

-- 
Colin Watson                                       [cjwatson at ubuntu.com]