> For the 5.29.* development cycle starting in May of this year, I would like 
> to be able to use a ranking of CPAN distros which goes beyond asking:
> 
> * "How many other distributions depend on this one?"
> 
> ... to asking:
> 
> * "How many distributions by other authors/maintainers depend on this one?"
> 
> Would that be feasible?  Has anyone attempted this already?

When we were discussing the River model at QAH, and in discussions afterwards, 
this came up. In the end we decided to keep things simple and go with the 
current common definition. There are some tools in the CPAN ecosystem that only 
count dependencies written by others.

We’d need to agree which dists get ignored in this alternate scheme. Consider 
this example:



Here MARY has released a bunch of dists, but Foo-Bar is also relied on by other 
dists written by MUNGO and MIDGE.

The river count for Foo-Bar would be 2 here (ignoring the whole branch that 
contains only dists from MARY), but the Foo river count should be 3, I think. 
Foo-Bar “counts”, because it in turn is depended on by dists from other 
authors. Otherwise the river count would be 2 for both Foo and Foo-Bar. 
Basically we’re starting at the “bottom" of the dependency graph, and trimming 
sub-graphs all from one author.

Also consider this example:



What’s the river count of Plant — 0, 1, or 3? I think it should be 1, in this 
alternate measure.

I.e. for sub-graphs by the same author, you only include the dist at the head 
of the sub-graph.

It would be useful to have both measures available: raw-river and author-river.

When looking at a dist there are (at least) three figures that might be of 
interest: the full river count (total number of direct and indirect 
dependencies), the author-filtered river count (as above), and the number of 
direct dependencies (which could be split in 2 as well).

Neil

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