Deprecate, then remove mode="total"

[szhorvat]

The "neighbour mode" mode parameter (igraph_neimode_t in C) can take values "out", "in", "all" and "total". However, "total" is just an alias for "all", and in my opinion in most contexts it is not a fitting name. The naming perhaps makes sense for degrees, but not for situation where it described in which direction to follow edges.

The same name has already been removed from the C core.

Can we start a deprecation process for R as well? Is there a clean deprecation route that is compatible with the auto-generation we are using, @maelle ?

@krlmlr At some point can you remove "total" from auto-generation and run revdepchecks, to see who is using it?

[szhorvat]

Many functions which are not auto-generated already do not use "total". Consistency is another reason to remove it. Perhaps we can keep it for degree and strength only, if revdepchecks indicate that people use it there.

[szhorvat]

This is very low priority. Given the workload we have, I would put this off indefinitely. I suggest not to spend time on it now @maelle.

[maelle]

Low priority, but it wouldn't be hard to put this into the lifecycle system, so please ping me again if you change your mind @szhorvat

[szhorvat]

Given how constrained we are for resources, I suggest dropping this task.

"total", as a descriptor, is a perfect fit for degree and strength, and not so good for all the rest. But some people may still be using it, so removing it is a breaking change.

Doing this would in the end be quite a bit of work for just an aesthetic improvements. I think we have higher priorities, such as exposing new functionality ...