Installing Realistic Progression Zero and Realism Overhaul does not pull in Real Solar System

[waerloga]

I attempted a fresh install with CKAN 1.12.0, Realistic Progression v0.35, Realism Overhaul v10.2.0.

I the first attempt I had selected just RP-0 and it was missing many recommended mods from Realism Overhaul. @NathanKell stated that CKAN does not pull in second order recommended mods, so I tried again by selecting both RO and RP-0.

It did not attempt to auto install Real Solar System (nor RemoteTech RSS, but that's a obsolete requirement for 1.0.4-based RO/RP-0), it got the other recommended mods however.

[mheguy]

The good news: CKAN does pull second order recommends (try installing RSS, and because RO is required you'll get recommendations for B9 Procedural Parts and deadly re-entry (among others).

The bad news is that RO doesn't pull in RSS properly because it depends on a virtual module, and the relationship resolver just doesn't accept that.

I created a test branch: https://github.com/KSP-CKAN/CKAN-meta/tree/RO-RSS-test for easy testing.

GUI:
If RO depends RSS then as you install RO, RSS will install as expected (you choose a texture pack). If RO recommends RSS then RO will present a blank recommends page when the install reaches that point (essentially it knows there's a recommendation but can't fulfill RSS' depends).

CLI:
In both depends and recommends the CLI will install RO + RSS as expected.

[Postremus]

The solution should be to ask the user before the Installation begins what provider he wants to use.

[Dazpoet]

I thought situations like these where solved by #1002 but that might just be first order? In my naivity I'll just throw out the question if one can make whatever magic happened in #1002 happen in more places in the installation process without blowing things up?

[HebaruSan]

The bad news is that RO doesn't pull in RSS properly because it depends on a virtual module, and the relationship resolver just doesn't accept that.

I believe this was solved in the second side fix of #2577. The original test case here is spoiled because RP-0 now depends on RSS (which is automatically added to the change set), but RealismOverhaul still just recommends it, and installing RO shows RSS as a recommendation: