By analyzing the blame information on this pull request, we identified @vcunat, @edolstra and @aszlig to be potential reviewers

cc @vcunat -- was there a purpose for the initial design?

Well, this depends on what the option is supposed to mean, as the user explicitly passed extraOutputsToInstall, too. I can't see a clear winner ATM.

Note that this is set by nixos config for the system env, and this PR may e.g. exclude some man pages in some configs (when modules put foo.out or foo.bin into systemPackages). It would seem better to me to include them in those cases, but maybe that should be expressed in some other way...

Hmm, indeed. Maybe this should be rather documented with some workaround... maybe toString would help. I'll test later.

removeAttrs gcc.cc.lib ["foo"] should certainly work in your case, but it utilizes knowledge about buildEnv implementation...

After more thinking, it does seem to me that not respecting extraOutputsToInstall when an output is chosen is more logical, because one can guess that without knowing our "outputs are recursively available in outputs" thing. That is, one might more likely expect that when he specifies foo.lib, foo.bin won't be used because it's not exposed at all.

However, I feel too biased to make any conclusions, and also completely skip the question of convenience (current way may make some patterns easier) and cost of changing vs benefits (it seems we don't use that corner case much, but I cannot testify). So I'm unsure how to proceed with this...

EDIT: ...and this might very fast roll down to a bikeshedding festival.

Let's just document this behavior for now, I think.

@abbradar so are you going to document this? Should this be merged? closed? I guess you can merge it youself…

I forgot about this completely D:

As I've said this is a controversial change without much benefit -- I'm personally for it but unless there is strong support I say let's just close it. I'll write documentation (and try not to forget this time :D) if workarounds listed in it would seem too awful we might return to this question ~_^