stack init --solver pulls down mingw

[ndmitchell]

If I do stack init --solver on a fresh machine in a directory with a cabal file it downloads Mingw, while a normal stack init doesn't. I think that's a bug. Stack 1.6 32bit on Windows.

[snoyberg]

Do you mean the msys2 distribution?

This doesn't seem unreasonable to me, --solver needs to run cabal-install, which requires GHC be available for checking the global database. In fact, it's only through some clever tricks (using global package hints) that stack init itself is able to bypass the need to install GHC. We only do that so that, in the common case, Stack doesn't need to install multiple different versions of GHC to test the latest nightly and LTS.

[ndmitchell]

I do mean msys2. Fair enough, that sounds reasonable. It was mostly problematic because #1212 means that installing GHC/msys2 is incredibly verbose, which was choking my CI engine, as the verbosity was coming from a new place, interspersed with essential messages I couldn't miss.