cabal configure should fail if cannot satisfy setup-depends

[phadej]

Related: ulidtko/cabal-doctest#11

$ /opt/cabal/2.0/bin/cabal configure -w /opt/ghc/8.2.1/bin/ghc
Resolving dependencies...
Warning: solver failed to find a solution:
Could not resolve dependencies:
trying: distributive-0.5.2:+tagged
unknown package: tagged (dependency of distributive-0.5.2:+tagged)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: distributive, distributive-0.5.2:flag,
taggedTrying configure anyway.
[1 of 1] Compiling Main             ( dist/setup/setup.hs, dist/setup/Main.o )

... compiler error

That's very frustrating, and doesn't make sense.

I hope this can be fixed quickly, I'm more than happy to make a PR, if no-one objects (for a very good reason).

[23Skidoo]

I actually fixed this before, but it broke the containers test suite and was reverted. See #1575.

[phadej]

I'd say that default behavior should be: fail; if you don't it to fail, you have to say that explicitly.

[23Skidoo]

OK, this suggestion can be implemented, though people relying on that feature will be angry :-).

[angerman]

Not sure if this is related, but running cabal configure or cabal new-configure, with or without --allow-newer, where cabal is built with new-build, never returns but runs at 100% cpu.

-v gives:

[...]
Reading available packages of hackage.haskell.org...
Using most recent state specified from most recent cabal update

and then nothing.

[grayjay]

There is also #2614.

[phadej]

So many duplicate issues; should we close them (newers) with duplicate label?

[23Skidoo]

I guess we can close this in favour of #2614.