Output more information about installation error

[vyorkin]

For now, it just outputs:

spago: Installation failed.

I think it might be useful to output more contextual info about the installation error.

[f-f]

@vyorkin could you add more details about what you were trying to do? Also does rerunning the command fix it?

[vyorkin]

I was using my custom package set vyorkin-forks/spacchetti@88e5496#diff-3cd1c746ca940713759badf789478307R2203, the problem was that I had invalid repo url (doolse's repo is behind like 6 commits and has no v6.0.0 tag).

[f-f]

Cool, thanks 👍

Then I guess a good fix for this would be to print out the git commands output in case of error.

P.S.: are you basing multiple repos on your package set? Because if you have only one repo you can avoid maintaining a package set by depending on the upstream spacchetti and adding your overrides to the local packages.dhall

[vyorkin]

got it, thank you!
yeah, there are quite a few additional packages that I use pretty often vyorkin-forks/spacchetti@4f886cf, so I've just decided to maintain a custom package set (I'm still not sure about this decision though)

[f-f]

@vyorkin fix up in #59

Now the failure output looks something like this:

[..some more output above..]

Failed to install dependency "react-basic"

Git output:
fatal: Couldn't find remote ref f-f/nonexistent-branch

spago: Installation failed.