copy command fails when building only some components

[snoyberg]

Actions:

1. Create a project with both a library and executable
2. cabal clean
3. cabal configure
4. cabal build lib:packagename
5. cabal copy

Expected: command succeeds, copying over the library only, and not the test suite

Actual: errors out since the executable does not exist, e.g.:

Installing library in
/home/vagrant/.cabal/lib/x86_64-linux-ghc-7.10.2/tmp-0.1.0.0-JdaAODhQa7p5WhxMngbYYt
Installing executable(s) in /home/vagrant/.cabal/bin
Setup.hs: dist/build/tmp-exe/tmp-exe: does not exist

This problem could be mitigated by allowing copy to take a list of components like build does.

[lukehoersten]

+1

[mgsloan]

Recently ran into this one... +1