Sublibraries not registered if no library

[mpilgrem]

If a package has a library and sublibraries, the sublibraries are installed and registered.

However, if a package has only sublibraries, the sublibraries are installed but not registered. That appears to me to be a bug.

    let hasLibrary =
          case packageLibraries package of
            NoLibraries -> False
            HasLibraries _ -> True
        packageHasComponentSet f = not $ Set.null $ f package
        hasInternalLibrary = packageHasComponentSet packageInternalLibraries
        hasExecutables = packageHasComponentSet packageExes
        shouldCopy =
             not isFinalBuild
          && (hasLibrary || hasInternalLibrary || hasExecutables)
    when shouldCopy $ withMVar eeInstallLock $ \() -> do
      announce "copy/register"
      eres <- try $ cabal KeepTHLoading ["copy"]
      case eres of
        Left err@CabalExitedUnsuccessfully{} ->
          throwM $ CabalCopyFailed
                     (packageBuildType package == C.Simple)
                     (displayException err)
        _ -> pure ()
      when hasLibrary  $ cabal KeepTHLoading ["register"] -- <<<< This seems to be the problem