[commit: ghc] master: ghc-pkg: Print something when no packages are found; fixes #6119 (55478b1)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/55478b1ef856d47fba7e7dbd86baa88030d1b1cf

>---------------------------------------------------------------

commit 55478b1ef856d47fba7e7dbd86baa88030d1b1cf
Author: Ian Lynagh <[email protected]>
Date:   Thu Oct 11 21:31:00 2012 +0100

    ghc-pkg: Print something when no packages are found; fixes #6119
    
    We used to say
    
        $ ghc-pkg list blargle
        /usr/local/lib/ghc-7.4.1/package.conf.d
    
    which may imply that blargle was found in
    /usr/local/lib/ghc-7.4.1/package.conf.d

>---------------------------------------------------------------

 utils/ghc-pkg/Main.hs |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/utils/ghc-pkg/Main.hs b/utils/ghc-pkg/Main.hs
index d992b54..0f5bd15 100644
--- a/utils/ghc-pkg/Main.hs
+++ b/utils/ghc-pkg/Main.hs
@@ -985,7 +985,10 @@ listPackages verbosity my_flags mPackageName mModuleName = do
       broken = map sourcePackageId (brokenPackages pkg_map)
 
       show_normal PackageDB{ location = db_name, packages = pkg_confs } =
-          hPutStrLn stdout $ unlines ((db_name ++ ":") : map ("    " ++) pp_pkgs)
+          do hPutStrLn stdout (db_name ++ ":")
+             if null pp_pkgs
+                 then hPutStrLn stdout "    (no packages)"
+                 else hPutStrLn stdout $ unlines (map ("    " ++) pp_pkgs)
            where
                  pp_pkgs = map pp_pkg pkg_confs
                  pp_pkg p