Merge pull request #1489 from mrkkrp/mrkkrp-message-on-missing-git-co…

…mmit

Show a message when resetting git commit fails

src/Stack/Config.hs

@@ -477,7 +477,8 @@ resolvePackageLocation menv projRoot (PLRemote url remotePackageType) = do
                     Nothing
                 readInNull dirTmp commandName menv
                     (resetCommand ++ [T.unpack commit])
-                    Nothing
+                    (Just $ "Please ensure that commit " <> commit <>
+                      " exists within " <> url)
 
         case remotePackageType of
             RPTHttpTarball -> do

src/System/Process/Read.hs

@@ -141,7 +141,7 @@ readProcessNull wd menv name args =
     sinkProcessStdout wd menv name args CL.sinkNull
 
 -- | Run the given command in the given directory. If it exits with anything
--- but success, prints an error and then calls 'exitWith' to exit the program.
+-- but success, print an error and then call 'exitWith' to exit the program.
 readInNull :: (MonadIO m, MonadLogger m, MonadBaseControl IO m, MonadCatch m)
            => Path Abs Dir -- ^ Directory to run in
            -> FilePath -- ^ Command to run