More useful/hinting error messages in git-checkout

Signed-off-by: Josef Weidendorfer <Josef.Weidendorfer@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-checkout.sh b/git-checkout.sh
index 76e7f55..463ed2e 100755 (executable)
--- a/git-checkout.sh
+++ b/git-checkout.sh
@@ -22,7 +22,7 @@ while [ "$#" != "0" ]; do
                [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
                        die "git checkout: branch $newbranch already exists"
                git-check-ref-format "heads/$newbranch" ||
-                       die "we do not like '$newbranch' as a branch name."
+                       die "git checkout: we do not like '$newbranch' as a branch name."
                ;;
        "-f")
                force=1
@@ -75,9 +75,15 @@ done
 
 if test "$#" -ge 1
 then
+       hint=
+       if test "$#" -eq 1
+       then
+               hint="
+Did you intend to checkout '$@' which can not be resolved as commit?"
+       fi
        if test '' != "$newbranch$force$merge"
        then
-               die "updating paths and switching branches or forcing are incompatible."
+               die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
        fi
        if test '' != "$new"
        then
@@ -117,7 +123,8 @@ fi
 
 [ -z "$branch$newbranch" ] &&
        [ "$new" != "$old" ] &&
-       die "git checkout: you need to specify a new branch name"
+       die "git checkout: to checkout the requested commit you need to specify 
+              a name for a new branch which is created and switched to"
 
 if [ "$force" ]
 then