[PATCH] Docs for git-checkout-script.

diff --git a/git-checkout-script b/git-checkout-script
index 5b49662e623a4f68f2796458daea3875911afb68..b31ded716d470a4975512ebc4cb912b3adb5fb7f 100755 (executable)
--- a/git-checkout-script
+++ b/git-checkout-script
@@ -1,18 +1,28 @@
 #!/bin/sh
-: ${GIT_DIR=.git}
+. git-sh-setup-script || die "Not a git archive"
+
 old=$(git-rev-parse HEAD)
 new=
 force=
 branch=
+newbranch=
 while [ "$#" != "0" ]; do
     arg="$1"
     shift
     case "$arg" in
+       "-b")
+               newbranch="$1"
+               shift
+               [ -z "$newbranch" ] &&
+                       die "git checkout: -b needs a branch name"
+               [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
+                       die "git checkout: branch $newbranch already exists"
+               ;;
        "-f")
                force=1
                ;;
        *)
-               rev=$(git-rev-parse "$arg")
+               rev=$(git-rev-parse --verify "$arg^0") || exit
                if [ -z "$rev" ]; then
                        echo "unknown flag $arg"
                        exit 1
@@ -22,19 +32,45 @@ while [ "$#" != "0" ]; do
                        exit 1
                fi
                new="$rev"
-               if [ -f "$GIT_DIR/revs/heads/$arg" ]; then
+               if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
                        branch="$arg"
                fi
                ;;
     esac
-    i=$(($i+1))
 done
 [ -z "$new" ] && new=$old
 
+#
+# If we don't have an old branch that we're switching to,
+# and we don't have a new branch name for the target we
+# are switching to, then we'd better just be checking out
+# what we already had
+#
+[ -z "$branch$newbranch" ] &&
+       [ "$new" != "$old" ] &&
+       die "git checkout: you need to specify a new branch name"
+
 if [ "$force" ]
 then
     git-read-tree --reset $new &&
        git-checkout-cache -q -f -u -a
 else
     git-read-tree -m -u $old $new
-fi && [ "$branch" ] && ln -sf "refs/heads/$branch" "$GIT_DIR/HEAD"
+fi
+
+# 
+# Switch the HEAD pointer to the new branch if it we
+# checked out a branch head, and remove any potential
+# old MERGE_HEAD's (subsequent commits will clearly not
+# be based on them, since we re-set the index)
+#
+if [ "$?" -eq 0 ]; then
+       if [ "$newbranch" ]; then
+               echo $new > "$GIT_DIR/refs/heads/$newbranch"
+               branch="$newbranch"
+       fi
+       [ "$branch" ] && ln -sf "refs/heads/$branch" "$GIT_DIR/HEAD"
+       rm -f "$GIT_DIR/MERGE_HEAD"
+else
+       exit 1
+fi