expose a helper function peel_to_type().

diff --git a/git-checkout.sh b/git-checkout.sh
index f80939da5a15a006f2969cb966f4cdcc9dffdef9..bd74d701a1f0abb63e2bcdcb47035cb2c6eee745 100755 (executable)
--- a/git-checkout.sh
+++ b/git-checkout.sh
@@ -2,13 +2,13 @@
 
 OPTIONS_KEEPDASHDASH=t
 OPTIONS_SPEC="\
-git-branch [options] [<branch>] [<paths>...]
+git-checkout [options] [<branch>] [<paths>...]
 --
 b=          create a new branch started at <branch>
-l           create the new branchs reflog
-track       tells if the new branch should track the remote branch
+l           create the new branch's reflog
+track       arrange that the new branch tracks the remote branch
 f           proceed even if the index or working tree is not HEAD
-m           performa  three-way merge on local modifications if needed
+m           merge local modifications into the new branch
 q,quiet     be quiet
 "
 SUBDIRECTORY_OK=Sometimes
@@ -71,7 +71,8 @@ while test $# != 0; do
 done
 
 arg="$1"
-if rev=$(git rev-parse --verify "$arg^0" 2>/dev/null)
+rev=$(git rev-parse --verify "$arg" 2>/dev/null)
+if rev=$(git rev-parse --verify "$rev^0" 2>/dev/null)
 then
        [ -z "$rev" ] && die "unknown flag $arg"
        new_name="$arg"
@@ -82,11 +83,11 @@ then
        fi
        new="$rev"
        shift
-elif rev=$(git rev-parse --verify "$arg^{tree}" 2>/dev/null)
+elif rev=$(git rev-parse --verify "$rev^{tree}" 2>/dev/null)
 then
        # checking out selected paths from a tree-ish.
        new="$rev"
-       new_name="$arg^{tree}"
+       new_name="$rev^{tree}"
        shift
 fi
 [ "$1" = "--" ] && shift
@@ -266,7 +267,7 @@ if [ "$?" -eq 0 ]; then
        if test -n "$branch"
        then
                old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
-               GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from $old_branch_name to $branch" HEAD "refs/heads/$branch"
+               GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch"
                if test -n "$quiet"
                then
                        true    # nothing
@@ -278,7 +279,8 @@ if [ "$?" -eq 0 ]; then
                fi
        elif test -n "$detached"
        then
-               git update-ref --no-deref -m "checkout: moving to $arg" HEAD "$detached" ||
+               old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
+               git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $arg" HEAD "$detached" ||
                        die "Cannot detach HEAD"
                if test -n "$detach_warn"
                then