git-branch -D: make it work even when on a yet-to-be-born branch

diff --git a/git-checkout.sh b/git-checkout.sh
index a11c939c30f46561adb8179570d825a85fb8b57b..737abd0c094ae6cfb201fb46c28f4962a9826a02 100755 (executable)
--- a/git-checkout.sh
+++ b/git-checkout.sh
@@ -4,11 +4,14 @@ USAGE='[-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]'
 SUBDIRECTORY_OK=Sometimes
 . git-sh-setup
 
-old=$(git-rev-parse HEAD)
+old_name=HEAD
+old=$(git-rev-parse --verify $old_name 2>/dev/null)
 new=
+new_name=
 force=
 branch=
 newbranch=
+newbranch_log=
 merge=
 while [ "$#" != "0" ]; do
     arg="$1"
@@ -19,11 +22,14 @@ while [ "$#" != "0" ]; do
                shift
                [ -z "$newbranch" ] &&
                        die "git checkout: -b needs a branch name"
-               [ -e "$GIT_DIR/refs/heads/$newbranch" ] &&
+               git-show-ref --verify --quiet -- "refs/heads/$newbranch" &&
                        die "git checkout: branch $newbranch already exists"
                git-check-ref-format "heads/$newbranch" ||
                        die "git checkout: we do not like '$newbranch' as a branch name."
                ;;
+       "-l")
+               newbranch_log=1
+               ;;
        "-f")
                force=1
                ;;
@@ -44,25 +50,38 @@ while [ "$#" != "0" ]; do
                                exit 1
                        fi
                        new="$rev"
-                       if [ -f "$GIT_DIR/refs/heads/$arg" ]; then
+                       new_name="$arg^0"
+                       if git-show-ref --verify --quiet -- "refs/heads/$arg"
+                       then
                                branch="$arg"
                        fi
                elif rev=$(git-rev-parse --verify "$arg^{tree}" 2>/dev/null)
                then
                        # checking out selected paths from a tree-ish.
                        new="$rev"
+                       new_name="$arg^{tree}"
                        branch=
                else
                        new=
+                       new_name=
                        branch=
                        set x "$arg" "$@"
                        shift
                fi
+               case "$1" in
+               --)
+                       shift ;;
+               esac
                break
                ;;
     esac
 done
 
+case "$force$merge" in
+11)
+       die "git checkout: -f and -m are incompatible"
+esac
+
 # The behaviour of the command with and without explicit path
 # parameters is quite different.
 #
@@ -93,7 +112,11 @@ Did you intend to checkout '$@' which can not be resolved as commit?"
                git-ls-tree --full-name -r "$new" "$@" |
                git-update-index --index-info || exit $?
        fi
-       git-checkout-index -f -u -- "$@"
+
+       # Make sure the request is about existing paths.
+       git-ls-files --error-unmatch -- "$@" >/dev/null || exit
+       git-ls-files -- "$@" |
+       git-checkout-index -f -u --stdin
        exit $?
 else
        # Make sure we did not fall back on $arg^{tree} codepath
@@ -114,7 +137,7 @@ then
        cd "$cdup"
 fi
 
-[ -z "$new" ] && new=$old
+[ -z "$new" ] && new=$old && new_name="$old_name"
 
 # 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
@@ -126,10 +149,16 @@ fi
        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 [ "X$old" = X ]
+then
+       echo "warning: You do not appear to currently be on a branch." >&2
+       echo "warning: Forcing checkout of $new_name." >&2
+       force=1
+fi
+
 if [ "$force" ]
 then
-    git-read-tree --reset $new &&
-       git-checkout-index -q -f -u -a
+    git-read-tree --reset -u $new
 else
     git-update-index --refresh >/dev/null
     merge_error=$(git-read-tree -m -u $old $new 2>&1) || (
@@ -142,8 +171,7 @@ else
        # Match the index to the working tree, and do a three-way.
        git diff-files --name-only | git update-index --remove --stdin &&
        work=`git write-tree` &&
-       git read-tree --reset $new &&
-       git checkout-index -f -u -q -a &&
+       git read-tree --reset -u $new &&
        git read-tree -m -u --aggressive $old $new $work || exit
 
        if result=`git write-tree 2>/dev/null`
@@ -187,9 +215,11 @@ fi
 #
 if [ "$?" -eq 0 ]; then
        if [ "$newbranch" ]; then
-               leading=`expr "refs/heads/$newbranch" : '\(.*\)/'` &&
-               mkdir -p "$GIT_DIR/$leading" &&
-               echo $new >"$GIT_DIR/refs/heads/$newbranch" || exit
+               if [ "$newbranch_log" ]; then
+                       mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$newbranch")
+                       touch "$GIT_DIR/logs/refs/heads/$newbranch"
+               fi
+               git-update-ref -m "checkout: Created from $new_name" "refs/heads/$newbranch" $new || exit
                branch="$newbranch"
        fi
        [ "$branch" ] &&