rebase: consistently use branch_name variable

The variable "branch_name" holds the <branch> parameter in "git
rebase <upstream> <branch>", but one codepath did not use it after
assigning $1 to it (instead it kept using $1).  Make it use the
variable consistently.

Also, update an error message to say there is no such branch or
commit, as we are expecting either of them, and not limiting
ourselves to a branch name.

Signed-off-by: Kaartic Sivaraam <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
Signed-off-by: Kaartic Sivaraam <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: sivaraam

git-rebase.sh

@@ -518,7 +518,7 @@ case "$onto_name" in
 esac
 
 # If the branch to rebase is given, that is the branch we will rebase
-# $branch_name -- branch being rebased, or HEAD (already detached)
+# $branch_name -- branch/commit being rebased, or HEAD (already detached)
 # $orig_head -- commit object name of tip of the branch before rebasing
 # $head_name -- refs/heads/<that-branch> or "detached HEAD"
 switch_to=
@@ -528,15 +528,18 @@ case "$#" in
 	branch_name="$1"
 	switch_to="$1"
 
-	if git show-ref --verify --quiet -- "refs/heads/$1" &&
-	   orig_head=$(git rev-parse -q --verify "refs/heads/$1")
+	# Is it a local branch?
+	if git show-ref --verify --quiet -- "refs/heads/$branch_name" &&
+	   orig_head=$(git rev-parse -q --verify "refs/heads/$branch_name")
 	then
-		head_name="refs/heads/$1"
-	elif orig_head=$(git rev-parse -q --verify "$1")
+		head_name="refs/heads/$branch_name"
+	# If not is it a valid ref (branch or commit)?
+	elif orig_head=$(git rev-parse -q --verify "$branch_name")
 	then
 		head_name="detached HEAD"
+
 	else
-		die "$(eval_gettext "fatal: no such branch: \$branch_name")"
+		die "$(eval_gettext "fatal: no such branch/commit: \$branch_name")"
 	fi
 	;;
 0)
@@ -547,7 +550,7 @@ case "$#" in
 		branch_name=$(expr "z$branch_name" : 'zrefs/heads/\(.*\)')
 	else
 		head_name="detached HEAD"
-		branch_name=HEAD ;# detached
+		branch_name=HEAD
 	fi
 	orig_head=$(git rev-parse --verify HEAD) || exit
 	;;