duplicate memory allocation in buildin-add.c

http://www.kernel.org/git/?p=git/git.git;a=commitdiff;h=0d78153952e70c21e94dc6b7eefcb2ac5337a902

buildin-add.c:

+static void fill_directory(struct dir_struct *dir, const char **pathspec)
+{
+ 	const char *path, *base;
+ 	int baselen;
...
+ 	if (baselen) {
+ 		char *common = xmalloc(baselen + 1);
+ 		common = xmalloc(baselen + 1);
+ 		memcpy(common, *pathspec, baselen);
+ 		common[baselen] = 0;
+ 		path = base = common;
+ 	}
...

Allocate memory twice for "common" variable, is it indended? I'm very confused @_@