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 @_@