Well, if wd doesn't start with a /, then there will be no initial / to strip. Looking at the code, it seems like create() actually does strip initial /'s from wd, which was presumably the initial attempt to support chroot. But that didn't really work, since combine_path(wd, file) will still start with a slash if file does... Hence the stripping in other (but not all necessary) places, which rendered the stripping in create() unneccessary although nobody seems to have removed it. Quite a mess... :-/

In fact, stripping the intial / of wd seems like a very bad idea. Consider if the intended wd is "/foo".

combine_path("/foo", "../../bar") => "/bar", but combine_path("foo", "../../bar") => "../bar".

So if you strip the / from wd, you will be able to ascend above the chroot by using .., but that will not happen if you keep the / in wd and strip it from full instead.