apply --cached --whitespace=fix now failing on items added with "add -N"

I like to use git to remove trailing whitespace from my files. I use the following ~/.gitconfig to make this convenient:

[alias]
        wsadd = "!sh -c 'git diff -- \"$@\" | git apply --cached
--whitespace=fix;\
                git checkout -- ${1-.} \"$@\"' -"

The wsadd alias doesn't work with new files, so I have to use "git add -N" on them first. As of a week or two ago, the "apply --cached" step now fails with the following, assuming a new file named bar containing "foo " has been added with "add -N":

$ git diff -- "$@" | git apply --cached --whitespace=fix <stdin>:7: trailing whitespace. foo error: bar: already exists in index

The final "git checkout" at the end of wsadd truncates my file. I've changed the ";" to a "&&" to fix the truncation.

Were there any recent changes to "git apply" that might have caused this?

$ git --version git version 2.4.3.573.g4eafbef $ uname -a Linux <redacted> 3.13.0-53-generic #89-Ubuntu SMP Wed May 20 10:34:39 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux