Please describe the problem.

git annex upgrade to v6 configures a filter using git-annex smudge. With it, git diff can't be run on files external to the repository, without getting a lot of stderr output like:

fatal: '../test.txt' is outside repository
error: external filter 'git-annex smudge --clean %f' failed 1

This breaks vim-gitgutter signs, and possibly other tools as well.

What steps will reproduce the problem?

$ git init test
$ cd test
$ git annex init
$ git annex upgrade
$ git diff ../file1.txt ../file2.txt

What version of git-annex are you using? On what operating system?

6.20180913-1~bpo9+1 on Debian Stretch + backports.

fixed --Joey