Torsten Bögershausen [off-list ref] writes:
We only need to pay extra attention when there is an external
clean/smudge filter defined - otherwise we should be able to skip
it - after 10/10.
The last two words worries me. The goal of the suggested fix was to
make sure that
$ git reset --hard && git diff
reports that there _are_ differences in the working tree files, if
the to-git and to-working-tree conversion do not round-trip. It is
a total opposite of 10/10, which hides the fact that working tree
contents, if added to the index, would change the index.