Jerry Zhang [off-list ref] writes:

Certain invocations of "git apply --3way"
will print error messages even though git
is able to fall back on apply_fragments and
apply the patch successfully with a return
value of 0. To fix, return early from
try_threeway() in the following cases:

I suspect that this is a recent breakage after we swapped the order
of 3way fallback.  It used to be that we tried the straight
application first (while suppressing the error messages) and then
fell back on 3way (while fully exposing the error messages).

It is understandable if we just swapped the order without changing
when errors are squelched, we may leak unnecessary error messages
while trying 3way and failing.

After having written all of the above, I just realized that the
swapping of the order was _your_ topic and you didn't have to be
explained any of the above ;-)  Just consider it as my thinking
aloud for the benefit of those who are reading from the sideline
(i.e. those not on the To/Cc list but are reading because this
message is sent to git@ mailing list).