osxfuse/fuse — pull request #3 by fhgwright (2014-12-31 23:43:41+00:00)
Title: Makes non-error debug message less confusing.

In the POSIX API, errno is only valid when an error actually occurs,
and zero is not a valid error code. Hence, strerror() maps 0
to "Unknown error". However, the FUSE messaging API has an always
present "error" field which is zero in the no-error case. The
debugging messages shouldn't report this as "Unknown error".

I'm not sure why the code is using "out.error" instead of the local variable "error", but I left that aspect alone. For the master branch, it will need to use "out->error".