wireprotov2peer: properly format errors
formatrichmessage() expects an iterable containing dicts with
well-defined keys. We were passing in something else. This caused
an exception.
Change the code to call formatrichmessage() with the proper argument.
And add a TODO to potentially emit the proper data structure from
the server in the first place.
Differential Revision: https://phab.mercurial-scm.org/D4441
Set up
$ hg init repo
$ cd repo
Try to import an empty patch
$ hg import --no-commit - <<EOF
> EOF
applying patch from stdin
abort: stdin: no diffs found
[255]
No dirstate backups are left behind
$ ls .hg/dirstate* | sort
.hg/dirstate