authres.core.SyntaxError: Syntax error: Expected method

[niftylettuce]

Using `arcsign.py` in this package, I noticed that the following exception occurs:

```sh
ARC signature error message: Traceback (most recent call last):
 File "/var/www/production/source/node_modules/dkimpy/scripts/arcsign.py", line 79, in <module>
   main()
 File "/var/www/production/source/node_modules/dkimpy/scripts/arcsign.py", line 70, in main
   srv_id, cv, linesep=dkim.util.get_linesep(message))
 File "/home/deploy/.local/lib/python3.6/site-packages/dkim/__init__.py", line 1399, in arc_sign
   timestamp=timestamp, standardize=standardize)
 File "/home/deploy/.local/lib/python3.6/site-packages/dkim/__init__.py", line 1025, in sign
   for res in ar_headers]
 File "/home/deploy/.local/lib/python3.6/site-packages/dkim/__init__.py", line 1025, in <listcomp>
   for res in ar_headers]
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/__init__.py", line 206, in parse
   return authres.core.AuthenticationResultsHeader.parse(core_features(), string)
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/core.py", line 442, in parse
   return self.parse_value(feature_context, string)
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/core.py", line 454, in parse_value
   header._parse()
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/core.py", line 517, in _parse
   result = self._parse_resinfo()
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/core.py", line 550, in _parse_resinfo
   method, version, result = self._parse_methodspec()
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/core.py", line 570, in _parse_methodspec
   method, version = self._parse_method()
 File "/home/deploy/.local/lib/python3.6/site-packages/authres/core.py", line 583, in _parse_method
   raise SyntaxError('Expected method', self._parse_text)
```

[niftylettuce (niftylettuce)]

Maybe this should be filed on authres instead? Regardless, this affects this package too.

[Scott Kitterman (kitterman)]

Please provide the input used to cause this error so I can reproduce it.

[niftylettuce (niftylettuce)]

Here you go Scott, see attached file.

[niftylettuce (niftylettuce)]

I also noticed another issue where certain attachments sent caused `arcsign.py`'s `sys.stdout.write(message)` to be writing back the wrong message it was passed (e.g. the encoding was off, or something). But that's separate but I at least wanted to share, if I can manage to find time I will file that issue with reproducible attachment.

[Scott Kitterman (kitterman)]

And how did you call arcsign?

[niftylettuce (niftylettuce)]

The normal way, `cat message | args`

[niftylettuce (niftylettuce)]

I have a reproducible failing test case added to my repository via this commit as well: https://github.com/forwardemail/dkimpy/commit/4e541a80b8ea81d8d239bef8d5812cd6b154f3d9

[niftylettuce (niftylettuce)]

@kitterman - did you need anything else from me? I've been able to reproduce this 100% of the time from my local tests as mentioned with the message I attached in #3 <https://bugs.launchpad.net/dkimpy/+bug/1891417/comments/3>.

[Launchpad Janitor (janitor)]

[Expired for dkimpy because there has been no activity for 60 days.]