[Pymilter] pyspf SPF checking raises TypeError exception when checking erroneous record

[Stuart D Gathman]

On Mar 18, Kazuhiro Ogura transmitted in part:

> Can you try it with a zonedata like this?
>
> zonedata:
>  e3.example.com:
>  - SPF: v=spf1 a:mx1.example.com mx:mx1.example.com -all
>  mx1.example.com:
>  - CNAME: .

That does indeed break it with real DNS, but not as a test case.
The reason is that the mock DNSLookup doesn't include supplementary
data in addition to answers like a real DNS server does.  This
supplementary data gets added to a short lived (only for one mail
connection) cache, and having the empty CNAME in the cache is what
breaks it.

I am working on improving the mock DNSLookup.

Here is the fix:

@@ -1264,7 +1261,7 @@
          if name.endswith('.'): name = name[:-1]
          if not reduce(lambda x,y:x and 0 < len(y) < 64,
name.split('.'),True):
              return []   # invalid DNS name (too long or empty)
-        result = self.cache.get( (name, qtype) )
+        result = self.cache.get( (name, qtype), [])
          if result: return result
          cnamek = (name,'CNAME')
          cname = self.cache.get( cnamek )