When attempting to base64-decode a payload of invalid length (1 mod 4),
properly recognize and handle it. The given data will be returned as-is,
i.e. not decoded, along with a new defect, InvalidBase64LengthDefect.
This is a wholesale reorganization and editing of the email documentation to
make the new API the standard one, and the old API the 'legacy' one. The
default is still the compat32 policy, for backward compatibility. We will
change that eventually.
This commit also restores the news item for 167256 that it looks like
Terry inadvertently deleted. (Either that, or I don't understand
now merging works...which is equally possible.)
Which also means that it is now producing *something* for any base64
payload, which is what leads to the couple of older test changes in
test_email. This is a slightly backward incompatible behavior change,
but the new behavior is so much more useful than the old (you can now
*reliably* detect errors, and any program that was detecting errors by
sniffing for a base64 return from get_payload(decode=True) and then doing
its own error-recovery decode will just get the error-recovery decode
right away). So this seems to me to be worth the small risk inherent
in this behavior change.
This patch also refactors the defect tests into a separate test file,
since they are no longer just parser tests.
This patch also deprecates the MalformedHeaderDefect. My best guess is that
this defect was rendered obsolete by a refactoring of the parser, and the
corresponding defect for the new parser (which this patch introduces) was
overlooked.
