This PR replaces #1977. The reason for the replacement is two-fold.
The fix itself is different is that if the CTE header doesn't exist in the original message, it is inserted. This is important because the new CTE could be quoted-printable whereas the original is implicit 8bit.
Also the tests are different. The test_nonascii_as_string_without_cte test in #1977 doesn't actually test the issue in that it passes without the fix. The test_nonascii_as_string_without_content_type_and_cte test is improved here, and even though it doesn't fail without the fix, it is included for completeness.
Automerge-Triggered-By: @warsaw
This defaults to True in the compat32 policy for backward compatibility,
but to False for all new policies.
Patch by Milan Oberkirch, with a few tweaks.
This is more RFC compliant (see issue) and fixes a problem with
signature verifiers rejecting the part when signed. There is some
amount of backward compatibility concern here since it changes
the output, but the RFC issue coupled with fixing the problem
with signature verifiers seems worth the small risk of breaking
code that depends on the current incorrect output.
This is a bit of an ugly hack because of the way generator pieces together the
output message. The deepcopys aren't too expensive, though, because we know it
is only called on messages that are not multiparts, and the payload (the thing
that could be large) is an immutable object.
Test and preliminary work on patch by Vajrasky Kok.
Previously the parts of the message retained whatever linesep they had on
read, which means if the messages weren't read in univeral newline mode, the
line endings could well be inconsistent. In general sending it via smtplib
would result in them getting fixed, but it is better to generate them
correctly to begin with. Also, the new send_message method of smtplib does
not do the fixup, so that method is producing rfc-invalid output without this
fix.
Previously the parts of the message retained whatever linesep they had on
read, which means if the messages weren't read in univeral newline mode, the
line endings could well be inconsistent. In general sending it via smtplib
would result in them getting fixed, but it is better to generate them
correctly to begin with. Also, the new send_message method of smtplib does
not do the fixup, so that method is producing rfc-invalid output without this
fix.
When the new policies are used (and only when the new policies are explicitly
used) headers turn into objects that have attributes based on their parsed
values, and can be set using objects that encapsulate the values, as well as
set directly from unicode strings. The folding algorithm then takes care of
encoding unicode where needed, and folding according to the highest level
syntactic objects.
With this patch only date and time headers are parsed as anything other than
unstructured, but that is all the helper methods in the existing API handle.
I do plan to add more parsers, and complete the set specified in the RFC
before the package becomes stable.
This patch primarily does two things: (1) it adds some internal-interface
methods to Policy that allow for Policy to control the parsing and folding of
headers in such a way that we can construct a backward compatibility policy
that is 100% compatible with the 3.2 API, while allowing a new policy to
implement the email6 API. (2) it adds that backward compatibility policy and
refactors the test suite so that the only differences between the 3.2
test_email.py file and the 3.3 test_email.py file is some small changes in
test framework and the addition of tests for bugs fixed that apply to the 3.2
API.
There are some additional teaks, such as moving just the code needed for the
compatibility policy into _policybase, so that the library code can import
only _policybase. That way the new code that will be added for email6
will only get imported when a non-compatibility policy is imported.
