The section on manual testing, including how to use a local checkout of
Django, is moved from the contribution intro to the submitting patches
docs. This makes it easier for reviewers and authors to follow best
practices.
- Changed EmailMessage.message() to construct a "modern email API"
email.message.EmailMessage and added policy keyword arg.
- Added support for modern MIMEPart objects in EmailMessage.attach()
(and EmailMessage constructor, EmailMessage.attachments list).
- Updated SMTP EmailBackend to use modern email.policy.SMTP.
Deprecated:
- Attaching MIMEBase objects (replace with MIMEPart)
- BadHeaderError (modern email uses ValueError)
- SafeMIMEText, SafeMIMEMultipart (unnecessary for modern email)
- django.core.mail.forbid_multi_line_headers()
(undocumented, but exposed via `__all__` and in wide use)
- django.core.mail.message.sanitize_address()
(undocumented, but in wide use)
Removed without deprecation (all undocumented):
- EmailMessage.mixed_subtype
- EmailMultiAlternatives.alternative_subtype
- Support for setting (undocumented) EmailMessage.encoding property
to a legacy email.charset.Charset object
Related changes:
- Dropped tests for incorrect RFC 2047 encoding of non-ASCII email
address localparts. This is specifically prohibited by RFC 2047, and
not supported by any known MTA or email client. (Python still
mis-applies encoded-word to non-ASCII localparts, but it is a bug that
may be fixed in the future.)
- Added tests that try to discourage using Python's legacy email APIs
in future updates to django.core.mail.
EmailMessage is intended to support lazy strings in any header field
(via coercion to `str` in forbid_multi_line_headers() called from
SafeMIMEMessage/Text/Multipart.__setitem__).
Set flake8 max-doc-length to 79 to enforce smaller line length limit
on docstrings and comments (per coding-style docs).
Updated docs to clarify both requirements are enforced by flake8 and
to remove some leftover language from the pre-black era.
Manually reformatted some long docstrings and comments that would be
damaged by the to-be-applied autofixer script, in cases where editorial
judgment seemed necessary for style or wording changes.
When looking for cached values in ManyRelatedManager and
ForwardManyToOneDescriptor walk up the whole chain of ancestors
(as long as they are cached) to find the prefetched relation.
Reordered the keyword-only EmailMessage parameters in the documentation
to group similar options together and move rarely used options later.
Used keywords for *all* parameters in EmailMessage examples to improve
clarity.
In public mail APIs, changed less frequently used parameters from
keyword-or-positional to keyword-only, emitting a warning during the
required deprecation period.
Updated mail tests in preparation for migrating from Python's legacy
to modern email API. The updated tests will pass with either Python API,
and focus on desired outcomes (e.g., that a message with non-ASCII
content parses accurately at the receiving end) rather than specific
implementation details (e.g., where rfc2047 encoded-words are split).
In a few cases that are still implementation dependent, added comments
identifying behavior specific to the legacy email API and expected to
change under the modern one.
Added comments identifying tests that cover internal functions planned
for deprecation, and (where meaningful) added similar tests to verify
the equivalent behavior in non-deprecated features.
Removed obsolete tests left over from Python 2.
