EmailAlternative is not serializable

[Florent Messa]

Since 5.2, the type EmailAlternative has been introduced but it doesn't seem to be serializable due to its typename.

In [1]: from django.core.mail.message import EmailAlternative

In [2]: import pickle

In [3]: pickle.loads(pickle.dumps(EmailAlternative('test', 'test')))
---------------------------------------------------------------------------
PicklingError                             Traceback (most recent call last)
Cell In[3], line 1
----> 1 pickle.loads(pickle.dumps(EmailAlternative('test', 'test')))

PicklingError: Can't pickle <class 'django.core.mail.message.Alternative'>: attribute lookup Alternative on django.core.mail.message failed

I have already the patch, the typename should be updated for both EmailAlternative and EmailAttachment.

[Sarah Boyce]

Thank you! Refs #35537
Feel free to create a PR

[Sarah Boyce]

Not sure if you're still planning on creating a PR Florent, but just to note that we will probably pick this up next week if you haven't already.
As it's a release blocker, we need to resolve this soon 👍

[GitHub <noreply@…>]

In 0596263c:

Fixed #36309 -- Made email alternatives and attachments pickleable.

Regression in aba0e541caaa086f183197eaaca0ac20a730bbe4 and in
d5bebc1c26d4c0ec9eaa057aefc5b38649c0ba3b.

Thanks Florent Messa for the report, and Jake Howard and Claude
Paroz for the review.

[Natalia <124304+nessita@…>]

In 90fa9f4c:

[5.2.x] Fixed #36309 -- Made email alternatives and attachments pickleable.

Regression in aba0e541caaa086f183197eaaca0ac20a730bbe4 and in
d5bebc1c26d4c0ec9eaa057aefc5b38649c0ba3b.

Thanks Florent Messa for the report, and Jake Howard and Claude
Paroz for the review.

Backport of 0596263c3136bc26cffa670e5322bd0aa56c4d34 from main.