Document that sending an email with no recipients fails silently

[ian@…]

If EmailMessage.recipients() is empty, EmailMessage.send() returns 0 instead of raising an exception, even if fail_silently is False.

[ian@…]

I've fixed this in ​https://github.com/Ian-Foote/django/tree/ticket_22161.

[Sasha Romijn]

But that's technically not an error condition. send() does exactly what you asked it to do: send a mail to all recipients you specified. Why should this throw an exception?

Also, people may have become dependent on the behaviour that send() can be called even though recipients is empty. Therefore, if we do change this, I think it warrants at least a mention in the release notes, as a backwards incompatible change, although it will probably not hit too many users. I checked briefly, but it seems the current behaviour is not explicitly documented.

[ian@…]

I'm happy to add some documentation for this, but I'm not sure where is appropriate.

[Claude Paroz]

Erik has a point in his comment:3. We should first ponder arguments for or against raising an exception when sending email with no recipients.

[Tim Graham]

I think we should document the behavior. The EmailMessage class and receipients argument is documented in docs/topics/email.txt.

[Daniele Procida]

I've marked this ticket as especially suitable for people following the ​Don't be afraid to commit tutorial at the DjangoCon US 2014 sprints.

If you're tackling this ticket, please don't hesitate to ask me for guidance if you'd like any, either at the sprints themselves, or here or on the Django IRC channels, where I can be found as EvilDMP.

[Tim Graham <timograham@…>]

In 0f0a5c07f9f0f4d18d4c048ed6d9554965f79d5b:

Fixed #22161 -- Documented send() with no recipients won't raise an exception.

[Tim Graham <timograham@…>]

In 414e3fc59dcb429d9d96a91348f7c0eb661d70fa:

[1.6.x] Fixed #22161 -- Documented send() with no recipients won't raise an exception.

Backport of 0f0a5c07f9 from master

[Tim Graham <timograham@…>]

In af28f3c17515a1de9abb668942e896d777b67cba:

[1.7.x] Fixed #22161 -- Documented send() with no recipients won't raise an exception.

Backport of 0f0a5c07f9 from master