[Django] #36894: Email fail_silently, auth_user, auth_password are ignored when connection param provided

[Django]

#36894: Email fail_silently, auth_user, auth_password are ignored when connection
param provided
------------------------------+---------------------------------------
Reporter: Mike Edmunds | Type: Bug
Status: new | Component: Core (Mail)
Version: 6.0 | Severity: Normal
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
------------------------------+---------------------------------------
Most django.core.mail APIs take a `fail_silently` parameter which is
intended to suppress errors during sending, as well as a `connection`
parameter to provide a specific EmailBackend instance for sending. When
`connection` is specified, `fail_silently` is ignored.

To reproduce, configure your email settings to cause an error (e.g.,
`EMAIL_HOST="not.a.real.host"`) and:
{{{#!python
from django.core.mail import get_connection, send_mail

send_mail("subject", "body", None, ["t...@example.com"])
# Correct behavior: raises socket.gaierror: [Errno 8] nodename nor
servname provided, or not known

send_mail("subject", "body", None, ["t...@example.com"], fail_silently=True)
# Correct behavior: returns 0 messages sent, doesn't raise an error

send_mail("subject", "body", None, ["t...@example.com"], fail_silently=True,
connection=get_connection())
# Bug: despite fail_silently=True, raises socket.gaierror
}}}

A similar problem exists with the `auth_user` and `auth_password` params
to `send_mail()` and `send_mass_mail()`, which are also silently ignored
when a `connection` is provided.

There is no safe way to set any of these options on a connection
(EmailBackend instance) once it has been constructed. The correct way to
achieve the desired behavior is move `fail_silently` and the other params
into `get_connection()`:

{{{#!python
send_mail("subject", "body", None, ["t...@example.com"],
connection=get_connection(fail_silently=True, username="auth_user",
password="auth_password"))
}}}


**Suggested fix**

Django's email APIs should handle `fail_silently`, `auth_user` and
`auth_password` params as an error when `connection` is also provided.
This will involve:
- Changing the default from `fail_silently=False` to `fail_silently=None`
to be able to distinguish the cases. (Don't forget EmailMessage.send().)
- Raising a TypeError when `connection is not None and fail_silently is
not None`. Something like "fail_silently cannot be used with a connection.
(Pass fail_silently to get_connection() instead.)"
- Converting fail_silently==None to False where the high level APIs call
get_connection()
- Issuing similar error messages for `auth_user` and `auth_password`
(which already default to None)
- Updating tests to cover the new behavior
--
Ticket URL: <https://code.djangoproject.com/ticket/36894>
Django <https://code.djangoproject.com/>
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[Django]

#36894: Email fail_silently, auth_user, auth_password are ignored when connection
param provided

------------------------------+----------------------------------------
Reporter: Mike Edmunds | Owner: Kundan Yadav
Type: Bug | Status: assigned

Component: Core (Mail) | Version: 6.0

Severity: Normal | Resolution:

Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

------------------------------+----------------------------------------
Changes (by Kundan Yadav):

* owner: (none) => Kundan Yadav
* status: new => assigned

--
Ticket URL: <https://code.djangoproject.com/ticket/36894#comment:1>

[Django]

#36894: Email fail_silently, auth_user, auth_password are ignored when connection
param provided

-------------------------------------+-------------------------------------

Reporter: Mike Edmunds | Owner: Kundan

Type: | Yadav
Cleanup/optimization | Status: assigned

Component: Core (Mail) | Version: 6.0
Severity: Normal | Resolution:

Keywords: email fail_silently | Triage Stage: Accepted

Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0

-------------------------------------+-------------------------------------
Changes (by Natalia Bidart):

* keywords: => email fail_silently
* stage: Unreviewed => Accepted
* type: Bug => Cleanup/optimization

Comment:

Thank you Mike for this ticket! I agree with your rationale, but
personally I see this as a cleanup rather than a bug. I believe the was a
lacking of being explicit in the docs that if a connection is given, the
other connection-related params are ignored.

I would also include in your "Suggested fix" list to improve the docs.
--
Ticket URL: <https://code.djangoproject.com/ticket/36894#comment:2>

[Django]

#36894: Email fail_silently, auth_user, auth_password are ignored when connection
param provided
-------------------------------------+-------------------------------------
Reporter: Mike Edmunds | Owner: Kundan
Type: | Yadav
Cleanup/optimization | Status: assigned
Component: Core (Mail) | Version: 6.0
Severity: Normal | Resolution:
Keywords: email fail_silently | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0

Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Mike Edmunds):

* easy: 0 => 1


Old description:

New description:

- Updating docs to note the changed behavior (params that had been
silently ignored with `connection` will now raise an error)

--
Comment:

(Edited "suggested fix" to include adding versionchanged notes in relevant
docs.)
--
Ticket URL: <https://code.djangoproject.com/ticket/36894#comment:3>