[Django] #32983: Prevent developers from defining a related_name on symmetrical ManyToManyFields
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Reporter: | Owner: nobody
partofthething |
Type: | Status: new
Cleanup/optimization |
Component: Database | Version: 4.0
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
In ManyToManyField, if the `symmetrical` argument is passed, or if it's a
self-referential ManyToMany relationship, the related field on the target
model is not created. However, if a developer passes in the `related_name`
not understanding this fact, they may be confused until they find the
information about symmetrical relationship. Thus, it is proposed to raise
an error when the user defines a ManyToManyField in this condition.
--
Ticket URL: <https://code.djangoproject.com/ticket/32983>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | partofthething
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
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
-------------------------------------+-------------------------------------
* owner: nobody => partofthething
* status: new => assigned
Comment:
I have a PR that implements this incoming.
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:1>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | partofthething
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* has_patch: 0 => 1
Comment:
https://github.com/django/django/pull/14730
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:2>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* needs_better_patch: 0 => 1
* stage: Unreviewed => Accepted
Comment:
OK, I guess we can do something here — it probably is a source of
confusion.
The same issue was raised in #18021 (but as an invalid bug report, rather
than suggesting improving the messaging).
Looking at the PR — I'm sceptical about just raising an error — this will
likely break code in the wild.
Can we investigate adding a system check here instead?
There are several similar checks for related fields already:
https://docs.djangoproject.com/en/3.2/ref/checks/#related-fields
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:3>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Carlton Gibson):
Same issue **also** came up in #12641
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:4>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Nick Touran):
Absolutely. A system check is a much better approach than my initial idea
of the error. I have changed the patch to use a system check.
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:5>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* needs_better_patch: 1 => 0
Comment:
Unchecking patch needs improvement as instructed on the page, (pending
reviewer acceptance of course).
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:6>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
| checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* stage: Accepted => Ready for checkin
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:7>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Cleanup/optimization | Status: assigned
Component: Database layer | Version: 4.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Ready for
| checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Carlton Gibson <carlton@…>):
In [changeset:"1fb21ab3770bdc07fc847e131fa252759befadd2" 1fb21ab3]:
{{{
#!CommitTicketReference repository=""
revision="1fb21ab3770bdc07fc847e131fa252759befadd2"
Refs #32983 -- Removed unneeded related_name from test model definitions.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:8>
Django
ManyToManyFields
-------------------------------------+-------------------------------------
Type: | Touran
Component: Database layer | Version: 4.0
(models, ORM) |
Keywords: | Triage Stage: Ready for
| checkin
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"5d4f21b16f002ed5202a68d6977346ccf53b0b0e" 5d4f21b1]:
{{{
#!CommitTicketReference repository=""
revision="5d4f21b16f002ed5202a68d6977346ccf53b0b0e"
Fixed #32983 -- Added system check for redundant related_name on
symmetrical M2M fields.
Since ManyToManyFields defined with `symmetrical=True` do not add a
related field to the target model, including a `related_name` argument
will never do what the coder likely expects. This makes including
a related_name with a symmetrical model raise a system check warning.
ticket-32983
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/32983#comment:9>