#36291: ManyToManyField empty when setting related_name and related_query_name
to
"+"
-------------------------------------+-------------------------------------
Reporter: iamhayder | Type: Bug
Status: new | Component: Database
| layer (models, ORM)
Version: 5.2 | 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
-------------------------------------+-------------------------------------
I’ve encountered an issue in my Django project where using the following
configuration in a ManyToManyField causes the field to return an empty
queryset—even though the underlying join table contains records. Notably,
this bug appears to be intermittent; sometimes the field behaves as
expected, while other times it consistently returns an empty queryset.
{{{
move_lines = models.ManyToManyField(
"accounting.AccountMoveLine",
verbose_name="Move Lines",
related_name="+",
related_query_name="+",
blank=True,
)
}}}
Steps to Reproduce:
Define a model with a ManyToManyField that includes related_name="+" and
related_query_name="+" (to disable reverse relations).
Create and save related records so that there are entries in the join
table.
Query the field using instance.move_lines.all().
Observe that the queryset is empty despite the related records existing.
Note that the bug does not occur consistently—there are occasions where
the field returns the expected records.
Expected Behavior:
The field should return all associated records when queried, regardless of
the reverse relation being disabled.
Actual Behavior:
When related_name and related_query_name are set to "+",
instance.move_lines.all() sometimes returns an empty queryset even though
related records exist. Removing these attributes (thus allowing Django to
generate default reverse names) consistently resolves the issue.
Additional Context:
This appears to be an issue where disabling the reverse relationship by
setting the related names to "+" intermittently interferes with the ORM’s
ability to construct the proper join, resulting in an empty result set on
the forward lookup. Has anyone else experienced this behavior, or is there
a known workaround or fix for this issue?
Thanks in advance for any help or insights!
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Ticket URL: <https://code.djangoproject.com/ticket/36291>
Django <https://code.djangoproject.com/>
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