#27744: Complex prefetch_related broken (from 1.9 to 1.10)
-------------------------------------+-------------------------------------
Reporter: Pascal | Owner: nobody
Briet |
Type: Bug | Status: new
Component: Database | Version: 1.10
layer (models, ORM) |
Severity: Normal | Keywords: prefetch
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
Was working on : 1.9.10
Is not working on : 1.10.5
{{{
#!div style="font-size: 80%"
{{{#!python
from offer.models import Price, PriceGrid
from django.db.models import Prefetch
price_queryset = Price.objects.prefetch_related('calculation_rules__rule')
pricegrids = PriceGrid.objects.all()
pricegrids = pricegrids.prefetch_related(Prefetch('prices',
queryset=price_queryset))
for pg in pricegrids: print(pg.pk)
}}}
}}}
`AttributeError: Cannot find 'rule' on RelatedManager object,
'prices__calculation_rules__rule' is an invalid parameter to
prefetch_related()`
But this still works :
{{{
#!div style="font-size: 80%"
{{{#!python
pgs =
PriceGrid.objects.prefetch_related('prices__calculation_rules__rule').all()
for pg in pgs:
for price in pg.prices.all():
for dr in price.calculation_rules.all():
print(dr.rule.pk)
}}}
}}}
Models (extracts) :
{{{
#!div style="font-size: 80%"
{{{#!python
class Price(models.Model):
grid = models.ForeignKey(PriceGrid,
related_name="prices")
class PriceCalculationRule(models.Model):
price = models.ForeignKey(Price, on_delete=models.CASCADE,
related_name="calculation_rules")
rule = models.ForeignKey(Rule, on_delete=models.PROTECT,
verbose_name="Condition")
}}}
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/27744>
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