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Fixed #26226 -- Made related managers honor the queryset used for prefetching their results.

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Thanks Loïc for the suggested improvements and Tim for the review.
This commit is contained in:
Simon Charette 2016-02-18 22:37:11 -05:00
parent 5d240b070d
commit c92123cc1d
6 changed files with 133 additions and 22 deletions
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23
django/db/models/query.py
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@ -23,6 +23,7 @@ from django.db.models.query_utils import (
)
from django.db.models.sql.constants import CURSOR
from django.utils import six, timezone
from django.utils.deprecation import RemovedInDjango20Warning
from django.utils.functional import partition
from django.utils.version import get_version
@ -1608,6 +1609,9 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
msg = 'to_attr={} conflicts with a field on the {} model.'
raise ValueError(msg.format(to_attr, model.__name__))
# Whether or not we're prefetching the last part of the lookup.
leaf = len(lookup.prefetch_through.split(LOOKUP_SEP)) - 1 == level
for obj in instances:
instance_attr_val = instance_attr(obj)
vals = rel_obj_cache.get(instance_attr_val, [])
@ -1621,8 +1625,23 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
setattr(obj, to_attr, vals)
obj._prefetched_objects_cache[cache_name] = vals
else:
# Cache in the QuerySet.all().
qs = getattr(obj, to_attr).all()
manager = getattr(obj, to_attr)
if leaf and lookup.queryset is not None:
try:
apply_rel_filter = manager._apply_rel_filters
except AttributeError:
warnings.warn(
"The `%s.%s` class must implement a `_apply_rel_filters()` "
"method that accepts a `QuerySet` as its single "
"argument and returns an appropriately filtered version "
"of it." % (manager.__class__.__module__, manager.__class__.__name__),
RemovedInDjango20Warning,
)
qs = manager.get_queryset()
else:
qs = apply_rel_filter(lookup.queryset)
else:
qs = manager.get_queryset()
qs._result_cache = vals
# We don't want the individual qs doing prefetch_related now,
# since we have merged this into the current work.