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Fix prefetch_related behavior

fix_request_path_info
Markus Grimm 2018-06-28 15:08:36 +02:00
parent 63c33d595a
commit 6040e9891a
1 changed files with 34 additions and 33 deletions
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67
polymorphic/query.py
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@ -323,12 +323,12 @@ class PolymorphicQuerySet(QuerySet):
Finally we re-sort the resulting objects into the correct order and
return them as a list.
"""
ordered_id_list = [] # list of ids of result-objects in correct order
results = {} # polymorphic dict of result-objects, keyed with their id (no order)
resultlist = [] # polymorphic list of result-objects
# dict contains one entry per unique model type occurring in result,
# in the format idlist_per_model[modelclass]=[list-of-object-ids]
idlist_per_model = defaultdict(list)
indexlist_per_model = defaultdict(list)
# django's automatic ".pk" field does not always work correctly for
# custom fields in derived objects (unclear yet who to put the blame on).
@ -340,38 +340,32 @@ class PolymorphicQuerySet(QuerySet):
pk_name = self.model.polymorphic_primary_key_name
# - sort base_result_object ids into idlist_per_model lists, depending on their real class;
# - also record the correct result order in "ordered_id_list"
# - store objects that already have the correct class into "results"
base_result_objects_by_id = {}
content_type_manager = ContentType.objects.db_manager(self.db)
self_model_class_id = content_type_manager.get_for_model(self.model, for_concrete_model=False).pk
self_concrete_model_class_id = content_type_manager.get_for_model(self.model, for_concrete_model=True).pk
for base_object in base_result_objects:
ordered_id_list.append(base_object.pk)
for i, base_object in enumerate(base_result_objects):
# check if id of the result object occurres more than once - this can happen e.g. with base_objects.extra(tables=...)
if base_object.pk not in base_result_objects_by_id:
base_result_objects_by_id[base_object.pk] = base_object
if base_object.polymorphic_ctype_id == self_model_class_id:
# Real class is exactly the same as base class, go straight to results
results[base_object.pk] = base_object
if base_object.polymorphic_ctype_id == self_model_class_id:
# Real class is exactly the same as base class, go straight to results
resultlist.append(base_object)
else:
real_concrete_class = base_object.get_real_instance_class()
real_concrete_class_id = base_object.get_real_concrete_instance_class_id()
if real_concrete_class_id is None:
# Dealing with a stale content type
continue
elif real_concrete_class_id == self_concrete_model_class_id:
# Real and base classes share the same concrete ancestor,
# upcast it and put it in the results
resultlist.append(transmogrify(real_concrete_class, base_object))
else:
real_concrete_class = base_object.get_real_instance_class()
real_concrete_class_id = base_object.get_real_concrete_instance_class_id()
if real_concrete_class_id is None:
# Dealing with a stale content type
continue
elif real_concrete_class_id == self_concrete_model_class_id:
# Real and base classes share the same concrete ancestor,
# upcast it and put it in the results
results[base_object.pk] = transmogrify(real_concrete_class, base_object)
else:
real_concrete_class = content_type_manager.get_for_id(real_concrete_class_id).model_class()
idlist_per_model[real_concrete_class].append(getattr(base_object, pk_name))
real_concrete_class = content_type_manager.get_for_id(real_concrete_class_id).model_class()
idlist_per_model[real_concrete_class].append(getattr(base_object, pk_name))
indexlist_per_model[real_concrete_class].append((i, len(resultlist)))
resultlist.append(None)
# For each model in "idlist_per_model" request its objects (the real model)
# from the db and store them in results[].
@ -379,6 +373,7 @@ class PolymorphicQuerySet(QuerySet):
# Then we copy the extra() select fields from the base objects to the real objects.
# TODO: defer(), only(): support for these would be around here
for real_concrete_class, idlist in idlist_per_model.items():
indices = indexlist_per_model[real_concrete_class]
real_objects = real_concrete_class._base_objects.db_manager(self.db).filter(**{
('%s__in' % pk_name): idlist,
})
@ -411,8 +406,15 @@ class PolymorphicQuerySet(QuerySet):
deferred_loading_fields.append(translated_field_name)
real_objects.query.deferred_loading = (set(deferred_loading_fields), self.query.deferred_loading[1])
for real_object in real_objects:
o_pk = getattr(real_object, pk_name)
real_objects_dict = {
getattr(real_object, pk_name): real_object
for real_object in real_objects
}
for i, j in indices:
base_object = base_result_objects[i]
o_pk = getattr(base_object, pk_name)
real_object = copy.copy(real_objects_dict[o_pk])
real_class = real_object.get_real_instance_class()
# If the real class is a proxy, upcast it
@ -421,18 +423,17 @@ class PolymorphicQuerySet(QuerySet):
if self.query.annotations:
for anno_field_name in six.iterkeys(self.query.annotations):
attr = getattr(base_result_objects_by_id[o_pk], anno_field_name)
attr = getattr(base_object, anno_field_name)
setattr(real_object, anno_field_name, attr)
if self.query.extra_select:
for select_field_name in six.iterkeys(self.query.extra_select):
attr = getattr(base_result_objects_by_id[o_pk], select_field_name)
attr = getattr(base_object, select_field_name)
setattr(real_object, select_field_name, attr)
results[o_pk] = real_object
resultlist[j] = real_object
# re-create correct order and return result list
resultlist = [results[ordered_id] for ordered_id in ordered_id_list if ordered_id in results]
resultlist = [i for i in resultlist if i]
# set polymorphic_annotate_names in all objects (currently just used for debugging/printing)
if self.query.annotations: