From 512ee0f52889eb7f624f309cdc61fab57ab73a7b Mon Sep 17 00:00:00 2001 From: Russell Keith-Magee Date: Sat, 6 Jun 2009 06:14:05 +0000 Subject: [PATCH] Fixed #10572 -- Corrected the operation of the defer() and only() clauses when used on inherited models. git-svn-id: http://code.djangoproject.com/svn/django/trunk@10926 bcc190cf-cafb-0310-a4f2-bffc1f526a37 --- django/db/models/query.py | 20 ++++++- django/db/models/sql/query.py | 10 +++- tests/modeltests/defer/models.py | 92 +++++++++++++++++++++++++++++++- 3 files changed, 118 insertions(+), 4 deletions(-) diff --git a/django/db/models/query.py b/django/db/models/query.py index 0d35b0ba16..0f34fb8a5a 100644 --- a/django/db/models/query.py +++ b/django/db/models/query.py @@ -190,7 +190,25 @@ class QuerySet(object): index_start = len(extra_select) aggregate_start = index_start + len(self.model._meta.fields) - load_fields = only_load.get(self.model) + load_fields = [] + # If only/defer clauses have been specified, + # build the list of fields that are to be loaded. + if only_load: + for field, model in self.model._meta.get_fields_with_model(): + if model is None: + model = self.model + if field == self.model._meta.pk: + # Record the index of the primary key when it is found + pk_idx = len(load_fields) + try: + if field.name in only_load[model]: + # Add a field that has been explicitly included + load_fields.append(field.name) + except KeyError: + # Model wasn't explicitly listed in the only_load table + # Therefore, we need to load all fields from this model + load_fields.append(field.name) + skip = None if load_fields and not fill_cache: # Some fields have been deferred, so we have to initialise diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py index d290d60e63..15b9fd6366 100644 --- a/django/db/models/sql/query.py +++ b/django/db/models/sql/query.py @@ -635,10 +635,10 @@ class BaseQuery(object): # models. workset = {} for model, values in seen.iteritems(): - for field, f_model in model._meta.get_fields_with_model(): + for field in model._meta.local_fields: if field in values: continue - add_to_dict(workset, f_model or model, field) + add_to_dict(workset, model, field) for model, values in must_include.iteritems(): # If we haven't included a model in workset, we don't add the # corresponding must_include fields for that model, since an @@ -657,6 +657,12 @@ class BaseQuery(object): # included any fields, we have to make sure it's mentioned # so that only the "must include" fields are pulled in. seen[model] = values + # Now ensure that every model in the inheritance chain is mentioned + # in the parent list. Again, it must be mentioned to ensure that + # only "must include" fields are pulled in. + for model in orig_opts.get_parent_list(): + if model not in seen: + seen[model] = set() for model, values in seen.iteritems(): callback(target, model, values) diff --git a/tests/modeltests/defer/models.py b/tests/modeltests/defer/models.py index ce65065d40..96eb427811 100644 --- a/tests/modeltests/defer/models.py +++ b/tests/modeltests/defer/models.py @@ -17,6 +17,12 @@ class Primary(models.Model): def __unicode__(self): return self.name +class Child(Primary): + pass + +class BigChild(Primary): + other = models.CharField(max_length=50) + def count_delayed_fields(obj, debug=False): """ Returns the number of delayed attributes on the given model instance. @@ -33,7 +39,7 @@ def count_delayed_fields(obj, debug=False): __test__ = {"API_TEST": """ To all outward appearances, instances with deferred fields look the same as -normal instances when we examine attribut values. Therefore we test for the +normal instances when we examine attribute values. Therefore we test for the number of deferred fields on returned instances (by poking at the internals), as a way to observe what is going on. @@ -98,5 +104,89 @@ Using defer() and only() with get() is also valid. >>> Primary.objects.all() [] +# Regression for #10572 - A subclass with no extra fields can defer fields from the base class +>>> _ = Child.objects.create(name="c1", value="foo", related=s1) + +# You can defer a field on a baseclass when the subclass has no fields +>>> obj = Child.objects.defer("value").get(name="c1") +>>> count_delayed_fields(obj) +1 +>>> obj.name +u"c1" +>>> obj.value +u"foo" +>>> obj.name = "c2" +>>> obj.save() + +# You can retrive a single column on a base class with no fields +>>> obj = Child.objects.only("name").get(name="c2") +>>> count_delayed_fields(obj) +3 +>>> obj.name +u"c2" +>>> obj.value +u"foo" +>>> obj.name = "cc" +>>> obj.save() + +>>> _ = BigChild.objects.create(name="b1", value="foo", related=s1, other="bar") + +# You can defer a field on a baseclass +>>> obj = BigChild.objects.defer("value").get(name="b1") +>>> count_delayed_fields(obj) +1 +>>> obj.name +u"b1" +>>> obj.value +u"foo" +>>> obj.other +u"bar" +>>> obj.name = "b2" +>>> obj.save() + +# You can defer a field on a subclass +>>> obj = BigChild.objects.defer("other").get(name="b2") +>>> count_delayed_fields(obj) +1 +>>> obj.name +u"b2" +>>> obj.value +u"foo" +>>> obj.other +u"bar" +>>> obj.name = "b3" +>>> obj.save() + +# You can retrieve a single field on a baseclass +>>> obj = BigChild.objects.only("name").get(name="b3") +>>> count_delayed_fields(obj) +4 +>>> obj.name +u"b3" +>>> obj.value +u"foo" +>>> obj.other +u"bar" +>>> obj.name = "b4" +>>> obj.save() + +# You can retrieve a single field on a baseclass +>>> obj = BigChild.objects.only("other").get(name="b4") +>>> count_delayed_fields(obj) +4 +>>> obj.name +u"b4" +>>> obj.value +u"foo" +>>> obj.other +u"bar" +>>> obj.name = "bb" +>>> obj.save() + +# Finally, we need to flush the app cache for the defer module. +# Using only/defer creates some artifical entries in the app cache +# that messes up later tests. Purge all entries, just to be sure. +>>> from django.db.models.loading import cache +>>> cache.app_models['defer'] = {} """}