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Fixed #12057 -- Corrected regression of caching performance when a mo…

…del contained a callable default. Thanks to Michael Thornhill for the excellent assistance tracking this problem.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11681 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit 96658ef2d24bd05c75aa98c5318d49f7e26549e7 1 parent c5c7791
@freakboy3742 freakboy3742 authored
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2  AUTHORS
@@ -422,7 +422,7 @@ answer newbie questions, and generally made Django that much better:
Travis Terry <tdterry7@gmail.com>
thebjorn <bp@datakortet.no>
Zach Thompson <zthompson47@gmail.com>
- Michael Thornhill
+ Michael Thornhill <michael.thornhill@gmail.com>
Deepak Thukral <deep.thukral@gmail.com>
tibimicu@gmx.net
tobias@neuyork.de
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12 django/db/models/base.py
@@ -293,7 +293,14 @@ def __init__(self, *args, **kwargs):
if rel_obj is None and field.null:
val = None
else:
- val = kwargs.pop(field.attname, field.get_default())
+ try:
+ val = kwargs.pop(field.attname)
+ except KeyError:
+ # This is done with an exception rather than the
+ # default argument on pop because we don't want
+ # get_default() to be evaluated, and then not used.
+ # Refs #12057.
+ val = field.get_default()
else:
val = field.get_default()
if is_related_object:
@@ -346,7 +353,7 @@ def __reduce__(self):
"""
data = self.__dict__
if not self._deferred:
- return (self.__class__, (), data)
+ return super(Model, self).__reduce__()
defers = []
pk_val = None
for field in self._meta.fields:
@@ -359,6 +366,7 @@ def __reduce__(self):
# once.
obj = self.__class__.__dict__[field.attname]
model = obj.model_ref()
+
return (model_unpickle, (model, defers), data)
def _get_pk_val(self, meta=None):
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11 tests/regressiontests/cache/models.py
@@ -0,0 +1,11 @@
+from django.db import models
+from datetime import datetime
+
+def expensive_calculation():
+ expensive_calculation.num_runs += 1
+ return datetime.now()
+
+class Poll(models.Model):
+ question = models.CharField(max_length=200)
+ answer = models.CharField(max_length=200)
+ pub_date = models.DateTimeField('date published', default=expensive_calculation)
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42 tests/regressiontests/cache/tests.py
@@ -16,6 +16,7 @@
from django.http import HttpResponse, HttpRequest
from django.utils.cache import patch_vary_headers, get_cache_key, learn_cache_key
from django.utils.hashcompat import md5_constructor
+from regressiontests.cache.models import Poll, expensive_calculation
# functions/classes for complex data type tests
def f():
@@ -211,6 +212,47 @@ def test_data_types(self):
self.cache.set("stuff", stuff)
self.assertEqual(self.cache.get("stuff"), stuff)
+ def test_cache_read_for_model_instance(self):
+ # Don't want fields with callable as default to be called on cache read
+ expensive_calculation.num_runs = 0
+ Poll.objects.all().delete()
+ my_poll = Poll.objects.create(question="Well?")
+ self.assertEqual(Poll.objects.count(), 1)
+ pub_date = my_poll.pub_date
+ self.cache.set('question', my_poll)
+ cached_poll = self.cache.get('question')
+ self.assertEqual(cached_poll.pub_date, pub_date)
+ # We only want the default expensive calculation run once
+ self.assertEqual(expensive_calculation.num_runs, 1)
+
+ def test_cache_write_for_model_instance_with_deferred(self):
+ # Don't want fields with callable as default to be called on cache write
+ expensive_calculation.num_runs = 0
+ Poll.objects.all().delete()
+ my_poll = Poll.objects.create(question="What?")
+ self.assertEqual(expensive_calculation.num_runs, 1)
+ defer_qs = Poll.objects.all().defer('question')
+ self.assertEqual(defer_qs.count(), 1)
+ self.assertEqual(expensive_calculation.num_runs, 1)
+ self.cache.set('deferred_queryset', defer_qs)
+ # cache set should not re-evaluate default functions
+ self.assertEqual(expensive_calculation.num_runs, 1)
+
+ def test_cache_read_for_model_instance_with_deferred(self):
+ # Don't want fields with callable as default to be called on cache read
+ expensive_calculation.num_runs = 0
+ Poll.objects.all().delete()
+ my_poll = Poll.objects.create(question="What?")
+ self.assertEqual(expensive_calculation.num_runs, 1)
+ defer_qs = Poll.objects.all().defer('question')
+ self.assertEqual(defer_qs.count(), 1)
+ self.cache.set('deferred_queryset', defer_qs)
+ self.assertEqual(expensive_calculation.num_runs, 1)
+ runs_before_cache_read = expensive_calculation.num_runs
+ cached_polls = self.cache.get('deferred_queryset')
+ # We only want the default expensive calculation run on creation and set
+ self.assertEqual(expensive_calculation.num_runs, runs_before_cache_read)
+
def test_expiration(self):
# Cache values can be set to expire
self.cache.set('expire1', 'very quickly', 1)
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