id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
21203	Potential data corruption issue with Oracle and Mysql due to SQLCompiler.resolve_columns row, fields misalignment when using defer and select_related	Michael Manfre	nobody	"SQLCompiler.resolve_columns fields, values are misaligned with defer and select_related. Same data corruption issue as reported/fixed by issue #21126.

Given:
{{{
class Parent(models.Model):
	parentid = models.AutoField(primary_key=True)
	parent_bool = models.BooleanField(default=True)
	created = models.DateTimeField(auto_now=True)

class Child(models.Model):
	childid = models.AutoField(primary_key=True)
	parent = models.ForeignKey(Parent)
}}}

The following query
{{{
p = Parent.objects.create(parent_bool=True)
c = Child.objects.create(parent=p)

qs = Child.objects.all().select_related('parent').defer('parent__parent_bool')

}}}

will result in this field misalignment

{{{
        field=<django.db.models.fields.AutoField: childid>      value=1
        field=<django.db.models.fields.related.ForeignKey: parent>      value=1
        field=<django.db.models.fields.AutoField: parentid>     value=1
        field=<django.db.models.fields.BooleanField: parent_bool>       value=datetime.datetime(2013, 9, 30, 19, 59, 41, 490000, tzinfo=<UTC>)
        field=<django.db.models.fields.DateTimeField: created>  value=None

}}}


'''parent_bool''' should have been removed from fields, but it was not because '''results_iter''' doesn't properly compare the '''only_load''' fields to the correct '''db_table'''^1^.

^1^ https://github.com/django/django/blob/master/django/db/models/sql/compiler.py#L716"	Bug	closed	Database layer (models, ORM)	1.5	Release blocker	fixed		Anssi Kääriäinen	Ready for checkin	0	0	0	0	0	0