[1.7.x] Fixed #12030 -- Validate integer field range at the model level.

Thanks to @timgraham for the review.

Backport of 1506c71a from master

django/db/backends/__init__.py

@@ -722,6 +722,16 @@ class BaseDatabaseOperations(object):
     """
     compiler_module = "django.db.models.sql.compiler"
 
+    # Integer field safe ranges by `internal_type` as documented
+    # in docs/ref/models/fields.txt.
+    integer_field_ranges = {
+        'SmallIntegerField': (-32768, 32767),
+        'IntegerField': (-2147483648, 2147483647),
+        'BigIntegerField': (-9223372036854775808, 9223372036854775807),
+        'PositiveSmallIntegerField': (0, 32767),
+        'PositiveIntegerField': (0, 2147483647),
+    }
+
     def __init__(self, connection):
         self.connection = connection
         self._cache = None
@@ -1206,6 +1216,14 @@ class BaseDatabaseOperations(object):
         """
         return params
 
+    def integer_field_range(self, internal_type):
+        """
+        Given an integer field internal type (e.g. 'PositiveIntegerField'),
+        returns a tuple of the (min_value, max_value) form representing the
+        range of the column type bound to the field.
+        """
+        return self.integer_field_ranges[internal_type]
+
 
 # Structure returned by the DB-API cursor.description interface (PEP 249)
 FieldInfo = namedtuple('FieldInfo',

django/db/backends/mysql/base.py

@@ -223,6 +223,12 @@ class DatabaseFeatures(BaseDatabaseFeatures):
 class DatabaseOperations(BaseDatabaseOperations):
     compiler_module = "django.db.backends.mysql.compiler"
 
+    # MySQL stores positive fields as UNSIGNED ints.
+    integer_field_ranges = dict(BaseDatabaseOperations.integer_field_ranges,
+        PositiveSmallIntegerField=(0, 4294967295),
+        PositiveIntegerField=(0, 18446744073709551615),
+    )
+
     def date_extract_sql(self, lookup_type, field_name):
         # http://dev.mysql.com/doc/mysql/en/date-and-time-functions.html
         if lookup_type == 'week_day':

django/db/backends/oracle/base.py

@@ -121,6 +121,15 @@ class DatabaseFeatures(BaseDatabaseFeatures):
 class DatabaseOperations(BaseDatabaseOperations):
     compiler_module = "django.db.backends.oracle.compiler"
 
+    # Oracle uses NUMBER(11) and NUMBER(19) for integer fields.
+    integer_field_ranges = {
+        'SmallIntegerField': (-99999999999, 99999999999),
+        'IntegerField': (-99999999999, 99999999999),
+        'BigIntegerField': (-9999999999999999999, 9999999999999999999),
+        'PositiveSmallIntegerField': (0, 99999999999),
+        'PositiveIntegerField': (0, 99999999999),
+    }
+
     def autoinc_sql(self, table, column):
         # To simulate auto-incrementing primary keys in Oracle, we have to
         # create a sequence and a trigger.

django/db/backends/sqlite3/base.py

@@ -292,6 +292,10 @@ class DatabaseOperations(BaseDatabaseOperations):
             return 'django_power(%s)' % ','.join(sub_expressions)
         return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
 
+    def integer_field_range(self, internal_type):
+        # SQLite doesn't enforce any integer constraints
+        return (None, None)
+
 
 class DatabaseWrapper(BaseDatabaseWrapper):
     vendor = 'sqlite'

django/db/models/fields/__init__.py

@@ -1561,6 +1561,16 @@ class IntegerField(Field):
     }
     description = _("Integer")
 
+    def __init__(self, *args, **kwargs):
+        field_validators = kwargs.setdefault('validators', [])
+        internal_type = self.get_internal_type()
+        min_value, max_value = connection.ops.integer_field_range(internal_type)
+        if min_value is not None:
+            field_validators.append(validators.MinValueValidator(min_value))
+        if max_value is not None:
+            field_validators.append(validators.MaxValueValidator(max_value))
+        super(IntegerField, self).__init__(*args, **kwargs)
+
     def get_prep_value(self, value):
         value = super(IntegerField, self).get_prep_value(value)
         if value is None:

docs/releases/1.7.txt

@@ -678,6 +678,11 @@ Models
   Previously this used to work if the field accepted integers as input as it
   took the primary key.
 
+* Integer fields are now validated against database backend specific min and
+  max values based on their :meth:`internal_type <django.db.models.Field.get_internal_type>`.
+  Previously model field validation didn't prevent values out of their associated
+  column data type range from being saved resulting in an integrity error.
+
 Signals
 ^^^^^^^
 

tests/model_fields/models.py

@@ -57,11 +57,27 @@ class BigS(models.Model):
     s = models.SlugField(max_length=255)
 
 
-class BigInt(models.Model):
+class SmallIntegerModel(models.Model):
+    value = models.SmallIntegerField()
+
+
+class IntegerModel(models.Model):
+    value = models.IntegerField()
+
+
+class BigIntegerModel(models.Model):
     value = models.BigIntegerField()
     null_value = models.BigIntegerField(null=True, blank=True)
 
 
+class PositiveSmallIntegerModel(models.Model):
+    value = models.PositiveSmallIntegerField()
+
+
+class PositiveIntegerModel(models.Model):
+    value = models.PositiveIntegerField()
+
+
 class Post(models.Model):
     title = models.CharField(max_length=100)
     body = models.TextField()

tests/model_fields/tests.py

@@ -7,6 +7,7 @@ import warnings
 
 from django import test
 from django import forms
+from django.core import validators
 from django.core.exceptions import ValidationError
 from django.db import connection, transaction, models, IntegrityError
 from django.db.models.fields import (
@@ -21,9 +22,10 @@ from django.utils import six
 from django.utils.functional import lazy
 
 from .models import (
-    Foo, Bar, Whiz, BigD, BigS, BigInt, Post, NullBooleanModel,
+    Foo, Bar, Whiz, BigD, BigS, BigIntegerModel, Post, NullBooleanModel,
     BooleanModel, PrimaryKeyCharModel, DataModel, Document, RenamedField,
-    DateTimeModel, VerboseNameField, FksToBooleans, FkToChar, FloatModel)
+    DateTimeModel, VerboseNameField, FksToBooleans, FkToChar, FloatModel,
+    SmallIntegerModel, IntegerModel, PositiveSmallIntegerModel, PositiveIntegerModel)
 
 
 class BasicFieldTests(test.TestCase):
@@ -131,7 +133,6 @@ class DecimalFieldTests(test.TestCase):
         self.assertEqual(f._format(None), None)
 
     def test_get_db_prep_lookup(self):
-        from django.db import connection
         f = models.DecimalField(max_digits=5, decimal_places=1)
         self.assertEqual(f.get_db_prep_lookup('exact', None, connection=connection), [None])
 
@@ -212,7 +213,6 @@ class DateTimeFieldTests(unittest.TestCase):
 
 class BooleanFieldTests(unittest.TestCase):
     def _test_get_db_prep_lookup(self, f):
-        from django.db import connection
         self.assertEqual(f.get_db_prep_lookup('exact', True, connection=connection), [True])
         self.assertEqual(f.get_db_prep_lookup('exact', '1', connection=connection), [True])
         self.assertEqual(f.get_db_prep_lookup('exact', 1, connection=connection), [True])
@@ -451,33 +451,92 @@ class ValidationTest(test.TestCase):
         self.assertRaises(ValidationError, f.clean, None, None)
 
 
-class BigIntegerFieldTests(test.TestCase):
-    def test_limits(self):
-        # Ensure that values that are right at the limits can be saved
-        # and then retrieved without corruption.
-        maxval = 9223372036854775807
-        minval = -maxval - 1
-        BigInt.objects.create(value=maxval)
-        qs = BigInt.objects.filter(value__gte=maxval)
+class IntegerFieldTests(test.TestCase):
+    model = IntegerModel
+    documented_range = (-2147483648, 2147483647)
+
+    def test_documented_range(self):
+        """
+        Ensure that values within the documented safe range pass validation,
+        can be saved and retrieved without corruption.
+        """
+        min_value, max_value = self.documented_range
+
+        instance = self.model(value=min_value)
+        instance.full_clean()
+        instance.save()
+        qs = self.model.objects.filter(value__lte=min_value)
         self.assertEqual(qs.count(), 1)
-        self.assertEqual(qs[0].value, maxval)
-        BigInt.objects.create(value=minval)
-        qs = BigInt.objects.filter(value__lte=minval)
+        self.assertEqual(qs[0].value, min_value)
+
+        instance = self.model(value=max_value)
+        instance.full_clean()
+        instance.save()
+        qs = self.model.objects.filter(value__gte=max_value)
         self.assertEqual(qs.count(), 1)
-        self.assertEqual(qs[0].value, minval)
+        self.assertEqual(qs[0].value, max_value)
+
+    def test_backend_range_validation(self):
+        """
+        Ensure that backend specific range are enforced at the model
+        validation level. ref #12030.
+        """
+        field = self.model._meta.get_field('value')
+        internal_type = field.get_internal_type()
+        min_value, max_value = connection.ops.integer_field_range(internal_type)
+
+        if min_value is not None:
+            instance = self.model(value=min_value - 1)
+            expected_message = validators.MinValueValidator.message % {
+                'limit_value': min_value
+            }
+            with self.assertRaisesMessage(ValidationError, expected_message):
+                instance.full_clean()
+            instance.value = min_value
+            instance.full_clean()
+
+        if max_value is not None:
+            instance = self.model(value=max_value + 1)
+            expected_message = validators.MaxValueValidator.message % {
+                'limit_value': max_value
+            }
+            with self.assertRaisesMessage(ValidationError, expected_message):
+                instance.full_clean()
+            instance.value = max_value
+            instance.full_clean()
 
     def test_types(self):
-        b = BigInt(value=0)
-        self.assertIsInstance(b.value, six.integer_types)
-        b.save()
-        self.assertIsInstance(b.value, six.integer_types)
-        b = BigInt.objects.all()[0]
-        self.assertIsInstance(b.value, six.integer_types)
+        instance = self.model(value=0)
+        self.assertIsInstance(instance.value, six.integer_types)
+        instance.save()
+        self.assertIsInstance(instance.value, six.integer_types)
+        instance = self.model.objects.get()
+        self.assertIsInstance(instance.value, six.integer_types)
 
     def test_coercing(self):
-        BigInt.objects.create(value='10')
-        b = BigInt.objects.get(value='10')
-        self.assertEqual(b.value, 10)
+        self.model.objects.create(value='10')
+        instance = self.model.objects.get(value='10')
+        self.assertEqual(instance.value, 10)
+
+
+class SmallIntegerFieldTests(IntegerFieldTests):
+    model = SmallIntegerModel
+    documented_range = (-32768, 32767)
+
+
+class BigIntegerFieldTests(IntegerFieldTests):
+    model = BigIntegerModel
+    documented_range = (-9223372036854775808, 9223372036854775807)
+
+
+class PositiveSmallIntegerFieldTests(IntegerFieldTests):
+    model = PositiveSmallIntegerModel
+    documented_range = (0, 32767)
+
+
+class PositiveIntegerFieldTests(IntegerFieldTests):
+    model = PositiveIntegerModel
+    documented_range = (0, 2147483647)
 
 
 class TypeCoercionTests(test.TestCase):