Fixed #27582 -- Allowed HStoreField to store null values.

2 files changed, 6 insertions, 4 deletions

diff --git a/django/contrib/postgres/fields/hstore.py b/django/contrib/postgres/fields/hstore.py
index 76f41886a9..605deaf62c 100644
--- a/django/contrib/postgres/fields/hstore.py
+++ b/django/contrib/postgres/fields/hstore.py
@@ -13,9 +13,9 @@ __all__ = ['HStoreField']
 
 class HStoreField(Field):
     empty_strings_allowed = False
-    description = _('Map of strings to strings')
+    description = _('Map of strings to strings/nulls')
     default_error_messages = {
-        'not_a_string': _('The value of "%(key)s" is not a string.'),
+        'not_a_string': _('The value of "%(key)s" is not a string or null.'),
     }
 
     def db_type(self, connection):
@@ -30,7 +30,7 @@ class HStoreField(Field):
     def validate(self, value, model_instance):
         super(HStoreField, self).validate(value, model_instance)
         for key, val in value.items():
-            if not isinstance(val, six.string_types):
+            if not isinstance(val, six.string_types) and val is not None:
                 raise exceptions.ValidationError(
                     self.error_messages['not_a_string'],
                     code='not_a_string',
diff --git a/django/contrib/postgres/forms/hstore.py b/django/contrib/postgres/forms/hstore.py
index 4ed99d1fda..76d362999d 100644
--- a/django/contrib/postgres/forms/hstore.py
+++ b/django/contrib/postgres/forms/hstore.py
@@ -43,7 +43,9 @@ class HStoreField(forms.CharField):
 
         # Cast everything to strings for ease.
         for key, val in value.items():
-            value[key] = six.text_type(val)
+            if val is not None:
+                val = six.text_type(val)
+            value[key] = val
         return value
 
     def has_changed(self, initial, data):