Fixed #24716 -- Deprecated Field._get_val_from_obj()

The method duplicates the functionality of Field.value_from_object()
and has the additional downside of being a privately named public
API method.

docs/howto/custom-model-fields.txt

@@ -705,15 +705,16 @@ Converting field data for serialization
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 To customize how the values are serialized by a serializer, you can override
-:meth:`~Field.value_to_string`. Calling ``Field._get_val_from_obj(obj)`` is the
-best way to get the value serialized. For example, since our ``HandField`` uses
-strings for its data storage anyway, we can reuse some existing conversion code::
+:meth:`~Field.value_to_string`. Using ``value_from_object()`` is the best way
+to get the field's value prior to serialization. For example, since our
+``HandField`` uses strings for its data storage anyway, we can reuse some
+existing conversion code::
 
     class HandField(models.Field):
         # ...
 
         def value_to_string(self, obj):
-            value = self._get_val_from_obj(obj)
+            value = self.value_from_object(obj)
             return self.get_prep_value(value)
 
 Some general advice

docs/internals/deprecation.txt

@@ -79,6 +79,9 @@ details on these changes.
 * Support for setting a URL instance namespace without an application
   namespace will be removed.
 
+* ``Field._get_val_from_obj()`` will be removed in favor of
+  ``Field.value_from_object()``.
+
 .. _deprecation-removed-in-1.10:
 
 1.10

docs/releases/1.9.txt

@@ -1001,6 +1001,9 @@ Miscellaneous
 * :class:`~django.core.signing.Signer` now issues a warning if an invalid
   separator is used. This will become an exception in Django 1.10.
 
+* ``django.db.models.Field._get_val_from_obj()`` is deprecated in favor of
+  ``Field.value_from_object()``.
+
 .. removed-features-1.9:
 
 Features removed in 1.9