[patch] XML Deserializer does not handle None values in Foreign Keys

[andrew@…]

Although the XML Serializer handle_fk_field method goes out of its way to create a 'None' element if the foreign key relation is None, the Deserializer fails to handle the case.

Example: In a Model with a self-referential Foreign key which is allowed to be blank (and null), you may have entries with a blank value. This gets mapped to the 'None' element over the wire and results in an exception when the system attempts to find the related key with primary key , since the None element contains no text.

[andrew@…]

Simple patch to handle None case.

[andrew@…]

A simple patch to detect the None element. It is not exceedingly paranoid about the XML structure, but the test should be resilient to badness (crash-wise) since it only subscripts if there is exactly one child and any child/node is guaranteed to have a nodeName, even if it turns out to be an attribute or something weird.

[Jacob]

(In [4046]) Fixed #2894: XML deserializer now correctly handles null primary keys.