A check that an entity has a field prior to checking if the field's value has changed is not being performed

Problem/Motivation

When checking to see if the value of an entity's field has changed to determine if we need to update access records, we're not first checking to see if if this particular entity has the field resulting in the following error:

Error: Call to a member function getValue() on null in reference_map_adva_entity_presave() (line 84 of modules/contrib/reference_map_adva/reference_map_adva.module)

Proposed resolution

A check that the entity has the field needs to be performed priort to checking if the value of the entity's field has changed.

Remaining tasks

• Write patch
• Review patch
• Commit