When processing imports there could be the value integer 0 in fields being files (don't ask me why).
E.g. Datahandler tries to find a correspondent file object, which results in a Exception.
[BUGFIX] Avoid to get a file object with the uid zero
At some points where a file object is retrieved, a check for
the interpretation as integer is done for the method
argument only. If the argument is 0 a exception will be
thrown from the ResourceFactory.
A file object should only be fetched if the uid is an integer
greater than zero.
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Markus Klein
Tested-by: Markus Klein