The reason was a synchronization issue.
Actually "LayerPropertiesNodeRef" is not a reference, but
a mirror copy of the LayerPropertiesNode the reference points
to. Changes to the original must be synchronized into the
reference and back.
This concept is a tribute to the original implementation and
the node reference was a convenience add-on to the iterator-
based API.
Better solution in general is to replace the LayerPropertiesNodeRef
concept with a real reference.
In addition, this fix includes Python-related fixes: because
of the short lifetime of Python references, the functionality
was not as expected sometimes. Keeping copies of LayerPropertiesIterators
helped. Some tweaks were required to maintain the delete() semantics.
- Include a copy of the unit test framework so we're no longer
depending on incompatible versions for Ruby 1 and 2.
- Avoid duplication of path entries in unit tests