datamapper/dm-core — pull request #164 by mbj (2011-12-02 17:31:41+00:00)
Title: Raise on persisting invalid properties

This improves cases where Resource#{save,update} simply returns false
with no hint what was wrong. This mostly happens when developing custom
properties.

This patch is not complete and I'm open for discussion. This patch fixes
reporting on dm-core internal property validations, it is not related to
dm-validations.

TODOS:

* Raise a better exception, currently a plain RuntimeError is raised
* Verify the changes on specs
* Document API change.