The following incorrect mapping was not detected by orm:validate-schema, instead running it resulted in:
$ doctrine orm:validate-schema
[Mapping] OK - The mapping files are correct.
<one-to-many field="duchies" target-entity="Duchy" mapped-by="realm">
<order-by-field name="name" direction="ASC" />
and the inverse side:
<one-to-one field="realm" target-entity="Realm" inversed-by="duchies">
<join-column name="Realm" referenced-column-name="ID" />
obviously, the inverse side should be many-to-one and not one-to-one. Interesting bugs in the code resulted. Obviously a coder mistake, but orm:validate-schema should have detected that the association has incompatible mappings.