bash-4.1$ ./solr create -c solr-testing -d _default -force

WARNING: Using _default configset. Data driven schema functionality is enabled by default, which is NOT RECOMMENDED for production use.

To turn it off:

curl http://localhost:8983/solr/solr-testing/config -d '{"set-user-property": {"update.autoCreateFields":"false"}}'

ERROR: Error CREATEing SolrCore 'solr-testing': Unable to create core [solr-testing] Caused by: _root_ field must be defined using the exact same fieldType as the uniqueKey field (referenceID) uses: long