Empty buckets when faceting over an EnumField or TrieIntField (5.1.0)

[Alfonso Muñoz-Pomer Fuentes]

Hi,

I’m having problems when faceting over an EnumField such as this:
<field name="kingdom" type="kingdomEnum" indexed="true" stored="true" 
required="true" />

And in enumsConfig.xml:
<?xml version="1.0" ?>
<enumsConfig>
    <enum name="kingdom">
        <value>plants</value>
        <value>metazoa</value>
        <value>fungi</value>
    </enum>
</enumsConfig>


A query such as the one below returns all buckets empty:
curl http://localhost:8983/solr/enumTest/query -d '
{
  query: "*:*",
  facet : {
    kingdom : {terms : kingdom}
  }
}'

{...
"facets":{
    "count":17,
    "kingdom":{
      "buckets":[]}}}


If I turn the kingdom field to be a string, then faceting works as 
expected. The same happens with TrieIntField (aggregating functions like 
avg work but unique doesn’t). This worked in Heliosearch. Has anybody 
had any similar problems? Am I missing something?

Thank you in advance.

Alfonso