Display Facets With 0 Values

Question

I'm working on a Lucene-based search page on Sitecore 8.1. I'd like to be able to display all facets and all facet values, even when there are 0 aggregate results for it.

Currently, what I get back from a Lucene query is

{
  "Facets": {
    "Categories": [
        {
        "Name": "facetOne",
        "Values": [
            {
            "Name": "F1Value1",
            "AggregateCount": 1,
            "Aggregate": 1
            }
        ]
        },
        {
        "Name": "facetTwo",
        "Values": [
            {
            "Name": "F2Value1",
            "AggregateCount": 2,
            "Aggregate": 2
            }
        ]
        }
    ]
    }
}

However, I'd like to get back facets with 0 values as well, such as facetThree and F2Value2 in this example:

{
  "Facets": {
    "Categories": [
        {
        "Name": "facetOne",
        "Values": [
            {
            "Name": "F1Value1",
            "AggregateCount": 1,
            "Aggregate": 1
            }
        ]
        },
        {
        "Name": "facetTwo",
        "Values": [
            {
            "Name": "F2Value1",
            "AggregateCount": 2,
            "Aggregate": 2
            },
            {
            "Name": "F2Value2",
            "AggregateCount": 0,
            "Aggregate": 0
            }
        ]
        },
        {
        "Name": "facetThree",
        "Values": [
            {
            "Name": "F3Value1",
            "AggregateCount": 0,
            "Aggregate": 0
            }
        ]
        }
    ]
    }
}

Is it possible to do this within the ContentSearch API? If so, how?

edit: here's (a simplified version of) the back-end code, in case it helps

using (IProviderSearchContext context = ContentSearchManager.GetIndex("sitecore_master_index").CreateSearchContext())
{
    var query = context.GetQueryable<TQueryable>();
    query = query
                .FacetOn(f => f.FacetOne)
                .FacetOn(f => f.FacetTwo)
                .FacetOn(f => f.FacetThree);

    var results = query.GetResults();
}

Update: I've learned that there is an override to .FacetOn that takes a "minimumResultCount" argument. That does not appear to be doing anything, however. I'm not sure if that functionality is broken, or if I'm doing something wrong.

Update 2: I submitted a support ticket to Sitecore. They have confirmed there is a bug. Essentially, the Lucene provider doesn't process the minimum result count property of the query. Sitecore has opened a bug for it and is investigating. They confirmed that it is NOT an issue for Solr, and is only limited to the Lucene implementation.

Answer 1

You need to create on /sitecore/system/Settings/Buckets/Facets a new facets add field name (must be lowercase).

You have the field Minimum Number ( Minimum Number of Items - The minimum number of items that the facet must appear in before it is shown in the search results [shared, standard value].

Set the value 0 and it will appear in your search results.