Solr faceted queries missing facet values [DATAREST-309]

Jega A opened DATAREST-309 and commented

I am working on a POC for using Solr with spring-data-solr and spring-data-rest-mvc
I have my repository defined as follows:

// Repository 
@RepositoryRestResource(collectionResourceRel = "contracts_search", path = "contracts_search")
public interface ContractRepository extends SolrCrudRepository<Contract, String> {
 
    @Query("?0")
    @Facet( fields = "product")
    FacetPage<Contract> searchAllFieldsWithFacets(@Param("searchStr") String searchStr, Pageable page);
 
}

I am executing a REST call to search for the work "Canada" using the repository.

// Query that is actually going to Solr when "searchAllFieldsWithFacets?searchStr=Canada" is executed seems right.
select?q=Canada&start=0&rows=20&facet=true&facet.mincount=1&facet.limit=10&facet.field=product&wt=javabin&version=2

// Result of the query (showing only the last section of the json result returned by the REST service).

"page" : {
    "size" : 20,
    "totalElements" : 2479,
    "totalPages" : 124,
    "number" : 0
  }

Notice how the facet result appears just as one number under "totalElements". For some reason it is not being expanded into the various values under the faceted field (i.e "product").
//The same query executed directly in the Solr Admin UI returns the correct results. Notice here how the "product" has the count for various product types.

"facet_counts": {
    "facet_queries": {},
    "facet_fields": {
      "product": [
        "Consulting",
        836,
        "Software",
        827,
        "Training",
        816
      ]
    },
    "facet_dates": {},
    "facet_ranges": {}
}

Based on some feedback from the spring-data-solr support group I wrote some test programs to check the same results by only using spring-data-solr. The following code
gives the correct results

	FacetPage<Contract> facetPage  = contractRepository.searchAllFieldsWithFacets("canada", new PageRequest(0,10));
		
	for(FacetFieldEntry entry : facetPage.getFacetResultPage("product")) {

		// eg.: Consulting, Software, Training
		System.out.println("Value: " + entry.getValue());

		// eg.: 836, 827, 816
		System.out.println("Count: " + entry.getValueCount());
	}

	System.out.println(facetPage.getFacetResultPage("product").toString());

// Results of the run
Value: Consulting
Count: 835
Value: Software
Count: 827
Value: Training
Count: 816

So the spring-data-solr by itself seems to be fetching the correct results. I am thinking that the data is being lost the layer where data is being coverted into
JSON at the spring-data-rest layer. Any suggestions on how to address this issue?

Affects: 2.1 RC1 (Dijkstra)