SOLR-15078: Fix ExpandComponent behavior when expanding on numeric fields to differentiate '0' group from null group

solr/CHANGES.txt

@@ -212,7 +212,7 @@ Optimizations
 
 Bug Fixes
 ---------------------
-(No changes)
+* SOLR-15078: Fix ExpandComponent behavior when expanding on numeric fields to differentiate '0' group from null group (hossman)
 
 Other Changes
 ---------------------

solr/core/src/java/org/apache/solr/handler/component/ExpandComponent.java

@@ -71,7 +71,6 @@ import org.apache.solr.core.PluginInfo;
 import org.apache.solr.core.SolrCore;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.schema.FieldType;
-import org.apache.solr.schema.NumberType;
 import org.apache.solr.schema.SchemaField;
 import org.apache.solr.schema.StrField;
 import org.apache.solr.search.CollapsingQParserPlugin;
@@ -214,7 +213,6 @@ public class ExpandComponent extends SearchComponent implements PluginInfoInitia
     FieldType fieldType = schemaField.getType();
 
     SortedDocValues values = null;
-    long nullValue = 0L;
 
     if(fieldType instanceof StrField) {
       //Get The Top Level SortedDocValues
@@ -225,28 +223,7 @@ public class ExpandComponent extends SearchComponent implements PluginInfoInitia
       } else {
         values = DocValues.getSorted(reader, field);
       }
-    } else if (fieldType.getNumberType() != null) {
+    } else if (fieldType.getNumberType() == null) {
-      //Get the nullValue for the numeric collapse field
-      String defaultValue = searcher.getSchema().getField(field).getDefaultValue();
-      
-      final NumberType numType = fieldType.getNumberType();
-
-      // Since the expand component depends on the operation of the collapse component, 
-      // which validates that numeric field types are 32-bit,
-      // we don't need to handle invalid 64-bit field types here.
-      // FIXME: what happens when expand.field specified?
-      //  how would this work for date field?
-      //  SOLR-10400: before this, long and double were explicitly handled
-      if (defaultValue != null) {
-        if (numType == NumberType.INTEGER) {
-          nullValue = Long.parseLong(defaultValue);
-        } else if (numType == NumberType.FLOAT) {
-          nullValue = Float.floatToIntBits(Float.parseFloat(defaultValue));
-        }
-      } else if (NumberType.FLOAT.equals(numType)) { // Integer case already handled by nullValue defaulting to 0
-        nullValue = Float.floatToIntBits(0.0f);
-      }
-    } else {
       // possible if directly expand.field is specified
       throw new SolrException(SolrException.ErrorCode.BAD_REQUEST,
           "Expand not supported for fieldType:'" + fieldType.getTypeName() +"'");
@@ -358,13 +335,8 @@ public class ExpandComponent extends SearchComponent implements PluginInfoInitia
         if (valueDocID < contextDoc) {
           valueDocID = collapseValues.advance(contextDoc);
         }
-        long value;
         if (valueDocID == contextDoc) {
-          value = collapseValues.longValue();
+          final long value = collapseValues.longValue();
-        } else {
-          value = 0;
-        }
-        if(value != nullValue) {
           groupSet.add(value);
           collapsedSet.add(globalDoc);
         }
@@ -399,7 +371,7 @@ public class ExpandComponent extends SearchComponent implements PluginInfoInitia
       
       groupExpandCollector = new GroupExpandCollector(values, groupBits, collapsedSet, limit, sort);
     } else {
-      groupExpandCollector = new NumericGroupExpandCollector(field, nullValue, groupSet, collapsedSet, limit, sort);
+      groupExpandCollector = new NumericGroupExpandCollector(field, groupSet, collapsedSet, limit, sort);
     }
 
     if(groupQuery !=  null) {
@@ -628,11 +600,9 @@ public class ExpandComponent extends SearchComponent implements PluginInfoInitia
     private LongObjectHashMap<Collector> groups;
 
     private IntHashSet collapsedSet;
-    private long nullValue;
 
-    public NumericGroupExpandCollector(String field, long nullValue, LongHashSet groupSet, IntHashSet collapsedSet, int limit, Sort sort) throws IOException {
+    public NumericGroupExpandCollector(String field, LongHashSet groupSet, IntHashSet collapsedSet, int limit, Sort sort) throws IOException {
       int numGroups = collapsedSet.size();
-      this.nullValue = nullValue;
       groups = new LongObjectHashMap<>(numGroups);
       for (LongCursor cursor : groupSet) {
         groups.put(cursor.value, getCollector(limit, sort));
@@ -663,17 +633,12 @@ public class ExpandComponent extends SearchComponent implements PluginInfoInitia
 
         @Override
         public void collect(int docId) throws IOException {
-          long value;
           if (docValues.advanceExact(docId)) {
-            value = docValues.longValue();
+            final long value = docValues.longValue();
-          } else {
+            final int index = leafCollectors.indexOf(value);
-            value = 0;
+            if (index >= 0 && !collapsedSet.contains(docId + docBase)) {
-          }
+              leafCollectors.indexGet(index).collect(docId);
-          final int index;
+            }
-          if (value != nullValue && 
-              (index = leafCollectors.indexOf(value)) >= 0 && 
-              !collapsedSet.contains(docId + docBase)) {
-            leafCollectors.indexGet(index).collect(docId);
           }
         }
       };

solr/core/src/test/org/apache/solr/handler/component/DistributedExpandComponentTest.java

@@ -16,6 +16,7 @@
  */
 package org.apache.solr.handler.component;
 
+import java.util.Arrays;
 import java.util.Iterator;
 import java.util.Map;
 
@@ -26,7 +27,6 @@ import org.apache.solr.common.SolrDocumentList;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.params.ModifiableSolrParams;
 import org.junit.BeforeClass;
-import org.junit.Test;
 
 /**
  * Test for distributed ExpandComponent
@@ -44,25 +44,36 @@ public class DistributedExpandComponentTest extends BaseDistributedSearchTestCas
     initCore("solrconfig-collapseqparser.xml", "schema11.xml");
   }
 
-  @Test
   @ShardsFixed(num = 3)
   public void test() throws Exception {
-    final String group = (random().nextBoolean() ? "group_s" : "group_s_dv");
+    _test("group_s", "g1", "g2", "g3", "g4");
+    _test("group_s_dv", "g1", "g2", "g3", "g4");
+    _test("group_i", "1", "0", "3", "-1"); // NOTE: using 0 to explicitly confim we don't assume null
+    _test("group_ti_dv", "1", "-2", "0", "4"); // NOTE: using 0 to explicitly confim we don't assume null
+  }
+  
+  private void _test(final String group,
+                     final String aaa, final String bbb, final String ccc, final String ddd) throws Exception {
     
     del("*:*");
 
-    index_specific(0,"id","1", "term_s", "YYYY", group, "group1", "test_i", "5",  "test_l", "10", "test_f", "2000");
+    index_specific(0,"id","1", "term_s", "YYYY", group, aaa, "test_i", "5",  "test_l", "10", "test_f", "2000");
-    index_specific(0,"id","2", "term_s", "YYYY", group, "group1", "test_i", "50", "test_l", "100", "test_f", "200");
+    index_specific(0,"id","2", "term_s", "YYYY", group, aaa, "test_i", "50", "test_l", "100", "test_f", "200");
-    index_specific(1,"id","5", "term_s", "YYYY", group, "group2", "test_i", "4",  "test_l", "10", "test_f", "2000");
+    index_specific(1,"id","5", "term_s", "YYYY", group, bbb, "test_i", "4",  "test_l", "10", "test_f", "2000");
-    index_specific(1,"id","6", "term_s", "YYYY", group, "group2", "test_i", "10", "test_l", "100", "test_f", "200");
+    index_specific(1,"id","6", "term_s", "YYYY", group, bbb, "test_i", "10", "test_l", "100", "test_f", "200");
-    index_specific(0,"id","7", "term_s", "YYYY", group, "group1", "test_i", "1",  "test_l", "100000", "test_f", "2000");
+    index_specific(0,"id","7", "term_s", "YYYY", group, aaa, "test_i", "1",  "test_l", "100000", "test_f", "2000");
-    index_specific(1,"id","8", "term_s", "YYYY", group, "group2", "test_i", "2",  "test_l", "100000", "test_f", "200");
+    index_specific(1,"id","8", "term_s", "YYYY", group, bbb, "test_i", "2",  "test_l", "100000", "test_f", "200");
-    index_specific(2,"id","9", "term_s", "YYYY", group, "group3", "test_i", "1000", "test_l", "1005", "test_f", "3000");
+    index_specific(2,"id","9", "term_s", "YYYY", group, ccc, "test_i", "1000", "test_l", "1005", "test_f", "3000");
-    index_specific(2, "id", "10", "term_s", "YYYY", group, "group3", "test_i", "1500", "test_l", "1001", "test_f", "3200");
+    index_specific(2,"id","10","term_s", "YYYY", group, ccc, "test_i", "1500", "test_l", "1001", "test_f", "3200");
-    index_specific(2,"id", "11",  "term_s", "YYYY", group, "group3", "test_i", "1300", "test_l", "1002", "test_f", "3300");
+
-    index_specific(1,"id","12", "term_s", "YYYY", group, "group4", "test_i", "15",  "test_l", "10", "test_f", "2000");
+    // NOTE: nullPolicy=collapse will only be viable because all null docs are in collocated in shard #2
-    index_specific(1,"id","13", "term_s", "YYYY", group, "group4", "test_i", "16",  "test_l", "9", "test_f", "2000");
+    index_specific(2,"id","88", "test_i", "1001", "test_l", "1001", "test_f", "3200");
-    index_specific(1,"id","14", "term_s", "YYYY", group, "group4", "test_i", "1",  "test_l", "20", "test_f", "2000");
+    index_specific(2,"id","99", "test_i", "11", "test_l", "100", "test_f", "200");
+
+    index_specific(2,"id","11","term_s", "YYYY", group, ccc, "test_i", "1300", "test_l", "1002", "test_f", "3300");
+    index_specific(1,"id","12","term_s", "YYYY", group, ddd, "test_i", "15",  "test_l", "10", "test_f", "2000");
+    index_specific(1,"id","13","term_s", "YYYY", group, ddd, "test_i", "16",  "test_l", "9", "test_f", "2000");
+    index_specific(1,"id","14","term_s", "YYYY", group, ddd, "test_i", "1",  "test_l", "20", "test_f", "2000");
 
 
     commit();
@@ -91,7 +102,7 @@ public class DistributedExpandComponentTest extends BaseDistributedSearchTestCas
     query("q", "*:*", "start","1", "rows", "1", "fq", "{!collapse field="+group+"}", "defType", "edismax", "bf", "field(test_i)", "expand", "true", "fl","*,score");
 
     // multiple collapse and equal cost
-    ModifiableSolrParams baseParams = params("q", "*:*", "defType", "edismax", "expand", "true", "fl", "*,score",
+    ModifiableSolrParams baseParams = params("q", "term_s:YYYY", "defType", "edismax", "expand", "true", "fl", "*,score",
         "bf", "field(test_i)", "expand.sort", "id asc");
     baseParams.set("fq", "{!collapse field="+group+"}", "{!collapse field=test_i}");
     query(baseParams);
@@ -110,137 +121,185 @@ public class DistributedExpandComponentTest extends BaseDistributedSearchTestCas
     assertTrue(e.getMessage().contains("missing expand field"));
     resetExceptionIgnores();
 
-    //First basic test case.
+    // Since none of these queries will match any doc w/null in the group field, it shouldn't matter what nullPolicy is used...
-    ModifiableSolrParams params = new ModifiableSolrParams();
+    for (String np : Arrays.asList("", " nullPolicy=ignore", " nullPolicy=expand", " nullPolicy=collapse")) {
-    params.add("q", "*:*");
+      
-    params.add("fq", "{!collapse field="+group+"}");
+      //First basic test case.
-    params.add("defType", "edismax");
+      ModifiableSolrParams params = new ModifiableSolrParams();
-    params.add("bf", "field(test_i)");
+      params.add("q", "term_s:YYYY");
-    params.add("expand", "true");
+      params.add("fq", "{!collapse field="+group+np+"}");
-
+      params.add("defType", "edismax");
-    setDistributedParams(params);
+      params.add("bf", "field(test_i)");
-    QueryResponse rsp = queryServer(params);
+      params.add("expand", "true");
-    Map<String, SolrDocumentList> results = rsp.getExpandedResults();
+      
-    assertExpandGroups(results, "group1","group2", "group3", "group4");
+      setDistributedParams(params);
-    assertExpandGroupCountAndOrder("group1", 2, results, "1", "7");
+      QueryResponse rsp = queryServer(params);
-    assertExpandGroupCountAndOrder("group2", 2, results, "5", "8");
+      assertCountAndOrder(4, rsp.getResults(), "10" /* c */, "2" /* a */, "13" /* d */, "6" /* b */);
-    assertExpandGroupCountAndOrder("group3", 2, results, "11", "9");
+      Map<String, SolrDocumentList> results = rsp.getExpandedResults();
-    assertExpandGroupCountAndOrder("group4", 2, results, "12", "14");
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 2, results, "1", "7");
+      assertExpandGroupCountAndOrder(bbb, 2, results, "5", "8");
+      assertExpandGroupCountAndOrder(ccc, 2, results, "11", "9");
+      assertExpandGroupCountAndOrder(ddd, 2, results, "12", "14");
+      
+      
+      //Test expand.sort
+      
+      params = new ModifiableSolrParams();
+      params.add("q", "term_s:YYYY");
+      params.add("fq", "{!collapse field="+group+np+"}");
+      params.add("defType", "edismax");
+      params.add("bf", "field(test_i)");
+      params.add("expand", "true");
+      params.add("expand.sort", "test_l desc");
+      setDistributedParams(params);
+      rsp = queryServer(params);
+      assertCountAndOrder(4, rsp.getResults(), "10" /* c */, "2" /* a */, "13" /* d */, "6" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 2, results, "7", "1");
+      assertExpandGroupCountAndOrder(bbb, 2, results, "8", "5");
+      assertExpandGroupCountAndOrder(ccc, 2, results, "9", "11");
+      assertExpandGroupCountAndOrder(ddd, 2, results, "14", "12");
 
 
-    //Test expand.sort
+      //Test expand.rows
+      
+      params = new ModifiableSolrParams();
+      params.add("q", "term_s:YYYY");
+      params.add("fq", "{!collapse field="+group+np+"}");
+      params.add("defType", "edismax");
+      params.add("bf", "field(test_i)");
+      params.add("expand", "true");
+      params.add("expand.sort", "test_l desc");
+      params.add("expand.rows", "1");
+      setDistributedParams(params);
+      rsp = queryServer(params);
+      assertCountAndOrder(4, rsp.getResults(), "10" /* c */, "2" /* a */, "13" /* d */, "6" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 1, results, "7");
+      assertExpandGroupCountAndOrder(bbb, 1, results, "8");
+      assertExpandGroupCountAndOrder(ccc, 1, results, "9");
+      assertExpandGroupCountAndOrder(ddd, 1, results, "14");
+      
+      //Test expand.rows = 0 - no docs only expand count
+      
+      params = new ModifiableSolrParams();
+      params.add("q", "term_s:YYYY");
+      params.add("fq", "{!collapse field="+group+np+"}");
+      params.add("defType", "edismax");
+      params.add("bf", "field(test_i)");
+      params.add("expand", "true");
+      params.add("expand.rows", "0");
+      params.add("fl", "id");
+      setDistributedParams(params);
+      rsp = queryServer(params);
+      assertCountAndOrder(4, rsp.getResults(), "10" /* c */, "2" /* a */, "13" /* d */, "6" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 0, results);
+      assertExpandGroupCountAndOrder(bbb, 0, results);
+      assertExpandGroupCountAndOrder(ccc, 0, results);
+      assertExpandGroupCountAndOrder(ddd, 0, results);
+      
+      //Test expand.rows = 0 with expand.field
+      
+      params = new ModifiableSolrParams();
+      params.add("q", "term_s:YYYY");
+      params.add("fq", "test_l:10");
+      params.add("defType", "edismax");
+      params.add("bf", "field(test_i)");
+      params.add("expand", "true");
+      params.add("expand.fq", "test_f:2000");
+      params.add("expand.field", group);
+      params.add("expand.rows", "0");
+      params.add("fl", "id,score");
+      setDistributedParams(params);
+      rsp = queryServer(params);
+      assertCountAndOrder(3, rsp.getResults(), "12" /* d */, "1" /* a */, "5" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, ddd);
+      assertExpandGroupCountAndOrder(aaa, 0, results);
+      assertExpandGroupCountAndOrder(ddd, 0, results);
+      
+      //Test key-only fl
+      
+      params = new ModifiableSolrParams();
+      params.add("q", "term_s:YYYY");
+      params.add("fq", "{!collapse field="+group+np+"}");
+      params.add("defType", "edismax");
+      params.add("bf", "field(test_i)");
+      params.add("expand", "true");
+      params.add("fl", "id");
+      
+      setDistributedParams(params);
+      rsp = queryServer(params);
+      assertCountAndOrder(4, rsp.getResults(), "10" /* c */, "2" /* a */, "13" /* d */, "6" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 2, results, "1", "7");
+      assertExpandGroupCountAndOrder(bbb, 2, results, "5", "8");
+      assertExpandGroupCountAndOrder(ccc, 2, results, "11", "9");
+      assertExpandGroupCountAndOrder(ddd, 2, results, "12", "14");
+      
+      //Test distrib.singlePass true
+      
+      params = new ModifiableSolrParams();
+      params.add("q", "term_s:YYYY");
+      params.add("fq", "{!collapse field="+group+np+"}");
+      params.add("defType", "edismax");
+      params.add("bf", "field(test_i)");
+      params.add("expand", "true");
+      params.add("distrib.singlePass", "true");
+      
+      setDistributedParams(params);
+      rsp = queryServer(params);
+      assertCountAndOrder(4, rsp.getResults(), "10" /* c */, "2" /* a */, "13" /* d */, "6" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 2, results, "1", "7");
+      assertExpandGroupCountAndOrder(bbb, 2, results, "5", "8");
+      assertExpandGroupCountAndOrder(ccc, 2, results, "11", "9");
+      assertExpandGroupCountAndOrder(ddd, 2, results, "12", "14");
+    }
 
-    params = new ModifiableSolrParams();
+    { // queries matching all docs to test null groups from collapse and how it affects expand
-    params.add("q", "*:*");
+
-    params.add("fq", "{!collapse field="+group+"}");
+      ModifiableSolrParams params = new ModifiableSolrParams();
-    params.add("defType", "edismax");
+      params.add("q", "*:*");
-    params.add("bf", "field(test_i)");
+      params.add("defType", "edismax");
-    params.add("expand", "true");
+      params.add("bf", "field(test_i)");
-    params.add("expand.sort", "test_l desc");
+      params.add("expand", "true");
-    setDistributedParams(params);
+      setDistributedParams(params);
-    rsp = queryServer(params);
+
-    results = rsp.getExpandedResults();
+      // nullPolicy=expand
-    assertExpandGroups(results, "group1","group2", "group3", "group4");
+      params.add("fq", "{!collapse field="+group+" nullPolicy=expand}");
-    assertExpandGroupCountAndOrder("group1", 2, results, "7", "1");
+      
-    assertExpandGroupCountAndOrder("group2", 2, results, "8", "5");
+      QueryResponse rsp = queryServer(params);
-    assertExpandGroupCountAndOrder("group3", 2, results, "9", "11");
+      assertCountAndOrder(6, rsp.getResults(), "10" /* c */, "88" /* null */, "2" /* a */, "13" /* d */, "99" /* null */, "6" /* b */);
-    assertExpandGroupCountAndOrder("group4", 2, results, "14", "12");
+      Map<String, SolrDocumentList> results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 2, results, "1", "7");
+      assertExpandGroupCountAndOrder(bbb, 2, results, "5", "8");
+      assertExpandGroupCountAndOrder(ccc, 2, results, "11", "9");
+      assertExpandGroupCountAndOrder(ddd, 2, results, "12", "14");
+
+      // nullPolicy=collapse
+      params.set("fq", "{!collapse field="+group+" nullPolicy=collapse}");
+      
+      rsp = queryServer(params);
+      assertCountAndOrder(5, rsp.getResults(), "10" /* c */, "88" /* null */, "2" /* a */, "13" /* d */, "6" /* b */);
+      results = rsp.getExpandedResults();
+      assertExpandGroups(results, aaa, bbb, ccc, ddd);
+      assertExpandGroupCountAndOrder(aaa, 2, results, "1", "7");
+      assertExpandGroupCountAndOrder(bbb, 2, results, "5", "8");
+      assertExpandGroupCountAndOrder(ccc, 2, results, "11", "9");
+      assertExpandGroupCountAndOrder(ddd, 2, results, "12", "14");
 
 
-    //Test expand.rows
+    }
-
+    
-    params = new ModifiableSolrParams();
-    params.add("q", "*:*");
-    params.add("fq", "{!collapse field="+group+"}");
-    params.add("defType", "edismax");
-    params.add("bf", "field(test_i)");
-    params.add("expand", "true");
-    params.add("expand.sort", "test_l desc");
-    params.add("expand.rows", "1");
-    setDistributedParams(params);
-    rsp = queryServer(params);
-    results = rsp.getExpandedResults();
-    assertExpandGroups(results, "group1","group2", "group3", "group4");
-    assertExpandGroupCountAndOrder("group1", 1, results, "7");
-    assertExpandGroupCountAndOrder("group2", 1, results, "8");
-    assertExpandGroupCountAndOrder("group3", 1, results, "9");
-    assertExpandGroupCountAndOrder("group4", 1, results, "14");
-
-    //Test expand.rows = 0 - no docs only expand count
-
-    params = new ModifiableSolrParams();
-    params.add("q", "*:*");
-    params.add("fq", "{!collapse field="+group+"}");
-    params.add("defType", "edismax");
-    params.add("bf", "field(test_i)");
-    params.add("expand", "true");
-    params.add("expand.rows", "0");
-    params.add("fl", "id");
-    setDistributedParams(params);
-    rsp = queryServer(params);
-    results = rsp.getExpandedResults();
-    assertExpandGroups(results, "group1","group2", "group3", "group4");
-    assertExpandGroupCountAndOrder("group1", 0, results);
-    assertExpandGroupCountAndOrder("group2", 0, results);
-    assertExpandGroupCountAndOrder("group3", 0, results);
-    assertExpandGroupCountAndOrder("group4", 0, results);
-
-    //Test expand.rows = 0 with expand.field
-
-    params = new ModifiableSolrParams();
-    params.add("q", "*:*");
-    params.add("fq", "test_l:10");
-    params.add("defType", "edismax");
-    params.add("expand", "true");
-    params.add("expand.fq", "test_f:2000");
-    params.add("expand.field", group);
-    params.add("expand.rows", "0");
-    params.add("fl", "id,score");
-    setDistributedParams(params);
-    rsp = queryServer(params);
-    results = rsp.getExpandedResults();
-    assertExpandGroups(results, "group1", "group4");
-    assertExpandGroupCountAndOrder("group1", 0, results);
-    assertExpandGroupCountAndOrder("group4", 0, results);
-
-    //Test key-only fl
-
-    params = new ModifiableSolrParams();
-    params.add("q", "*:*");
-    params.add("fq", "{!collapse field="+group+"}");
-    params.add("defType", "edismax");
-    params.add("bf", "field(test_i)");
-    params.add("expand", "true");
-    params.add("fl", "id");
-
-    setDistributedParams(params);
-    rsp = queryServer(params);
-    results = rsp.getExpandedResults();
-    assertExpandGroups(results, "group1","group2", "group3", "group4");
-    assertExpandGroupCountAndOrder("group1", 2, results, "1", "7");
-    assertExpandGroupCountAndOrder("group2", 2, results, "5", "8");
-    assertExpandGroupCountAndOrder("group3", 2, results, "11", "9");
-    assertExpandGroupCountAndOrder("group4", 2, results, "12", "14");
-
-    //Test distrib.singlePass true
-
-    params = new ModifiableSolrParams();
-    params.add("q", "*:*");
-    params.add("fq", "{!collapse field="+group+"}");
-    params.add("defType", "edismax");
-    params.add("bf", "field(test_i)");
-    params.add("expand", "true");
-    params.add("distrib.singlePass", "true");
-
-    setDistributedParams(params);
-    rsp = queryServer(params);
-    results = rsp.getExpandedResults();
-    assertExpandGroups(results, "group1","group2", "group3", "group4");
-    assertExpandGroupCountAndOrder("group1", 2, results, "1", "7");
-    assertExpandGroupCountAndOrder("group2", 2, results, "5", "8");
-    assertExpandGroupCountAndOrder("group3", 2, results, "11", "9");
-    assertExpandGroupCountAndOrder("group4", 2, results, "12", "14");
-
   }
 
   private void assertExpandGroups(Map<String, SolrDocumentList> expandedResults, String... groups) throws Exception {
@@ -264,12 +323,17 @@ public class DistributedExpandComponentTest extends BaseDistributedSearchTestCas
     return buf.toString();
   }
 
-  private void assertExpandGroupCountAndOrder(String group, int count, Map<String, SolrDocumentList>expandedResults, String... docs) throws Exception {
+  private void assertExpandGroupCountAndOrder(final String group, final int count,
+                                              final Map<String, SolrDocumentList>expandedResults,
+                                              final String... docs) throws Exception {
     SolrDocumentList results = expandedResults.get(group);
     if(results == null) {
       throw new Exception("Group Not Found:"+group);
     }
-
+    assertCountAndOrder(count, results, docs);
+  }
+  private void assertCountAndOrder(final int count, final SolrDocumentList results,
+                                   final String... docs) throws Exception {
     if(results.size() != count) {
       throw new Exception("Expected Count "+results.size()+" Not Found:"+count);
     }

solr/core/src/test/org/apache/solr/handler/component/TestExpandComponent.java

@@ -16,10 +16,8 @@
  */
 package org.apache.solr.handler.component;
 
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.List;
 
 import org.apache.solr.SolrTestCaseJ4;
 import org.apache.solr.common.SolrException;
@@ -46,50 +44,50 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     assertU(commit());
   }
 
-  @Test
+  private static String maybeTopFc() {
-  public void testExpand() throws Exception {
+    return (random().nextBoolean() ? " hint="+ CollapsingQParserPlugin.HINT_TOP_FC : "");
-    List<String> groups = new ArrayList<>();
-    groups.add("group_s");
-    groups.add("group_s_dv");
-
-    Collections.shuffle(groups, random());
-    String floatAppend = "";
-
-    String hint = (random().nextBoolean() ? " hint="+ CollapsingQParserPlugin.HINT_TOP_FC : "");
-
-    _testExpand(groups.get(0), floatAppend, hint);
   }
-
+  private static String floatAppend() {
-  @Test
+    String floatAppend = "."+random().nextInt(100);  //Append the float
-  public void testNumericExpand() throws Exception {
+    floatAppend = Float.toString(Float.parseFloat(floatAppend)); //Create a proper float out of the string.
-    List<String> groups = new ArrayList<>();
+    floatAppend = floatAppend.substring(1);  //Drop off the leading 0, leaving just the decimal
-    groups.add("group_i");
+    return floatAppend;
-    groups.add("group_ti_dv");
-    groups.add("group_f");
-    groups.add("group_tf_dv");
-    Collections.shuffle(groups, random());
-    String floatAppend = "";
-    if(groups.get(0).indexOf("f") > -1) {
-      floatAppend = "."+random().nextInt(100);  //Append the float
-      floatAppend = Float.toString(Float.parseFloat(floatAppend)); //Create a proper float out of the string.
-      floatAppend = floatAppend.substring(1);  //Drop off the leading 0, leaving just the decimal
-    }
-
-    String hint = "";
-
-    _testExpand(groups.get(0), floatAppend, hint);
   }
-
+  
+  public void testString() throws Exception {
+    _testExpand("group_s", "", maybeTopFc());
+  }
+  public void testStringDv() throws Exception {
+    _testExpand("group_s_dv", "", maybeTopFc());
+  }
+ 
+  public void testInt() throws Exception {
+    _testExpand("group_i", "", "");
+  }
+  public void testIntDv() throws Exception {
+    _testExpand("group_ti_dv", "", "");
+  }
+  
+  public void testFloat() throws Exception {
+    _testExpand("group_f", floatAppend(), "");
+    _testExpand("group_f", ".0", ""); // explicit 0 check for 0 vs null group
+  }
+  public void testFloatDv() throws Exception {
+    _testExpand("group_tf_dv", floatAppend(), "");
+    _testExpand("group_tf_dv", ".0", ""); // explicit 0 check for 0 vs null group
+  }
+  
   private void _testExpand(String group, String floatAppend, String hint) throws Exception {
+    // NOTE: one of our groups uses '0' as the group value to explicitly check numeric expand for 0 vs null group behavior
     String[][] docs = {
         {"id","1", "term_s", "YYYY", group, "1"+floatAppend, "test_i", "5", "test_l", "10", "test_f", "2000", "type_s", "parent"},
         {"id","2", "term_s","YYYY", group, "1"+floatAppend, "test_i", "50", "test_l", "100", "test_f", "200", "type_s", "child"},
         {"id","3", "term_s", "YYYY", "test_i", "5000", "test_l", "100", "test_f", "200"},
         {"id","4", "term_s", "YYYY", "test_i", "500", "test_l", "1000", "test_f", "2000"},
-        {"id","5", "term_s", "YYYY", group, "2"+floatAppend, "test_i", "4", "test_l", "10", "test_f", "2000", "type_s", "parent"},
+        {"id","5", "term_s", "YYYY", group, "0"+floatAppend, "test_i", "4", "test_l", "10", "test_f", "2000", "type_s", "parent"},
-        {"id","6", "term_s","YYYY", group, "2"+floatAppend, "test_i", "10", "test_l", "100", "test_f", "200", "type_s", "child"},
+        {"id","6", "term_s","YYYY", group, "0"+floatAppend, "test_i", "10", "test_l", "100", "test_f", "200", "type_s", "child"},
         {"id","7", "term_s", "YYYY", group, "1"+floatAppend, "test_i", "1", "test_l", "100000", "test_f", "2000", "type_s", "child"},
-        {"id","8", "term_s","YYYY", group, "2"+floatAppend, "test_i", "2", "test_l",  "100000", "test_f", "200", "type_s", "child"}
+        {"id","8", "term_s","YYYY", group, "0"+floatAppend, "test_i", "2", "test_l",  "100000", "test_f", "200", "type_s", "child"}
     };
     createIndex(docs);
 
@@ -107,8 +105,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='1']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='7']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='8']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='8']"
     );
 
     //Basic test case page 2
@@ -116,8 +114,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     assertQ(req(params, "rows", "1", "start", "1"), "*[count(/response/result/doc)=1]",
         "*[count(/response/lst[@name='expanded']/result)=1]",
         "/response/result/doc[1]/str[@name='id'][.='6']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='8']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='8']"
     );
 
     //Test expand.sort
@@ -129,12 +127,12 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='1']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='5']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='5']"
     );
 
     //Test with nullPolicy, ExpandComponent should ignore docs with null values in the collapse fields.
-    //Main result set should include the doc with null value in the collapse field.
+    //Main result set should include the doc(s) with null value in the collapse field.
     params = new ModifiableSolrParams();
     params.add("q", "*:*");
     params.add("fq", "{!collapse field="+group+hint+" nullPolicy=collapse}");
@@ -149,8 +147,20 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[3]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='1']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='5']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='5']"
+    );
+    params.set("fq", "{!collapse field="+group+hint+" nullPolicy=expand}");
+    assertQ(req(params), "*[count(/response/result/doc)=4]",
+        "*[count(/response/lst[@name='expanded']/result)=2]",
+        "/response/result/doc[1]/str[@name='id'][.='3']",
+        "/response/result/doc[2]/str[@name='id'][.='4']",
+        "/response/result/doc[3]/str[@name='id'][.='2']",
+        "/response/result/doc[4]/str[@name='id'][.='6']",
+        "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
+        "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='1']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='5']"
     );
 
 
@@ -169,8 +179,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='5']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='2']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='6']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='6']"
     );
 
 
@@ -190,8 +200,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='5']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='2']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='6']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='6']"
     );
 
     //Test override expand.fq and expand.q
@@ -211,8 +221,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='5']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='2']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='6']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='6']"
     );
 
     //Test expand.rows
@@ -227,11 +237,11 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     assertQ(req(params), "*[count(/response/result/doc)=2]",
         "*[count(/response/lst[@name='expanded']/result)=2]",
         "*[count(/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc)=1]",
-        "*[count(/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc)=1]",
+        "*[count(/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc)=1]",
         "/response/result/doc[1]/str[@name='id'][.='2']",
         "/response/result/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']"
     );
 
     //Test expand.rows = 0 - no docs only expand count
@@ -245,7 +255,7 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     assertQ(req(params), "*[count(/response/result/doc)=2]",
             "*[count(/response/lst[@name='expanded']/result)=2]",
             "*[count(/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc)=0]",
-            "*[count(/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc)=0]",
+            "*[count(/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc)=0]",
             "/response/result/doc[1]/str[@name='id'][.='2']",
             "/response/result/doc[2]/str[@name='id'][.='6']"
     );
@@ -263,7 +273,7 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     assertQ(req(params, "fl", "id"), "*[count(/response/result/doc)=2]",
             "*[count(/response/lst[@name='expanded']/result)=2]",
             "*[count(/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc)=0]",
-            "*[count(/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc)=0]",
+            "*[count(/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc)=0]",
             "/response/result/doc[1]/str[@name='id'][.='1']",
             "/response/result/doc[2]/str[@name='id'][.='5']"
     );
@@ -281,7 +291,7 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     assertQ(req(params, "fl", "id,score"), "*[count(/response/result/doc)=2]",
             "*[count(/response/lst[@name='expanded']/result)=2]",
             "*[count(/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc)=0]",
-            "*[count(/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc)=0]",
+            "*[count(/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc)=0]",
             "*[count(/response/lst[@name='expanded']/result[@maxScore])=0]", //maxScore should not be available
             "/response/result/doc[1]/str[@name='id'][.='1']",
             "/response/result/doc[2]/str[@name='id'][.='5']",
@@ -330,8 +340,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='1']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='7']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='8']",
         "count(//*[@name='score'])=0" // score shouldn't be returned when not requested
     );
 
@@ -342,8 +352,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='1']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='7']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='8']",
         "count(//*[@name='score' and .='NaN'])=0"
     );
 
@@ -356,8 +366,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='1']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='7']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='8']",
         "count(//*[@name='score' and .='NaN'])=0"
     );
 
@@ -370,8 +380,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         // note that the expanded docs are score descending order (score is 1 test_i)
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='1']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='5']",
         "count(//*[@name='score' and .='NaN'])=0",
         "count(/response/lst[@name='expanded']/result/doc[number(*/@name='score')!=number(*/@name='test_i')])=0"
     );
@@ -385,8 +395,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         // note that the expanded docs are score descending order (score is 1 test_i)
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='7']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='1']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='8']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='5']",
         "count(//*[@name='score' and .='NaN'])=0",
         "count(/response/lst[@name='expanded']/result/doc[number(*/@name='score')!=number(*/@name='test_i')])=0"
     );
@@ -408,7 +418,7 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
     );
 
     // Support expand enabled without previous collapse
-    assertQ(req("q", "type_s:child", "sort", group+" asc, test_l desc", "defType", "edismax",
+    assertQ(req("q", "type_s:child", "sort", group+" desc, test_l desc", "defType", "edismax",
         "expand", "true", "expand.q", "type_s:parent", "expand.field", group),
         "*[count(/response/result/doc)=4]",
         "*[count(/response/lst[@name='expanded']/result)=2]",
@@ -417,7 +427,7 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "/response/result/doc[3]/str[@name='id'][.='8']",
         "/response/result/doc[4]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='1']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']"
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']"
     );
 
     // With multiple collapse
@@ -456,8 +466,8 @@ public class TestExpandComponent extends SolrTestCaseJ4 {
         "*[count(/response/result/doc)=2]",
         "/response/result/doc[1]/str[@name='id'][.='8']",
         "/response/result/doc[2]/str[@name='id'][.='7']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[1]/str[@name='id'][.='5']",
-        "/response/lst[@name='expanded']/result[@name='2"+floatAppend+"']/doc[2]/str[@name='id'][.='6']",
+        "/response/lst[@name='expanded']/result[@name='0"+floatAppend+"']/doc[2]/str[@name='id'][.='6']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[1]/str[@name='id'][.='1']",
         "/response/lst[@name='expanded']/result[@name='1"+floatAppend+"']/doc[2]/str[@name='id'][.='2']"
     );

solr/core/src/test/org/apache/solr/search/TestBlockCollapse.java

@@ -818,7 +818,6 @@ public class TestBlockCollapse extends SolrTestCaseJ4 {
    * (and the other tests should adequeately prove that the block hueristics for _root_ collapsing work)
    */
   public void testBlockCollapseWithExpandComponent() throws Exception {
-    // NOTE: due to SOLR-15078 we don't bother trying to collapse/expand on int in this test
 
     { // convert our docs + some docs w/o collapse fields, along with some commits, to update commands
       // in a shuffled order and process all of them...
@@ -839,10 +838,10 @@ public class TestBlockCollapse extends SolrTestCaseJ4 {
     // we don't bother testing _root_ field collapsing, since it contains different field values then block_s1
     for (String opt : Arrays.asList(// no block collapse logic used (sanity checks)
                                     "field=block_s1",            
-                                    // "field=block_i", // TODO: SOLR-15078
+                                    "field=block_i",
 
                                     // block collapse used explicitly (int)
-                                    // "field=block_i  hint=block", // TODO: SOLR-15078
+                                    "field=block_i  hint=block",
                                     
                                     // block collapse used explicitly (ord)
                                     "field=block_s1 hint=block"