Fix Empty InDimFilter Failure (#6330)

* fix empty InDimFilter failure (#6101)

* Add test case for empty values input

* Add documentation for empty values in InDimFilter

docs/content/querying/filters.md

@@ -213,6 +213,8 @@ The grammar for a IN filter is as follows:
 
 The IN filter supports the use of extraction functions, see [Filtering with Extraction Functions](#filtering-with-extraction-functions) for details.
 
+If an empty `values` array is passed to the IN filter, it will simply return an empty result.
+
 ### Like filter
 
 Like filters can be used for basic wildcard searches. They are equivalent to the SQL LIKE operator. Special characters

processing/src/main/java/org/apache/druid/query/filter/InDimFilter.java

@@ -77,7 +77,7 @@ public class InDimFilter implements DimFilter
   )
   {
     Preconditions.checkNotNull(dimension, "dimension can not be null");
-    Preconditions.checkArgument(values != null && !values.isEmpty(), "values can not be null or empty");
+    Preconditions.checkArgument(values != null, "values can not be null");
 
     this.values = new TreeSet<>(Comparators.naturalNullsFirst());
     for (String value : values) {

processing/src/test/java/org/apache/druid/segment/filter/InFilterTest.java

@@ -92,6 +92,11 @@ public class InFilterTest extends BaseFilterTest
   @Test
   public void testSingleValueStringColumnWithoutNulls()
   {
+    assertFilterMatches(
+        toInFilter("dim0"),
+        ImmutableList.of()
+    );
+
     assertFilterMatches(
         toInFilter("dim0", null),
         ImmutableList.of()
@@ -342,6 +347,12 @@ public class InFilterTest extends BaseFilterTest
 
   }
 
+  private DimFilter toInFilter(String dim)
+  {
+    List<String> emptyList = Lists.newArrayList();
+    return new InDimFilter(dim, emptyList, null);
+  }
+
   private DimFilter toInFilter(String dim, String value, String... values)
   {
     return new InDimFilter(dim, Lists.asList(value, values), null);