Disabling point range collector if doc values not indexed (#14559)

---------
Signed-off-by: Ankit Jain <[email protected]>

Author: jainankitk

lucene/benchmark-jmh/src/java/org/apache/lucene/benchmark/jmh/HistogramCollectorBenchmark.java

@@ -75,6 +75,8 @@ public void setup(BenchmarkParams params) throws Exception {
       if (params.pointEnabled) {
         // Adding indexed point field to verify multi range collector
         doc.add(new LongPoint("f", value));
+        // Doc values need to be enabled for histogram collection
+        doc.add(NumericDocValuesField.indexedField("f", value));
       } else {
         doc.add(NumericDocValuesField.indexedField("f", value));
       }

lucene/sandbox/src/java/org/apache/lucene/sandbox/facet/plain/histograms/HistogramCollector.java

@@ -73,6 +73,13 @@ public LeafCollector getLeafCollector(LeafReaderContext context) throws IOExcept
       throw new CollectionTerminatedException();
     }
 
+    // Doc values should be indexed to enable histogram collection
+    if (fi.getDocValuesType() != DocValuesType.NUMERIC
+        && fi.getDocValuesType() != DocValuesType.SORTED_NUMERIC) {
+      throw new IllegalStateException(
+          "Expected numeric field, but got doc-value type: " + fi.getDocValuesType());
+    }
+
     // We can use multi range traversal logic to collect the histogram on numeric
     // field indexed as point for MATCH_ALL cases. In future, this can be extended
     // for Point Range Query cases as well
@@ -92,12 +99,6 @@ public LeafCollector getLeafCollector(LeafReaderContext context) throws IOExcept
       }
     }
 
-    if (fi.getDocValuesType() != DocValuesType.NUMERIC
-        && fi.getDocValuesType() != DocValuesType.SORTED_NUMERIC) {
-      throw new IllegalStateException(
-          "Expected numeric field, but got doc-value type: " + fi.getDocValuesType());
-    }
-
     SortedNumericDocValues values = DocValues.getSortedNumeric(context.reader(), field);
     NumericDocValues singleton = DocValues.unwrapSingleton(values);
     if (singleton == null) {

lucene/sandbox/src/test/org/apache/lucene/sandbox/facet/plain/histograms/TestHistogramCollectorManager.java

@@ -125,23 +125,8 @@ public void testSkipIndexWithSortAndLowInterval() throws IOException {
 
   public void testMultiRangePointTreeCollector() throws IOException {
     Directory dir = newDirectory();
-    IndexWriter w = new IndexWriter(dir, new IndexWriterConfig());
-
-    long[] values = new long[5000];
-
-    for (int i = 0; i < values.length; i++) {
-      values[i] = random().nextInt(0, 5000); // Generates a random integer
-    }
-
-    for (long value : values) {
-      Document doc = new Document();
-      // Adding indexed point field to verify multi range collector
-      doc.add(new LongPoint("f", value));
-      w.addDocument(doc);
-    }
-
-    DirectoryReader reader = DirectoryReader.open(w);
-    w.close();
+    long[] values = generateRandomData(5000);
+    DirectoryReader reader = indexNumericData(dir, values, true);
     IndexSearcher searcher = newSearcher(reader);
 
     // Validate the MATCH_ALL case
@@ -222,6 +207,50 @@ protected String toString(int dimension, byte[] value) {
     dir.close();
   }
 
+  public void testHistogramCollectorExceptionWithoutDocValues() throws IOException {
+    Directory dir = newDirectory();
+    long[] values = generateRandomData(5000);
+    DirectoryReader reader = indexNumericData(dir, values, false);
+    IndexSearcher searcher = newSearcher(reader);
+
+    // Validate that exception is thrown when doc values is disabled on numeric field
+    expectThrows(
+        IllegalStateException.class,
+        () -> searcher.search(new MatchAllDocsQuery(), new HistogramCollectorManager("f", 1000)));
+
+    reader.close();
+    dir.close();
+  }
+
+  private long[] generateRandomData(int bound) {
+    long[] values = new long[bound];
+    for (int i = 0; i < values.length; i++) {
+      values[i] = random().nextInt(0, bound); // Generates a random integer
+    }
+    return values;
+  }
+
+  private DirectoryReader indexNumericData(Directory dir, long[] values, boolean docValueEnabled)
+      throws IOException {
+    IndexWriter w = new IndexWriter(dir, new IndexWriterConfig());
+
+    for (long value : values) {
+      Document doc = new Document();
+      // Adding indexed point field to verify multi range collector
+      doc.add(new LongPoint("f", value));
+      if (docValueEnabled) {
+        // Doc values need to be enabled for histogram collection
+        doc.add(new NumericDocValuesField("f", value));
+      }
+      w.addDocument(doc);
+    }
+
+    DirectoryReader reader = DirectoryReader.open(w);
+    w.close();
+
+    return reader;
+  }
+
   private void doTestSkipIndex(IndexWriterConfig cfg) throws IOException {
     Directory dir = newDirectory();
     IndexWriter w = new IndexWriter(dir, cfg);