Fix NPE when LeafReader return null VectorValues

lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/lucene94/Lucene94HnswVectorsReader.java

@@ -254,7 +254,7 @@ public ByteVectorValues getByteVectorValues(String field) throws IOException {
               + "\" is encoded as: "
               + fieldEntry.vectorEncoding
               + " expected: "
-              + VectorEncoding.FLOAT32);
+              + VectorEncoding.BYTE);
     }
     return OffHeapByteVectorValues.load(fieldEntry, vectorData);
   }

lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/lucene95/Lucene95HnswVectorsReader.java

@@ -270,7 +270,7 @@ public ByteVectorValues getByteVectorValues(String field) throws IOException {
               + "\" is encoded as: "
               + fieldEntry.vectorEncoding
               + " expected: "
-              + VectorEncoding.FLOAT32);
+              + VectorEncoding.BYTE);
     }
     return OffHeapByteVectorValues.load(
         fieldEntry.ordToDocVectorValues,

lucene/core/src/java/org/apache/lucene/codecs/lucene99/Lucene99FlatVectorsReader.java

@@ -232,7 +232,7 @@ public ByteVectorValues getByteVectorValues(String field) throws IOException {
               + "\" is encoded as: "
               + fieldEntry.vectorEncoding
               + " expected: "
-              + VectorEncoding.FLOAT32);
+              + VectorEncoding.BYTE);
     }
     return OffHeapByteVectorValues.load(
         fieldEntry.ordToDoc,

lucene/core/src/java/org/apache/lucene/index/ByteVectorValues.java

@@ -54,4 +54,25 @@ public final long cost() {
    * @return the vector value
    */
   public abstract byte[] vectorValue() throws IOException;
+
+  /**
+   * Checks the Vector Encoding of a field
+   *
+   * @throws IllegalStateException if {@code field} has vectors, but using a different encoding
+   * @lucene.internal
+   * @lucene.experimental
+   */
+  public static void checkField(LeafReader in, String field) {
+    FieldInfo fi = in.getFieldInfos().fieldInfo(field);
+    if (fi != null && fi.hasVectorValues() && fi.getVectorEncoding() != VectorEncoding.BYTE) {
+      throw new IllegalStateException(
+          "Unexpected vector encoding ("
+              + fi.getVectorEncoding()
+              + ") for field "
+              + field
+              + "(expected="
+              + VectorEncoding.BYTE
+              + ")");
+    }
+  }
 }

lucene/core/src/java/org/apache/lucene/index/CodecReader.java

@@ -246,7 +246,9 @@ public final void searchNearestVectors(
       String field, float[] target, KnnCollector knnCollector, Bits acceptDocs) throws IOException {
     ensureOpen();
     FieldInfo fi = getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
+    if (fi == null
+        || fi.getVectorDimension() == 0
+        || fi.getVectorEncoding() != VectorEncoding.FLOAT32) {
       // Field does not exist or does not index vectors
       return;
     }
@@ -258,7 +260,9 @@ public final void searchNearestVectors(
       String field, byte[] target, KnnCollector knnCollector, Bits acceptDocs) throws IOException {
     ensureOpen();
     FieldInfo fi = getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
+    if (fi == null
+        || fi.getVectorDimension() == 0
+        || fi.getVectorEncoding() != VectorEncoding.BYTE) {
       // Field does not exist or does not index vectors
       return;
     }

lucene/core/src/java/org/apache/lucene/index/FloatVectorValues.java

@@ -54,4 +54,25 @@ public final long cost() {
    * @return the vector value
    */
   public abstract float[] vectorValue() throws IOException;
+
+  /**
+   * Checks the Vector Encoding of a field
+   *
+   * @throws IllegalStateException if {@code field} has vectors, but using a different encoding
+   * @lucene.internal
+   * @lucene.experimental
+   */
+  public static void checkField(LeafReader in, String field) {
+    FieldInfo fi = in.getFieldInfos().fieldInfo(field);
+    if (fi != null && fi.hasVectorValues() && fi.getVectorEncoding() != VectorEncoding.FLOAT32) {
+      throw new IllegalStateException(
+          "Unexpected vector encoding ("
+              + fi.getVectorEncoding()
+              + ") for field "
+              + field
+              + "(expected="
+              + VectorEncoding.FLOAT32
+              + ")");
+    }
+  }
 }

lucene/core/src/java/org/apache/lucene/index/LeafReader.java

@@ -246,11 +246,12 @@ public final PostingsEnum postings(Term term) throws IOException {
   public final TopDocs searchNearestVectors(
       String field, float[] target, int k, Bits acceptDocs, int visitedLimit) throws IOException {
     FieldInfo fi = getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
-      // The field does not exist or does not index vectors
+    FloatVectorValues floatVectorValues = getFloatVectorValues(fi.name);
+    if (floatVectorValues == null) {
+      FloatVectorValues.checkField(this, field);
       return TopDocsCollector.EMPTY_TOPDOCS;
     }
-    k = Math.min(k, getFloatVectorValues(fi.name).size());
+    k = Math.min(k, floatVectorValues.size());
     if (k == 0) {
       return TopDocsCollector.EMPTY_TOPDOCS;
     }
@@ -287,11 +288,12 @@ public final TopDocs searchNearestVectors(
   public final TopDocs searchNearestVectors(
       String field, byte[] target, int k, Bits acceptDocs, int visitedLimit) throws IOException {
     FieldInfo fi = getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
-      // The field does not exist or does not index vectors
+    ByteVectorValues byteVectorValues = getByteVectorValues(fi.name);
+    if (byteVectorValues == null) {
+      ByteVectorValues.checkField(this, field);
       return TopDocsCollector.EMPTY_TOPDOCS;
     }
-    k = Math.min(k, getByteVectorValues(fi.name).size());
+    k = Math.min(k, byteVectorValues.size());
     if (k == 0) {
       return TopDocsCollector.EMPTY_TOPDOCS;
     }

lucene/core/src/java/org/apache/lucene/search/AbstractKnnVectorQuery.java

@@ -187,6 +187,9 @@ protected TopDocs exactSearch(LeafReaderContext context, DocIdSetIterator accept
     }
 
     VectorScorer vectorScorer = createVectorScorer(context, fi);
+    if (vectorScorer == null) {
+      return NO_RESULTS;
+    }
     HitQueue queue = new HitQueue(k, true);
     ScoreDoc topDoc = queue.top();
     int doc;

lucene/core/src/java/org/apache/lucene/search/AbstractVectorSimilarityQuery.java

@@ -105,6 +105,9 @@ public Scorer scorer(LeafReaderContext context) throws IOException {
         if (filterWeight == null) {
           // Return exhaustive results
           TopDocs results = approximateSearch(context, liveDocs, Integer.MAX_VALUE);
+          if (results.scoreDocs.length == 0) {
+            return null;
+          }
           return VectorSimilarityScorer.fromScoreDocs(this, boost, results.scoreDocs);
         }
 
@@ -148,6 +151,8 @@ protected boolean match(int doc) {
               createVectorScorer(context),
               new BitSetIterator(acceptDocs, cardinality),
               resultSimilarity);
+        } else if (results.scoreDocs.length == 0) {
+          return null;
         } else {
           // Return an iterator over the collected results
           return VectorSimilarityScorer.fromScoreDocs(this, boost, results.scoreDocs);

lucene/core/src/java/org/apache/lucene/search/ByteVectorSimilarityValuesSource.java

@@ -39,6 +39,10 @@ public ByteVectorSimilarityValuesSource(byte[] vector, String fieldName) {
   @Override
   public DoubleValues getValues(LeafReaderContext ctx, DoubleValues scores) throws IOException {
     final ByteVectorValues vectorValues = ctx.reader().getByteVectorValues(fieldName);
+    if (vectorValues == null) {
+      ByteVectorValues.checkField(ctx.reader(), fieldName);
+      return DoubleValues.EMPTY;
+    }
     VectorSimilarityFunction function =
         ctx.reader().getFieldInfos().fieldInfo(fieldName).getVectorSimilarityFunction();
     return new DoubleValues() {

lucene/core/src/java/org/apache/lucene/search/FieldExistsQuery.java

@@ -128,12 +128,12 @@ public Query rewrite(IndexSearcher indexSearcher) throws IOException {
           break;
         }
       } else if (fieldInfo.getVectorDimension() != 0) { // the field indexes vectors
-        int numVectors =
+        DocIdSetIterator vectorValues =
             switch (fieldInfo.getVectorEncoding()) {
-              case FLOAT32 -> leaf.getFloatVectorValues(field).size();
-              case BYTE -> leaf.getByteVectorValues(field).size();
+              case FLOAT32 -> leaf.getFloatVectorValues(field);
+              case BYTE -> leaf.getByteVectorValues(field);
             };
-        if (numVectors != leaf.maxDoc()) {
+        if (vectorValues != null && vectorValues.cost() != leaf.maxDoc()) {
           allReadersRewritable = false;
           break;
         }

lucene/core/src/java/org/apache/lucene/search/FloatVectorSimilarityValuesSource.java

@@ -40,6 +40,9 @@ public FloatVectorSimilarityValuesSource(float[] vector, String fieldName) {
   @Override
   public DoubleValues getValues(LeafReaderContext ctx, DoubleValues scores) throws IOException {
     final FloatVectorValues vectorValues = ctx.reader().getFloatVectorValues(fieldName);
+    if (vectorValues == null) {
+      return DoubleValues.EMPTY;
+    }
     VectorSimilarityFunction function =
         ctx.reader().getFieldInfos().fieldInfo(fieldName).getVectorSimilarityFunction();
     return new DoubleValues() {

lucene/core/src/java/org/apache/lucene/search/KnnByteVectorQuery.java

@@ -21,9 +21,9 @@
 import java.util.Objects;
 import org.apache.lucene.codecs.KnnVectorsReader;
 import org.apache.lucene.document.KnnFloatVectorField;
+import org.apache.lucene.index.ByteVectorValues;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.search.knn.KnnCollectorManager;
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.Bits;
@@ -83,13 +83,13 @@ protected TopDocs approximateSearch(
       KnnCollectorManager knnCollectorManager)
       throws IOException {
     KnnCollector knnCollector = knnCollectorManager.newCollector(visitedLimit, context);
-    FieldInfo fi = context.reader().getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
-      // The field does not exist or does not index vectors
-      return TopDocsCollector.EMPTY_TOPDOCS;
+    ByteVectorValues byteVectorValues = context.reader().getByteVectorValues(field);
+    if (byteVectorValues == null) {
+      ByteVectorValues.checkField(context.reader(), field);
+      return NO_RESULTS;
     }
-    if (Math.min(knnCollector.k(), context.reader().getByteVectorValues(fi.name).size()) == 0) {
-      return TopDocsCollector.EMPTY_TOPDOCS;
+    if (Math.min(knnCollector.k(), byteVectorValues.size()) == 0) {
+      return NO_RESULTS;
     }
     context.reader().searchNearestVectors(field, target, knnCollector, acceptDocs);
     TopDocs results = knnCollector.topDocs();
@@ -98,9 +98,6 @@ protected TopDocs approximateSearch(
 
   @Override
   VectorScorer createVectorScorer(LeafReaderContext context, FieldInfo fi) throws IOException {
-    if (fi.getVectorEncoding() != VectorEncoding.BYTE) {
-      return null;
-    }
     return VectorScorer.create(context, fi, target);
   }
 

lucene/core/src/java/org/apache/lucene/search/KnnFloatVectorQuery.java

@@ -22,8 +22,8 @@
 import org.apache.lucene.codecs.KnnVectorsReader;
 import org.apache.lucene.document.KnnFloatVectorField;
 import org.apache.lucene.index.FieldInfo;
+import org.apache.lucene.index.FloatVectorValues;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.search.knn.KnnCollectorManager;
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.Bits;
@@ -84,13 +84,13 @@ protected TopDocs approximateSearch(
       KnnCollectorManager knnCollectorManager)
       throws IOException {
     KnnCollector knnCollector = knnCollectorManager.newCollector(visitedLimit, context);
-    FieldInfo fi = context.reader().getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
-      // The field does not exist or does not index vectors
-      return TopDocsCollector.EMPTY_TOPDOCS;
+    FloatVectorValues floatVectorValues = context.reader().getFloatVectorValues(field);
+    if (floatVectorValues == null) {
+      FloatVectorValues.checkField(context.reader(), field);
+      return NO_RESULTS;
     }
-    if (Math.min(knnCollector.k(), context.reader().getFloatVectorValues(fi.name).size()) == 0) {
-      return TopDocsCollector.EMPTY_TOPDOCS;
+    if (Math.min(knnCollector.k(), floatVectorValues.size()) == 0) {
+      return NO_RESULTS;
     }
     context.reader().searchNearestVectors(field, target, knnCollector, acceptDocs);
     TopDocs results = knnCollector.topDocs();
@@ -99,9 +99,6 @@ protected TopDocs approximateSearch(
 
   @Override
   VectorScorer createVectorScorer(LeafReaderContext context, FieldInfo fi) throws IOException {
-    if (fi.getVectorEncoding() != VectorEncoding.FLOAT32) {
-      return null;
-    }
     return VectorScorer.create(context, fi, target);
   }
 

lucene/core/src/java/org/apache/lucene/search/VectorScorer.java

@@ -41,13 +41,21 @@ abstract class VectorScorer {
   static FloatVectorScorer create(LeafReaderContext context, FieldInfo fi, float[] query)
       throws IOException {
     FloatVectorValues values = context.reader().getFloatVectorValues(fi.name);
+    if (values == null) {
+      FloatVectorValues.checkField(context.reader(), fi.name);
+      return null;
+    }
     final VectorSimilarityFunction similarity = fi.getVectorSimilarityFunction();
     return new FloatVectorScorer(values, query, similarity);
   }
 
   static ByteVectorScorer create(LeafReaderContext context, FieldInfo fi, byte[] query)
       throws IOException {
     ByteVectorValues values = context.reader().getByteVectorValues(fi.name);
+    if (values == null) {
+      ByteVectorValues.checkField(context.reader(), fi.name);
+      return null;
+    }
     VectorSimilarityFunction similarity = fi.getVectorSimilarityFunction();
     return new ByteVectorScorer(values, query, similarity);
   }

lucene/core/src/test/org/apache/lucene/search/TestKnnByteVectorQuery.java

@@ -87,6 +87,21 @@ public void testGetTarget() {
     assertNotSame(queryVectorBytes, q1.getTargetCopy());
   }
 
+  public void testVectorEncodingMismatch() throws IOException {
+    try (Directory indexStore =
+            getIndexStore("field", new float[] {0, 1}, new float[] {1, 2}, new float[] {0, 0});
+        IndexReader reader = DirectoryReader.open(indexStore)) {
+      Query filter = null;
+      if (random().nextBoolean()) {
+        filter = new MatchAllDocsQuery();
+      }
+      AbstractKnnVectorQuery query =
+          new KnnFloatVectorQuery("field", new float[] {0, 1}, 10, filter);
+      IndexSearcher searcher = newSearcher(reader);
+      expectThrows(IllegalStateException.class, () -> searcher.search(query, 10));
+    }
+  }
+
   private static class ThrowingKnnVectorQuery extends KnnByteVectorQuery {
 
     public ThrowingKnnVectorQuery(String field, byte[] target, int k, Query filter) {

lucene/core/src/test/org/apache/lucene/search/TestKnnFloatVectorQuery.java

@@ -79,6 +79,20 @@ public void testToString() throws IOException {
     }
   }
 
+  public void testVectorEncodingMismatch() throws IOException {
+    try (Directory indexStore =
+            getIndexStore("field", new float[] {0, 1}, new float[] {1, 2}, new float[] {0, 0});
+        IndexReader reader = DirectoryReader.open(indexStore)) {
+      Query filter = null;
+      if (random().nextBoolean()) {
+        filter = new MatchAllDocsQuery();
+      }
+      AbstractKnnVectorQuery query = new KnnByteVectorQuery("field", new byte[] {0, 1}, 10, filter);
+      IndexSearcher searcher = newSearcher(reader);
+      expectThrows(IllegalStateException.class, () -> searcher.search(query, 10));
+    }
+  }
+
   public void testGetTarget() {
     float[] queryVector = new float[] {0, 1};
     KnnFloatVectorQuery q1 = new KnnFloatVectorQuery("f1", queryVector, 10);

lucene/join/src/java/org/apache/lucene/search/join/DiversifyingChildrenByteKnnVectorQuery.java

@@ -22,7 +22,6 @@
 import org.apache.lucene.index.ByteVectorValues;
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.index.VectorEncoding;
 import org.apache.lucene.index.VectorSimilarityFunction;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.HitQueue;
@@ -80,21 +79,21 @@ public DiversifyingChildrenByteKnnVectorQuery(
   @Override
   protected TopDocs exactSearch(LeafReaderContext context, DocIdSetIterator acceptIterator)
       throws IOException {
-    FieldInfo fi = context.reader().getFieldInfos().fieldInfo(field);
-    if (fi == null || fi.getVectorDimension() == 0) {
-      // The field does not exist or does not index vectors
+    ByteVectorValues byteVectorValues = context.reader().getByteVectorValues(field);
+    if (byteVectorValues == null) {
+      ByteVectorValues.checkField(context.reader(), field);
       return NO_RESULTS;
     }
-    if (fi.getVectorEncoding() != VectorEncoding.BYTE) {
-      return null;
-    }
+
     BitSet parentBitSet = parentsFilter.getBitSet(context);
     if (parentBitSet == null) {
       return NO_RESULTS;
     }
+
+    FieldInfo fi = context.reader().getFieldInfos().fieldInfo(field);
     ParentBlockJoinByteVectorScorer vectorScorer =
         new ParentBlockJoinByteVectorScorer(
-            context.reader().getByteVectorValues(field),
+            byteVectorValues,
             acceptIterator,
             parentBitSet,
             query,