Remove incorrect/expensive use of ServiceLoader for choosing random f…

…ormat (#13428)

# Conflicts:
#	lucene/test-framework/src/java/org/apache/lucene/tests/util/LuceneTestCase.java

lucene/core/src/java/org/apache/lucene/codecs/KnnVectorsFormat.java

@@ -18,6 +18,7 @@
 package org.apache.lucene.codecs;
 
 import java.io.IOException;
+import java.util.Set;
 import org.apache.lucene.index.ByteVectorValues;
 import org.apache.lucene.index.FloatVectorValues;
 import org.apache.lucene.index.SegmentReadState;
@@ -86,6 +87,11 @@ public static KnnVectorsFormat forName(String name) {
  return Holder.getLoader().lookup(name);
  }
 
+ /** returns a list of all available format names */
+ public static Set<String> availableKnnVectorsFormats() {
+ return Holder.getLoader().availableServices();
+ }
+
  /** Returns a {@link KnnVectorsWriter} to write the vectors to the index. */
  public abstract KnnVectorsWriter fieldsWriter(SegmentWriteState state) throws IOException;
 

lucene/test-framework/src/java/org/apache/lucene/tests/util/LuceneTestCase.java

@@ -3281,4 +3281,22 @@ public static BytesRef newBytesRef(byte[] bytesIn, int offset, int length) {
 
  return it;
  }
+
+ private static boolean supportsVectorEncoding(
+ KnnVectorsFormat format, VectorEncoding vectorEncoding) {
+ if (format instanceof HnswBitVectorsFormat) {
+ // special case, this only supports BYTE
+ return vectorEncoding == VectorEncoding.BYTE;
+ }
+ return true;
+ }
+
+ protected static KnnVectorsFormat randomVectorFormat(VectorEncoding vectorEncoding) {
+ List<KnnVectorsFormat> availableFormats =
+ KnnVectorsFormat.availableKnnVectorsFormats().stream()
+ .map(KnnVectorsFormat::forName)
+ .filter(format -> supportsVectorEncoding(format, vectorEncoding))
+ .toList();
+ return RandomPicks.randomFrom(random(), availableFormats);
+ }
 }