Use FieldInfo vector similarity in knn readers (#13237)

Both the KnnWriters & FieldInfo keep track of the vector similarity used by a given field. This commit ensures they are the same and utilizes the FieldInfo one (which, while these are enums, are exactly the same).

lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/lucene90/Lucene90HnswVectorsReader.java

@@ -158,7 +158,7 @@ public final class Lucene90HnswVectorsReader extends KnnVectorsReader {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
 
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -200,9 +200,18 @@ public final class Lucene90HnswVectorsReader extends KnnVectorsReader {
     return VectorSimilarityFunction.values()[similarityFunctionId];
   }
 
-  private FieldEntry readField(DataInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, info.getVectorSimilarityFunction());
   }
 
   @Override

lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/lucene91/Lucene91HnswVectorsReader.java

@@ -150,7 +150,7 @@ public final class Lucene91HnswVectorsReader extends KnnVectorsReader {
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -192,9 +192,18 @@ public final class Lucene91HnswVectorsReader extends KnnVectorsReader {
     return VectorSimilarityFunction.values()[similarityFunctionId];
   }
 
-  private FieldEntry readField(DataInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, info.getVectorSimilarityFunction());
   }
 
   @Override

lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/lucene92/Lucene92HnswVectorsReader.java

@@ -149,7 +149,7 @@ public final class Lucene92HnswVectorsReader extends KnnVectorsReader {
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -191,9 +191,18 @@ public final class Lucene92HnswVectorsReader extends KnnVectorsReader {
     return VectorSimilarityFunction.values()[similarityFunctionId];
   }
 
-  private FieldEntry readField(IndexInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, info.getVectorSimilarityFunction());
   }
 
   @Override

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

@@ -150,7 +150,7 @@ public final class Lucene94HnswVectorsReader extends KnnVectorsReader {
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -208,10 +208,19 @@ public final class Lucene94HnswVectorsReader extends KnnVectorsReader {
     return VectorEncoding.values()[encodingId];
   }
 
-  private FieldEntry readField(IndexInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorEncoding vectorEncoding = readVectorEncoding(input);
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, vectorEncoding, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, vectorEncoding, info.getVectorSimilarityFunction());
   }
 
   @Override

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

@@ -162,7 +162,7 @@ public final class Lucene95HnswVectorsReader extends KnnVectorsReader implements
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -220,10 +220,19 @@ public final class Lucene95HnswVectorsReader extends KnnVectorsReader implements
     return VectorEncoding.values()[encodingId];
   }
 
-  private FieldEntry readField(IndexInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorEncoding vectorEncoding = readVectorEncoding(input);
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, vectorEncoding, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, vectorEncoding, info.getVectorSimilarityFunction());
   }
 
   @Override

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

@@ -143,7 +143,7 @@ public final class Lucene99FlatVectorsReader extends FlatVectorsReader {
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -183,10 +183,19 @@ public final class Lucene99FlatVectorsReader extends FlatVectorsReader {
     }
   }
 
-  private FieldEntry readField(IndexInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorEncoding vectorEncoding = readVectorEncoding(input);
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, vectorEncoding, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, vectorEncoding, info.getVectorSimilarityFunction());
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/codecs/lucene99/Lucene99HnswVectorsReader.java

@@ -153,7 +153,7 @@ public final class Lucene99HnswVectorsReader extends KnnVectorsReader
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -200,10 +200,19 @@ public final class Lucene99HnswVectorsReader extends KnnVectorsReader
     return VectorEncoding.values()[encodingId];
   }
 
-  private FieldEntry readField(IndexInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorEncoding vectorEncoding = readVectorEncoding(input);
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, vectorEncoding, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, vectorEncoding, info.getVectorSimilarityFunction());
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/codecs/lucene99/Lucene99ScalarQuantizedVectorsReader.java

@@ -108,7 +108,7 @@ public final class Lucene99ScalarQuantizedVectorsReader extends FlatVectorsReade
       if (info == null) {
         throw new CorruptIndexException("Invalid field number: " + fieldNumber, meta);
       }
-      FieldEntry fieldEntry = readField(meta);
+      FieldEntry fieldEntry = readField(meta, info);
       validateFieldEntry(info, fieldEntry);
       fields.put(info.name, fieldEntry);
     }
@@ -236,10 +236,19 @@ public final class Lucene99ScalarQuantizedVectorsReader extends FlatVectorsReade
     return size;
   }
 
-  private FieldEntry readField(IndexInput input) throws IOException {
+  private FieldEntry readField(IndexInput input, FieldInfo info) throws IOException {
     VectorEncoding vectorEncoding = readVectorEncoding(input);
     VectorSimilarityFunction similarityFunction = readSimilarityFunction(input);
-    return new FieldEntry(input, vectorEncoding, similarityFunction);
+    if (similarityFunction != info.getVectorSimilarityFunction()) {
+      throw new IllegalStateException(
+          "Inconsistent vector similarity function for field=\""
+              + info.name
+              + "\"; "
+              + similarityFunction
+              + " != "
+              + info.getVectorSimilarityFunction());
+    }
+    return new FieldEntry(input, vectorEncoding, info.getVectorSimilarityFunction());
   }
 
   @Override