Resolving PR comments

server/src/main/java/org/elasticsearch/TransportVersions.java

@@ -183,6 +183,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion ESQL_SERIALIZE_BLOCK_TYPE_CODE = def(9_026_0_00);
     public static final TransportVersion ESQL_THREAD_NAME_IN_DRIVER_PROFILE = def(9_027_0_00);
     public static final TransportVersion INFERENCE_CONTEXT = def(9_028_0_00);
+    public static final TransportVersion RANK_DOCS_MIN_SCORE = def(9_029_0_00);
 
     /*
      * STOP! READ THIS FIRST! No, really,

server/src/main/java/org/elasticsearch/index/query/RankDocsQueryBuilder.java

@@ -28,12 +28,17 @@
 public class RankDocsQueryBuilder extends AbstractQueryBuilder<RankDocsQueryBuilder> {
 
     public static final String NAME = "rank_docs_query";
+    public static final float DEFAULT_MIN_SCORE = Float.MIN_VALUE;
 
     private final RankDoc[] rankDocs;
     private final QueryBuilder[] queryBuilders;
     private final boolean onlyRankDocs;
     private final float minScore;
 
+    public RankDocsQueryBuilder(RankDoc[] rankDocs, QueryBuilder[] queryBuilders, boolean onlyRankDocs) {
+        this(rankDocs, queryBuilders, onlyRankDocs, DEFAULT_MIN_SCORE);
+    }
+
     public RankDocsQueryBuilder(RankDoc[] rankDocs, QueryBuilder[] queryBuilders, boolean onlyRankDocs, float minScore) {
         this.rankDocs = rankDocs;
         this.queryBuilders = queryBuilders;
@@ -43,16 +48,23 @@ public RankDocsQueryBuilder(RankDoc[] rankDocs, QueryBuilder[] queryBuilders, bo
 
     public RankDocsQueryBuilder(StreamInput in) throws IOException {
         super(in);
-        this.rankDocs = in.readArray(c -> c.readNamedWriteable(RankDoc.class), RankDoc[]::new);
+        RankDoc[] rankDocs = in.readArray(c -> c.readNamedWriteable(RankDoc.class), RankDoc[]::new);
+        QueryBuilder[] queryBuilders = null;
+        boolean onlyRankDocs = false;
+
         if (in.getTransportVersion().onOrAfter(TransportVersions.V_8_16_0)) {
-            this.queryBuilders = in.readOptionalArray(c -> c.readNamedWriteable(QueryBuilder.class), QueryBuilder[]::new);
-            this.onlyRankDocs = in.readBoolean();
-            this.minScore = in.readFloat();
-        } else {
-            this.queryBuilders = null;
-            this.onlyRankDocs = false;
-            this.minScore = Float.MIN_VALUE;
+            queryBuilders = in.readOptionalArray(c -> c.readNamedWriteable(QueryBuilder.class), QueryBuilder[]::new);
+            onlyRankDocs = in.readBoolean();
         }
+
+        float minScore = in.getTransportVersion().onOrAfter(TransportVersions.RANK_DOCS_MIN_SCORE)
+            ? in.readFloat()
+            : DEFAULT_MIN_SCORE;
+
+        this.rankDocs = rankDocs;
+        this.queryBuilders = queryBuilders;
+        this.onlyRankDocs = onlyRankDocs;
+        this.minScore = minScore;
     }
 
     @Override
@@ -92,7 +104,9 @@ protected void doWriteTo(StreamOutput out) throws IOException {
         if (out.getTransportVersion().onOrAfter(TransportVersions.V_8_16_0)) {
             out.writeOptionalArray(StreamOutput::writeNamedWriteable, queryBuilders);
             out.writeBoolean(onlyRankDocs);
-            out.writeFloat(minScore);
+            if (out.getTransportVersion().onOrAfter(TransportVersions.RANK_DOCS_MIN_SCORE)) {
+                out.writeFloat(minScore);
+            }
         }
     }
 
@@ -151,6 +165,6 @@ protected int doHashCode() {
 
     @Override
     public TransportVersion getMinimalSupportedVersion() {
-        return TransportVersions.V_8_16_0;
+        return TransportVersions.RANK_DOCS_MIN_SCORE;
     }
 }

server/src/main/java/org/elasticsearch/search/retriever/rankdoc/RankDocsQuery.java

@@ -49,14 +49,16 @@ public static class TopQuery extends Query {
         private final String[] queryNames;
         private final int[] segmentStarts;
         private final Object contextIdentity;
+        private final float minScore;
 
-        TopQuery(RankDoc[] docs, Query[] sources, String[] queryNames, int[] segmentStarts, Object contextIdentity) {
+        TopQuery(RankDoc[] docs, Query[] sources, String[] queryNames, int[] segmentStarts, Object contextIdentity, float minScore) {
             assert sources.length == queryNames.length;
             this.docs = docs;
             this.sources = sources;
             this.queryNames = queryNames;
             this.segmentStarts = segmentStarts;
             this.contextIdentity = contextIdentity;
+            this.minScore = minScore;
             for (RankDoc doc : docs) {
                 if (false == doc.score >= 0) {
                     throw new IllegalArgumentException("RankDoc scores must be positive values. Missing a normalization step?");
@@ -76,7 +78,7 @@ public Query rewrite(IndexSearcher searcher) throws IOException {
                 changed |= newSources[i] != sources[i];
             }
             if (changed) {
-                return new TopQuery(docs, newSources, queryNames, segmentStarts, contextIdentity);
+                return new TopQuery(docs, newSources, queryNames, segmentStarts, contextIdentity, minScore);
             }
             return this;
         }
@@ -165,7 +167,7 @@ public float getMaxScore(int docId) {
 
                         @Override
                         public float score() throws IOException {
-                            return Math.max(docs[upTo].score, Float.MIN_VALUE);
+                            return Math.max(docs[upTo].score, minScore);
                         }
 
                         @Override
@@ -254,7 +256,7 @@ public RankDocsQuery(
         this.docs = rankDocs.clone();
         // sort rank docs by doc id
         Arrays.sort(docs, Comparator.comparingInt(a -> a.doc));
-        this.topQuery = new TopQuery(docs, sources, queryNames, findSegmentStarts(reader, docs), reader.getContext().id());
+        this.topQuery = new TopQuery(docs, sources, queryNames, findSegmentStarts(reader, docs), reader.getContext().id(), minScore);
         if (sources.length > 0 && false == onlyRankDocs) {
             var bq = new BooleanQuery.Builder();
             for (var source : sources) {
@@ -268,12 +270,12 @@ public RankDocsQuery(
         this.minScore = minScore;
     }
 
-    private RankDocsQuery(RankDoc[] docs, Query topQuery, Query tailQuery, boolean onlyRankDocs) {
+    private RankDocsQuery(RankDoc[] docs, Query topQuery, Query tailQuery, boolean onlyRankDocs, float minScore) {
         this.docs = docs;
         this.topQuery = topQuery;
         this.tailQuery = tailQuery;
         this.onlyRankDocs = onlyRankDocs;
-        this.minScore = Float.MIN_VALUE;
+        this.minScore = minScore;
     }
 
     private static int binarySearch(RankDoc[] docs, int fromIndex, int toIndex, int key) {
@@ -317,7 +319,7 @@ public Query rewrite(IndexSearcher searcher) throws IOException {
         if (tailRewrite != tailQuery) {
             hasChanged = true;
         }
-        return hasChanged ? new RankDocsQuery(docs, topRewrite, tailRewrite, onlyRankDocs) : this;
+        return hasChanged ? new RankDocsQuery(docs, topRewrite, tailRewrite, onlyRankDocs, minScore) : this;
     }
 
     @Override