Forbid negative weight in Function Score Query (#33390)

This change forbids negative `weight` in Function Score query. Negative scores are forbidden in Lucene 8.
elastic · Sep 12, 2018 · c92ec1c · c92ec1c
1 parent 4561c5e
commit c92ec1c
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/server/src/main/java/org/elasticsearch/index/query/functionscore/ScoreFunctionBuilder.java b/server/src/main/java/org/elasticsearch/index/query/functionscore/ScoreFunctionBuilder.java
@@ -24,7 +24,6 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.lucene.search.function.ScoreFunction;
 import org.elasticsearch.common.lucene.search.function.WeightFactorFunction;
-import org.elasticsearch.common.xcontent.ToXContent.Params;
 import org.elasticsearch.common.xcontent.ToXContentFragment;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.index.query.QueryShardContext;
@@ -46,7 +45,7 @@ public ScoreFunctionBuilder() {
      * Read from a stream.
      */
     public ScoreFunctionBuilder(StreamInput in) throws IOException {
-        weight = in.readOptionalFloat();
+        weight = checkWeight(in.readOptionalFloat());
     }
 
     @Override
@@ -70,10 +69,17 @@ public final void writeTo(StreamOutput out) throws IOException {
      */
     @SuppressWarnings("unchecked")
     public final FB setWeight(float weight) {
-        this.weight = weight;
+        this.weight = checkWeight(weight);
         return (FB) this;
     }
 
+    private Float checkWeight(Float weight) {
+        if (weight != null && Float.compare(weight, 0) < 0) {
+            throw new IllegalArgumentException("[weight] cannot be negative for a filtering function");
+        }
+        return weight;
+    }
+
     /**
      * The weight applied to the function before combining.
      */

diff --git a/...test/java/org/elasticsearch/index/query/functionscore/FunctionScoreQueryBuilderTests.java b/...test/java/org/elasticsearch/index/query/functionscore/FunctionScoreQueryBuilderTests.java
@@ -20,6 +20,7 @@
 package org.elasticsearch.index.query.functionscore;
 
 import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
@@ -272,6 +273,8 @@ public void testIllegalArguments() {
         FunctionScoreQueryBuilder builder = new FunctionScoreQueryBuilder(matchAllQuery());
         expectThrows(IllegalArgumentException.class, () -> builder.scoreMode(null));
         expectThrows(IllegalArgumentException.class, () -> builder.boostMode(null));
+        expectThrows(IllegalArgumentException.class,
+                () -> new FunctionScoreQueryBuilder.FilterFunctionBuilder(new WeightBuilder().setWeight(-1 * randomFloat())));
     }
 
     public void testParseFunctionsArray() throws IOException {