script_score comparison operators failing on 1.4.1

[jsnod]

Hi,

We recently upgraded from v1.3.2 to v1.4.1. A function_score query using script_score is now failing when using > or < operators on the _score. Our script worked fine in 1.3, but after upgrading to 1.4.1 it fails with the following GroovyRuntimeException:

QueryPhaseExecutionException[[script_score_test][3]: query[filtered(function score (ConstantScore(:),function=script[if (_score > max_val) {0.0} else {_score}], params [{max_val=10.0}]))->cache(_type:my_type)],from[0],size[10]: Query Failed [Failed to execute main query]]; nested: GroovyScriptExecutionException[GroovyRuntimeException[Cannot compare org.elasticsearch.script.ScoreAccessor with value 'org.elasticsearch.script.ScoreAccessor@2553f628' and java.lang.Double with value '10.0']];

Not sure if this is a bug in Groovy or we need to change our script syntax to be compatible. Here are some sample steps to reproduce.

DELETE /script_score_test
PUT /script_score_test/my_type/1
{
    "prop1" : 5.3,
    "prop2" : 6.7
}
PUT /script_score_test/my_type/2
{
    "prop1" : 9.6,
    "prop2" : 15.4
}

The following query fails:

GET /script_score_test/my_type/_search
{
  "query": {
    "function_score": {
      "boost_mode": "replace",
      "script_score": {
        "script": "if (_score < max_val) {0.0} else {_score}",
        "params": {
          "max_val": 10
        }
      }
    }
  }
}

Interestingly, the query works when using the == operator. :

GET /script_score_test/my_type/_search
{
  "query": {
    "function_score": {
      "boost_mode": "replace",
      "script_score": {
        "script": "if (_score == max_val) {0.0} else {_score}",
        "params": {
          "max_val": 10
        }
      }
    }
  }
}

Also, using compareTo seems to work:

GET /script_score_test/my_type/_search
{
  "query": {
    "function_score": {
      "boost_mode": "replace",
      "script_score": {
        "script": "if (_score.compareTo(max_val) < 0) {0.0} else {_score}",
        "params": {
          "max_val": 10
        }
      }
    }
  }
}

We're OK with updating our scripts to use compareTo to make everything work, but we'd prefer to use the simpler < > syntax. I wanted to file this issue in case it's an actual bug or in case someone else comes across it.

[rjernst]

@dakrone do you have any ideas? I made the script accessor a Number, and it seemed like that should work the same as the boxed types, but it doesn't appear to in this case? I also am skeptical that == is not just comparing reference equality of the boxed value with the script accessor?

[dakrone]

@rjernst the ScriptAccessor needs to implement Comparable in order to work with < and >, this seems to fix it for me:

diff --git a/src/main/java/org/elasticsearch/script/ScoreAccessor.java b/src/main/java/org/elasticsearch/script/ScoreAccessor.java
index 93536e5..e8c4333 100644
--- a/src/main/java/org/elasticsearch/script/ScoreAccessor.java
+++ b/src/main/java/org/elasticsearch/script/ScoreAccessor.java
@@ -30,7 +30,7 @@ import java.io.IOException;
  * The provided {@link DocLookup} is used to retrieve the score
  * for the current document.
  */
-public final class ScoreAccessor extends Number {
+public final class ScoreAccessor extends Number implements Comparable<Number> {

     Scorer scorer;

@@ -65,4 +65,9 @@ public final class ScoreAccessor extends Number {
     public double doubleValue() {
         return score();
     }
+
+    @Override
+    public int compareTo(Number o) {
+        return Float.compare(this.score(), o.floatValue());
+    }
 }

And then the _score < max_val worked.

[s1monw]

+1 for @dakrone fix