elastic/elasticsearch · error · GeneralScriptException

Error evaluating {}

Error message

Error evaluating {}

What it means

Thrown inside ExpressionScoreScript.execute(ExplanationHolder) when values.doubleValue() raises any Exception, wrapped in GeneralScriptException with the expression source text. This fires during function_score or script_score evaluation when the computed score cannot be retrieved for the current document.

Source

Thrown at modules/lang-expression/src/main/java/org/elasticsearch/script/expression/ExpressionScoreScript.java:81

            // Fake the scorer until setScorer is called.
            DoubleValues values = source.getValues(leaf, new DoubleValues() {
                @Override
                public double doubleValue() throws IOException {
                    return get_score();
                }

                @Override
                public boolean advanceExact(int doc) throws IOException {
                    return true;
                }
            });

            @Override
            public double execute(ExplanationHolder explanation) {
                try {
                    return values.doubleValue();
                } catch (Exception exception) {
                    throw new GeneralScriptException("Error evaluating " + exprScript, exception);
                }
            }

            @Override
            public void setDocument(int d) {
                try {
                    values.advanceExact(d);
                } catch (IOException e) {
                    throw new IllegalStateException("Can't advance to doc using " + exprScript, e);
                }
            }
        };
    }

}

View on GitHub (pinned to db6a809a66)

Solutions

1. If the expression uses _score, ensure the surrounding query is a score-producing query (not a filter context).
2. Verify all doc['field'] references point to fields with doc_values enabled and present in the mapping.
3. Simplify the expression to isolate which variable causes the failure: start with doc['field'].value, then add complexity.
4. Provide a fallback by wrapping the script in a condition or using the script's params to supply defaults for missing values.

Example fix

// before: expression references field that may be missing
GET my-index/_search
{
  "query": {
    "function_score": {
      "script_score": { "script": { "lang": "expression", "source": "doc['rating'].value" } }
    }
  }
}
// after: ensure field has doc_values and provide default via params
GET my-index/_search
{
  "query": {
    "function_score": {
      "script_score": {
        "script": {
          "lang": "expression",
          "source": "doc['rating'].value",
          "params": {}
        }
      }
    }
  }
}

// Before using a script_score query, verify the expression's fields exist and have data
GET my-index/_search
{ "size": 0, "aggs": { "check": { "stats": { "field": "rating" } } } }
// If 'rating' returns no stats, the expression will fail at runtime

try {
    double score = scoreScript.execute(explanationHolder);
} catch (GeneralScriptException e) {
    logger.warn("Expression score evaluation failed: {}", e.getMessage(), e);
    // Return a neutral score or rethrow depending on query requirements
    return 1.0f;
}

When it happens

Trigger: Using a function_score or script_score query with "lang":"expression" and doubleValue() fails — e.g., the backing DoubleValues (often _score or a doc value) is unavailable or raises an error during score computation.

Common situations: Expression references _score when the query does not actually produce scores; doc_values field is missing for some documents; expression causes arithmetic overflow or references an unloaded field data cache.

Related errors

• Error evaluating {}
• Can't advance to doc using {}
• Error evaluating {}
• Can't advance to doc using {}
• Can't advance to doc using {}

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/d092b7e8a4c7c405. Report an issue: GitHub.