elastic/elasticsearch · error · RuntimeException

Invalid Keyword override Rule:{rule}

Error message

Invalid Keyword override Rule:{rule}

What it means

Error "Invalid Keyword override Rule:{rule}" thrown in elastic/elasticsearch.

Source

Thrown at modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/StemmerOverrideTokenFilterFactory.java:51

            throw new IllegalArgumentException("stemmer override filter requires either `rules` or `rules_path` to be configured");
        }

        StemmerOverrideFilter.Builder builder = new StemmerOverrideFilter.Builder(false);
        parseRules(rules, builder, "=>");
        overrideMap = builder.build();

    }

    @Override
    public TokenStream create(TokenStream tokenStream) {
        return new StemmerOverrideFilter(tokenStream, overrideMap);
    }

    static void parseRules(List<String> rules, StemmerOverrideFilter.Builder builder, String mappingSep) {
        for (String rule : rules) {
            String[] sides = rule.split(mappingSep, -1);
            if (sides.length != 2) {
                throw new RuntimeException("Invalid Keyword override Rule:" + rule);
            }

            String[] keys = sides[0].split(",", -1);
            String override = sides[1].trim();
            if (override.isEmpty() || override.indexOf(',') != -1) {
                throw new RuntimeException("Invalid Keyword override Rule:" + rule);
            }

            for (String key : keys) {
                String trimmedKey = key.trim();
                if (trimmedKey.isEmpty()) {
                    throw new RuntimeException("Invalid Keyword override Rule:" + rule);
                }
                builder.add(trimmedKey, override);
            }
        }
    }

View on GitHub (pinned to db6a809a66)

When it happens

Trigger: Thrown at modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/StemmerOverrideTokenFilterFactory.java:51 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/ccd1183f160d6344. Report an issue: GitHub.