elastic/elasticsearch · error · RuntimeException

Invalid Mapping Rule : [{}]

Error message

Invalid Mapping Rule : [{}]

What it means

Error "Invalid Mapping Rule : [{}]" thrown in elastic/elasticsearch.

Source

Thrown at modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/MappingCharFilterFactory.java:58

        normMap = normMapBuilder.build();
    }

    @Override
    public Reader create(Reader tokenStream) {
        return new MappingCharFilter(normMap, tokenStream);
    }

    // source => target
    private static Pattern rulePattern = Pattern.compile("(.*)\\s*=>\\s*(.*)\\s*$");

    /**
     * parses a list of MappingCharFilter style rules into a normalize char map
     */
    private void parseRules(List<String> rules, NormalizeCharMap.Builder map) {
        for (String rule : rules) {
            Matcher m = rulePattern.matcher(rule);
            if (m.find() == false) {
                throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]");
            }
            String lhs = parseString(m.group(1).trim());
            String rhs = parseString(m.group(2).trim());
            if (lhs == null || rhs == null) throw new RuntimeException("Invalid Mapping Rule : [" + rule + "]. Illegal mapping.");
            map.add(lhs, rhs);
        }
    }

    char[] out = new char[256];

    private String parseString(String s) {
        int readPos = 0;
        int len = s.length();
        int writePos = 0;
        while (readPos < len) {
            char c = s.charAt(readPos++);
            if (c == '\\') {
                if (readPos >= len) throw new RuntimeException("Invalid escaped char in [" + s + "]");

View on GitHub (pinned to db6a809a66)

When it happens

Trigger: Thrown at modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/MappingCharFilterFactory.java:58 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/54a89fdc74e7e064. Report an issue: GitHub.