elastic/elasticsearch · error · IllegalArgumentException

Multiplexing filter [{}] refers to undefined tokenfilter [{}

Error message

Multiplexing filter [{}] refers to undefined tokenfilter [{}]

What it means

Error "Multiplexing filter [{}] refers to undefined tokenfilter [{}]" thrown in elastic/elasticsearch.

Source

Thrown at modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/MultiplexerTokenFilterFactory.java:140

            @Override
            public String name() {
                return name;
            }

            @Override
            public TokenStream create(TokenStream tokenStream) {
                for (TokenFilterFactory tff : filters) {
                    tokenStream = tff.create(tokenStream);
                }
                return tokenStream;
            }
        };
    }

    private TokenFilterFactory resolveFilterFactory(Function<String, TokenFilterFactory> factories, String name) {
        TokenFilterFactory factory = factories.apply(name);
        if (factory == null) {
            throw new IllegalArgumentException("Multiplexing filter [" + name() + "] refers to undefined tokenfilter [" + name + "]");
        } else {
            return factory;
        }
    }

    private static final class MultiplexTokenFilter extends TokenFilter {

        private final TokenStream source;
        private final int filterCount;

        private int selector;

        /**
         * Creates a MultiplexTokenFilter on the given input with a set of filters
         */
        MultiplexTokenFilter(TokenStream input, List<Function<TokenStream, TokenStream>> filters) {
            super(input);
            TokenStream sourceFilter = new MultiplexerFilter(input);

View on GitHub (pinned to db6a809a66)

When it happens

Trigger: Thrown at modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/MultiplexerTokenFilterFactory.java:140 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/702beeeb1e4832e8. Report an issue: GitHub.