elastic/elasticsearch · error · IllegalArgumentException

Member variable [{}] does not exist for date field [{}].

Error message

Member variable [{}] does not exist for date field [{}].

What it means

Thrown by DateField.getVariable (lang-expression script engine) when an expression references an unsupported member VARIABLE on a date field. For date fields the only valid variables are 'value', 'empty', and 'length'. Any other variable name in doc['<dateField>'].<var> reaches the default branch.

Source

Thrown at modules/lang-expression/src/main/java/org/elasticsearch/script/expression/DateField.java:53

    static final String AVERAGE_METHOD = "avg";
    static final String MEDIAN_METHOD = "median";
    static final String SUM_METHOD = "sum";
    static final String COUNT_METHOD = "count";

    // date-specific
    static final String GET_YEAR_METHOD = "getYear";
    static final String GET_MONTH_METHOD = "getMonth";
    static final String GET_DAY_OF_MONTH_METHOD = "getDayOfMonth";
    static final String GET_HOUR_OF_DAY_METHOD = "getHourOfDay";
    static final String GET_MINUTES_METHOD = "getMinutes";
    static final String GET_SECONDS_METHOD = "getSeconds";

    static DoubleValuesSource getVariable(IndexFieldData<?> fieldData, String fieldName, String variable) {
        return switch (variable) {
            case VALUE_VARIABLE -> new FieldDataValueSource(fieldData, MultiValueMode.MIN);
            case EMPTY_VARIABLE -> new EmptyMemberValueSource(fieldData);
            case LENGTH_VARIABLE -> new CountMethodValueSource(fieldData);
            default -> throw new IllegalArgumentException(
                "Member variable [" + variable + "] does not exist for date field [" + fieldName + "]."
            );
        };
    }

    static DoubleValuesSource getMethod(IndexFieldData<?> fieldData, String fieldName, String method) {
        return switch (method) {
            case GETVALUE_METHOD -> new FieldDataValueSource(fieldData, MultiValueMode.MIN);
            case ISEMPTY_METHOD -> new EmptyMemberValueSource(fieldData);
            case SIZE_METHOD -> new CountMethodValueSource(fieldData);
            case MINIMUM_METHOD -> new FieldDataValueSource(fieldData, MultiValueMode.MIN);
            case MAXIMUM_METHOD -> new FieldDataValueSource(fieldData, MultiValueMode.MAX);
            case AVERAGE_METHOD -> new FieldDataValueSource(fieldData, MultiValueMode.AVG);
            case MEDIAN_METHOD -> new FieldDataValueSource(fieldData, MultiValueMode.MEDIAN);
            case SUM_METHOD -> new FieldDataValueSource(fieldData, MultiValueMode.SUM);
            case COUNT_METHOD -> new CountMethodValueSource(fieldData);
            case GET_YEAR_METHOD -> new DateMethodValueSource(fieldData, MultiValueMode.MIN, method, Calendar.YEAR);
            case GET_MONTH_METHOD -> new DateMethodValueSource(fieldData, MultiValueMode.MIN, method, Calendar.MONTH);

View on GitHub (pinned to db6a809a66)

Solutions

1. Use a supported variable: doc['timestamp'].value, doc['timestamp'].empty, or doc['timestamp'].length.
2. For date components, use the date object: doc['timestamp'].date.year (variable) or doc['timestamp'].date.getYear (method).
3. Switch to a supported method on the field: doc['timestamp'].getYear, .getMonth, etc.

Example fix

// before (expression script)
doc['timestamp'].year

// after
doc['timestamp'].date.year   // or doc['timestamp'].getYear

// Validate expression variable before using it on a date field
Set<String> OK = Set.of("value", "empty", "length");
if (!OK.contains(variable)) {
    throw new IllegalArgumentException("Unsupported date field variable: " + variable + "; use .date.<var> for components");
}

When it happens

Trigger: Using an expression script (lang: expression) like doc['timestamp'].year or doc['timestamp'].foo where 'timestamp' is a date field. Date FIELD variables are limited to value/empty/length; rich date accessors live on the date OBJECT (doc['timestamp'].date.<var>, see DateObject).

Common situations: Confusing date-field variables with date-object variables; copying a painless-style accessor into an expression script; assuming getYear-style accessors work as variables rather than methods.

Related errors

• Member method [{}] does not exist for date field [{}].
• Member variable [{}] does not exist for date object on field
• Member method [{}] does not exist for date object on field [
• Error evaluating {}
• Can't advance to doc using {}

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/5853f3717857b226. Report an issue: GitHub.