elastic/elasticsearch · error · IllegalArgumentException

[format] must not be null: [{name}]

Error message

[format] must not be null: [{name}]

What it means

Error "[format] must not be null: [{name}]" thrown in elastic/elasticsearch.

Source

Thrown at modules/aggregations/src/main/java/org/elasticsearch/aggregations/pipeline/DerivativePipelineAggregationBuilder.java:78

            gapPolicy = GapPolicy.readFrom(in);
        }
        units = in.readOptionalString();
    }

    @Override
    protected void doWriteTo(StreamOutput out) throws IOException {
        out.writeOptionalString(format);
        boolean hasGapPolicy = gapPolicy != null;
        out.writeBoolean(hasGapPolicy);
        if (hasGapPolicy) {
            gapPolicy.writeTo(out);
        }
        out.writeOptionalString(units);
    }

    public DerivativePipelineAggregationBuilder format(String format) {
        if (format == null) {
            throw new IllegalArgumentException("[format] must not be null: [" + name + "]");
        }
        this.format = format;
        return this;
    }

    public String format() {
        return format;
    }

    public DerivativePipelineAggregationBuilder gapPolicy(GapPolicy gapPolicy) {
        if (gapPolicy == null) {
            throw new IllegalArgumentException("[gapPolicy] must not be null: [" + name + "]");
        }
        this.gapPolicy = gapPolicy;
        return this;
    }

    public GapPolicy gapPolicy() {

View on GitHub (pinned to db6a809a66)

When it happens

Trigger: Thrown at modules/aggregations/src/main/java/org/elasticsearch/aggregations/pipeline/DerivativePipelineAggregationBuilder.java:78 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/b56ccc9a3d45b087. Report an issue: GitHub.