elastic/elasticsearch · error · ParsingException

Unexpected token {token} in [{pipelineAggregatorName}].

Error message

Unexpected token {token} in [{pipelineAggregatorName}].

What it means

Error "Unexpected token {token} in [{pipelineAggregatorName}]." thrown in elastic/elasticsearch.

Source

Thrown at modules/aggregations/src/main/java/org/elasticsearch/aggregations/pipeline/DerivativePipelineAggregationBuilder.java:209

                        "Unknown key for a " + token + " in [" + pipelineAggregatorName + "]: [" + currentFieldName + "]."
                    );
                }
            } else if (token == XContentParser.Token.START_ARRAY) {
                if (BUCKETS_PATH_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
                    List<String> paths = new ArrayList<>();
                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
                        String path = parser.text();
                        paths.add(path);
                    }
                    bucketsPaths = paths.toArray(new String[paths.size()]);
                } else {
                    throw new ParsingException(
                        parser.getTokenLocation(),
                        "Unknown key for a " + token + " in [" + pipelineAggregatorName + "]: [" + currentFieldName + "]."
                    );
                }
            } else {
                throw new ParsingException(
                    parser.getTokenLocation(),
                    "Unexpected token " + token + " in [" + pipelineAggregatorName + "]."
                );
            }
        }

        if (bucketsPaths == null) {
            throw new ParsingException(
                parser.getTokenLocation(),
                "Missing required field ["
                    + BUCKETS_PATH_FIELD.getPreferredName()
                    + "] for derivative aggregation ["
                    + pipelineAggregatorName
                    + "]"
            );
        }

        DerivativePipelineAggregationBuilder factory = new DerivativePipelineAggregationBuilder(pipelineAggregatorName, bucketsPaths[0]);

View on GitHub (pinned to db6a809a66)

When it happens

Trigger: Thrown at modules/aggregations/src/main/java/org/elasticsearch/aggregations/pipeline/DerivativePipelineAggregationBuilder.java:209 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/cf55ab2e9bec8805. Report an issue: GitHub.