AppendProcessor 'value' should accept a scalar or array

[andrewkroh]

🐛 Wrong type

The AppendProcessor should accept either a single value or an array of values for its value field. But the specification only allows for an array of values.

elasticsearch-specification/specification/ingest/_types/Processors.ts

Line 282 in 24afbdf

value: UserDefinedValue[]

The append processor docs say:

Accepts a single value or an array of values.

The Elasticsearch processor accepts a java Object, and this is the location where it gets used:

https://github.com/elastic/elasticsearch/blob/2292406f66ee1b3bd133bb95aaf2c4d3d27d7265/server/src/main/java/org/elasticsearch/ingest/IngestDocument.java#L672-L676

For example, this Fleet integration pipeline would not match the current spec.

Definition

If possible provide a snippet with the fix.

- value: UserDefinedValue[] 
+ value: UserDefinedValue[] | UserDefinedValue

[andrewkroh]

Fixed by #2854.