Aggregations: Outdated error message for allowed characters in aggregation names

[walterra]

Elasticsearch version (bin/elasticsearch --version):

Version: 8.0.0-SNAPSHOT, Build: default/tar/f0fac9f/2019-04-14T10:20:15.677116Z, JVM: 12

Plugins installed:

repository-gcs-8.0.0-SNAPSHOT.zip

JVM version (java -version):

java version "1.8.0_181"
Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)

OS version (uname -a if on a Unix-like system):

macOS 10.14.4 (18E226)

Description of the problem including expected versus actual behavior:

The error message for allowed characters in an aggregation name doesn't match the actually allowed characters.

Since the PR #6708 aggregation names "are now able to use any character except [, ], and >". However, the error messages says "Invalid aggregation name [invalid_agg[]]. Aggregation names must be alpha-numeric and can only contain '_' and '-'"

Steps to reproduce:

In Kibana Dev Console the following triggers the error message, note the [ character in the aggregation name.

GET farequote-2019/_search
{
  "query": {
    "match_all": {}
  },
  "aggs": {
    "invalid[": {
      "avg": {
        "field": "responsetime"
      }
    }
  },
  "size": 0
}

To reiterate: Elasticsearch itself works as expected, it's just the error message that's misleading!

[elasticmachine]

Pinging @elastic/es-analytics-geo

[polyfractal]

Closed by #41573. Thanks for the report @walterra!