More info upon logging an exception to enable tracking config error

[jonaslb]

For a Logstash instance with multiple "large" pipelines, I am occasionally seeing the following error:

[2023-04-03T13:21:54,180][WARN ][logstash.filters.mutate  ] Exception caught while applying mutate filter {:exception=>"Cannot cast org.jruby.RubyArray to org.jruby.RubyString"}

Which might be related to a number of ways that the mutate filter could be configured/misconfigured or maybe is buggy. The problem is - the mutate filter is used probably a hundred times across all the pipelines in the instance. And I don't have a lot of information to use for tracking it further down.

So I'd like to request that the mutate filter output some more information upon an exception occuring. Ideally, which operation failed and how was it configured? Otherwise it can be very hard to find the problem.