[Grok Debugger] field names with special characters not possible

[elasticmachine]

Original comment by @LucaWintergerst:

Kibana version: 6.0.0

Elasticsearch version: 6.0.0

Description of the problem including expected versus actual behavior:

Logstash allows special characters in field names to create the hidden EMAIL REDACTED fields in logstash. These are used to store data which is not sent to the outputs by default.
When debugging grok expressions containing this syntax, the debugger either throws an error or fails silently. (error in Chrome on Mac, silent fail on Deb9 with Chromium). While not critical for the overall functionality, it is annoying that these field names have to be substituted before and after debugging.

Steps to reproduce:

1. enter any data to match
2. attempt to match nested special field: EMAIL REDACTED

Errors in browser console (if relevant):
GrokDebugger: Provided Grok patterns do not match data in the input

[elasticmachine]

Original comment by @talevy:

thanks for sharing this. I looked into this in the past but failed to finish up the job. Here is the issue for this in es: elastic/elasticsearch#21745

[jloleysens]

Hi @LucaWintergerst ! I tested this on current master and was not able to reproduce the error described.

I am going to close this issue for now, let me know if you are still running into this by re-opening with details on how to reproduce. Thanks!