get_unused_config_keys causes unknown configuration key error for arrays in plugin

[jd-nm26]

Kibana version: 7.6.0

Elasticsearch version: 7.6.0

Server OS version: Debian 10

Browser version: Chrome (N/A, since Kibana doesn't start)

Browser OS version: Windows

Original install method (e.g. download page, yum, from source, etc.): cloned source from v7.6.0 tag on github.

Describe the bug: If you include a plugin parameter in kibana.yml/kibana.dev.yml which is an array, get_unused_config_keys will throw a parameter validation error and Kibana will stop.

Steps to reproduce:

1. Create plugin with a trivial configuration in server/index.ts to allow any type of parameters:

export const config = {
  schema: schema.any()
}

2. Modify kibana.yml or kibana.dev.yml to have an array parameter for your plugin:

my_plugin:
  enabled: true
  other_params:
  - "one"
  - "two"
  - "three"

3. Run in dev mode.

4. Kibana will halt with the following error:

 log   [23:38:59.885] [fatal][root] { Error: Unknown configuration key(s): "my_plugin.other_params". Check for spelling errors and ensure that expected plugins are installed.
    at ensureValidConfiguration (kibana/src/core/server/legacy/config/ensure_valid_configuration.ts:41:11) code: 'InvalidConfig', processExitCode: 64, cause: undefined 

Expected behavior:

Screenshots (if relevant):

Errors in browser console (if relevant): N/A

Provide logs and/or server output (if relevant):

Any additional context:

It appears get_unused_config_keys.ts stores the array keys as:

• my_plugin.other_params.0
• my_plugin.other_params.1
• my_plugin.other_params.2

so that the call to lodash.difference does not correctly validate the existence of the keys.

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[pgayvallet]

Fixed on 7.7 by #56105

[mshustov]

@pgayvallet should we port to 7.6?

[pgayvallet]

7.6: #58998

[pgayvallet]

Closing as resolved on 7.6+

[srinivasuk]

i am installing sense from kibana root folder with below command

.\bin\kibana.bat --install elastic/sense

i get below error.

i am using 'kibana-7.8.0-windows-x86_64'

log [20:13:14.866] [info][plugins-service] Plugin "ingestManager" is disabled.
log [20:13:14.867] [info][plugins-service] Plugin "lists" is disabled.
log [20:13:24.374] [warning][legacy-service] Some installed third party plugin(s) [xpack_main, monitoring, reporting, spaces, security, dashboard_mode, beats_management, maps, task_manager, encryptedSavedObjects, ingestManager, console_legacy, apm_oss, kibana, elasticsearch, newsfeed, region_map, status_page, tile_map, timelion, ui_metric] are using the legacy plugin format and will no longer work in a future Kibana release. Please refer to https://ela.st/kibana-breaking-changes-8-0 for a list of breaking changes and https://ela.st/kibana-platform-migration for documentation on how to migrate legacy plugins.
log [20:13:24.408] [fatal][root] { Error: Unknown configuration key(s): "install". Check for spelling errors and ensure that expected plugins are installed.
at ensureValidConfiguration (C:\Users\Owner\Documents\softroot\kibana-7.8.0-windows-x86_64\src\core\server\legacy\config\ensure_valid_configuration.js:46:11) code: 'InvalidConfig', processExitCode: 64, cause: undefined }

FATAL Error: Unknown configuration key(s): "install". Check for spelling errors and ensure that expected plugins are installed.

[srinivasuk]

.\bin\kibana-plugin.bat install elastic/sense
Attempting to transfer from elastic/sense
Attempting to transfer from https://artifacts.elastic.co/downloads/kibana-plugins/elastic/sense/elastic/sense-7.8.0.zip
Plugin installation was unsuccessful due to error "No valid url specified."

i tried this script as well, which gives different error shown above.