Plugin policies are not imported on node boot: their keys are "not recognised policy settings"

[ebuildy]

We moved from 3.7 to 3.8.5, and got this error at startup:

"Validation failed\n\n[{<<\"shards-per-node\">>,1}] are not recognised policy settings

Our rabbitmq.definitions.json :

...
"policies": [
    {
      "vhost": "/",
      "name": "esx-shard",
      "pattern": "^esx$",
      "definition": {
        "shards-per-node": 1
      }
    },
...

This was working fine with RabbitMQ 3.7. Plugin is enabled.

[lukebakken]

rabbitmq/rabbitmq-server#2177

[michaelklishin]

Duplicate of rabbitmq/rabbitmq-server#2384.

[michaelklishin]

Another example: rabbitmq/rabbitmq-server#2381, all with the same root cause. Starting with 3.8.4 this has only become more visible (affected custom exchange plugins, for example), otherwise, the problem was not new and affected other plugins in 3.7.

[michaelklishin]

Addressed in rabbitmq/rabbitmq-server#2384 which will ship in 3.8.6. Those on earlier versions can always import definitions after node startup.