Unexpected `Unsupported endpoint version` on REST API

[yorickdowne]

Description

When sending an exit message for a validator that has already exited to eth/v1/beacon/pool/voluntary_exits, Lighthouse v4.3.0 returns:

{
  "code": 400,
  "message": "BAD_REQUEST: Unsupported endpoint version: v1",
  "stacktraces": []
}

The same call for a validator that hasn't been exited yet, succeeds.

Version

v4.3.0

Expected Behaviour

Send a message that is more descriptive of the actual error encountered

Additional info

I have seen user reports of other REST calls that also fail with Unsupported endpoint version where a different message may be more appropriate.

[michaelsproul]

This was long-standing bug which we finally fixed in #4595. Almost all occurences of it should be gone now, including from the POST endpoint for voluntary exits.

The original bug is here: #3404

The fix will be in our next release

[yorickdowne]

Excellent thank you!

[chaseadam]

I received this when I attempted to POST incorrect "Content-Type" to /eth/v1/beacon/pool/bls_to_execution_changes and also when attempting to incorrectly post to /eth/v1/beacon/pool/bls_to_execution_change (no s on the end).

What ended up working for me:
curl -vvv --json @<JSON file> http://<BN HTTP>/eth/v1/beacon/pool/bls_to_execution_changes