Reward Calc Wart

[dorin100]

info

• https://input-output.atlassian.net/browse/CAD-3349
• Improving UX for delegators edge case - deregister/register from the same SPO at a specific point in time of the Epoch.

I am not sure what we (Node QA team) can test here. Waiting for more details from Vitor.

• Scenario 1

Start with a registered stake credential which is earning rewards.
De-register the stake credential (you'll need to withdraw the rewards in order to do this) before 4k/f-many slots have elapsed in the current epoch (k is the security parameter, f is the active slot coefficient, 4k/f is equal to two days on mainnet).
Re-register the stake credential after 4k/f many slots have elapsed in the epoch.
Check that this stake credential received rewards at the epoch boundary. 

[JaredCorduan]

Note that there are actually two reward warts. Descriptions of both can be found in the Shelley Spec, see section 17.1 and 17.2 (in the appendix). The one in 17.2 is the one that we fixed in Babbage.

The github issue for 17.2 is IntersectMBO/cardano-ledger#2477
The github pull request to fix 17.2 is IntersectMBO/cardano-ledger#2569

To test that 17.2 is indeed fixed in babbage:

• Start with a registered stake credential which is earning rewards.
• De-register the stake credential (you'll need to withdraw the rewards in order to do this) before 4k/f-many slots have elapsed in the current epoch (k is the security parameter, f is the active slot coefficient, 4k/f is equal to two days on mainnet).
• Re-register the stake credential after 4k/f many slots have elapsed in the epoch.
• Check that this stake credential received rewards at the epoch boundary.

[mkoura]

We already have a test that de-register stake address at the beginning of an epoch and re-register the same address close to the end of the same epoch (it says "second half of an epoch" in the comment, but it is last 60 seconds out of 200 secs long epoch). In next epoch it checks that the stake address has NOT received rewards at the epoch boundary.
See https://github.com/input-output-hk/cardano-node-tests/blob/a86518aab2f8f80dd84117d7e3089c4c4a8407b7/cardano_node_tests/tests/test_staking_rewards.py#L1563-L1588

[dorin100]

Awesome! This means this test should automatically fail when moving to Vasil (because rewards will be paid to the stake address).

[mkoura]

I've just spent an hour debugging why the test is failing in Babbage 🤦‍♂️

[mkoura]

Done in #1107

[JaredCorduan]

thank you @mkoura ! 🙌