Problem: Complete redelgation amount may be null

[mr-kenikh]

Tendermint Block Results API may return null amount for complete_redelegation event.

Problem with null amount found in block №3366204:

curl -s "https://mainnet.crypto.org:26657/block_results?height=3366204" | jq '.result.end_block_events[] | select(.type=="complete_redelegation") | .attributes[] | select(.key=="YW1vdW50") | .value'
"MTAyOTE4NjAzOGJhc2Vjcm8="
"MTE1MDAwMDAwMDAwMGJhc2Vjcm8="
null
null

[JayT106]

Looks like there is an error happening during the redelegation event,
https://github.com/cosmos/cosmos-sdk/blob/3458f64f0aeb68796e56dd334c04b5e066ebf089/x/staking/keeper/val_state_change.go#L82

possibly due to this error,
https://github.com/cosmos/cosmos-sdk/blob/3458f64f0aeb68796e56dd334c04b5e066ebf089/x/staking/keeper/delegation.go#L886
It is a silent fail.

if that possible for some operation issue to cause this error? Or just error in purpose, meaning no mature term can do redelegation.

[mr-kenikh]

@JayT106

Decoded end block events:

[
  {
    "type": "complete_unbonding",
    "attributes": [
      { "key": "amount", "value": "100000000basecro", "index": true },
      {
        "key": "validator",
        "value": "crocncl1t322hc258gc7dm005xfq0tsjqp9egujuh5tsnu",
        "index": true
      },
      {
        "key": "delegator",
        "value": "cro1t322hc258gc7dm005xfq0tsjqp9eguju5ege3q",
        "index": true
      }
    ]
  },
  {
    "type": "complete_redelegation",
    "attributes": [
      { "key": "amount", "value": "1029186038basecro", "index": true },
      {
        "key": "delegator",
        "value": "cro1pnrv0hnqrd2ht2nect26yq7vpy30wlf3m2jqw0",
        "index": true
      },
      {
        "key": "source_validator",
        "value": "crocncl1t322hc258gc7dm005xfq0tsjqp9egujuh5tsnu",
        "index": true
      },
      {
        "key": "destination_validator",
        "value": "crocncl1n77qdxwpfhg3j7z0tpt9q4uq0cwjne64v84ks2",
        "index": true
      }
    ]
  },
  {
    "type": "complete_redelegation",
    "attributes": [
      { "key": "amount", "value": "1150000000000basecro", "index": true },
      {
        "key": "delegator",
        "value": "cro12xarkpk2f0psk3j6c49ek6p4hcc7kz7wf6qqtn",
        "index": true
      },
      {
        "key": "source_validator",
        "value": "crocncl1t322hc258gc7dm005xfq0tsjqp9egujuh5tsnu",
        "index": true
      },
      {
        "key": "destination_validator",
        "value": "crocncl1j47t9xajph8fxe87mx9n6yjz05u64vr77mxwkd",
        "index": true
      }
    ]
  },
  {
    "type": "complete_redelegation",
    "attributes": [
      { "key": "amount", "value": "", "index": true },
      {
        "key": "delegator",
        "value": "cro12xarkpk2f0psk3j6c49ek6p4hcc7kz7wf6qqtn",
        "index": true
      },
      {
        "key": "source_validator",
        "value": "crocncl1t322hc258gc7dm005xfq0tsjqp9egujuh5tsnu",
        "index": true
      },
      {
        "key": "destination_validator",
        "value": "crocncl1j47t9xajph8fxe87mx9n6yjz05u64vr77mxwkd",
        "index": true
      }
    ]
  },
  {
    "type": "complete_redelegation",
    "attributes": [
      { "key": "amount", "value": "", "index": true },
      {
        "key": "delegator",
        "value": "cro12xarkpk2f0psk3j6c49ek6p4hcc7kz7wf6qqtn",
        "index": true
      },
      {
        "key": "source_validator",
        "value": "crocncl1t322hc258gc7dm005xfq0tsjqp9egujuh5tsnu",
        "index": true
      },
      {
        "key": "destination_validator",
        "value": "crocncl1j47t9xajph8fxe87mx9n6yjz05u64vr77mxwkd",
        "index": true
      }
    ]
  }
]

Target account: cro12xarkpk2f0psk3j6c49ek6p4hcc7kz7wf6qqtn
Target validator: crocncl1t322hc258gc7dm005xfq0tsjqp9egujuh5tsnu

1. Height 2,974,411 (28 Oct 2021 14:40:29 GMT):
   Validator jailed for reason dip below the min self bond and start unbonding

2. 04FB14F9BC5FD6EEF00C585C9AC2FF5BD50E0E1D61C9978EF06CD4950F098CEC:
   Account redelegate 500 CRO from this validator to new one.
   Redelegate completion 28 Oct 2021 14:40:29 GMT + 28 days = 25 Nov 2021 14:40:29 GMT.

3. 5A39418198F01D2CC8AB563E388579A1084C84560C09623E89304A0C284BC9AB:
   Account redelegate 6000 CRO from this validator to new one.
   Redelegate completion 28 Oct 2021 14:40:29 GMT + 28 days = 25 Nov 2021 14:40:29 GMT.

4. 1F675434857E7F027D2A05C8BAB811A3FADD307A5240451812ECFC13245D8A45:
   Account redelegate 5000 CRO from this validator to new one.
   Redelegate completion 28 Oct 2021 14:40:29 GMT + 28 days = 25 Nov 2021 14:40:29 GMT.

Thus, total 11500 CRO for delegatorAddress, valSrcAddr and valDstAddr with same completion time, what has been emitted in one event 1150000000000basecro (index: 2).

And it doesn't look like an error anymore, but the last two events probably shouldn't have emitted?

[JayT106]

I see, thanks for the context.
So the redelegation at index 2 actually combined 3 operations in the end block event. And I agree with you, the last 2 events should be redundant.

It should be the same issue in the SDK
cosmos/cosmos-sdk#10216

The code patch is in the mainline branch (SDK v0.45) but not sure when will be released.