debug_traceBlockByNumber error "invalid signer list on checkpoint block"

[s1na]

We've been running debug_traceBlockByNumber on a long range of blocks together with https://github.com/XinFinOrg/XDPoSChain/pull/683. I really doubt this error should stem from the PR. Seems like a more general issue in traceBlock.

An error occurred in block 80223300:invalid signer list on checkpoint block
Searching for block 80224200 , 0 contracts match the criteria
An error occurred in block 80224200:invalid signer list on checkpoint block
Searching for block 80225100 , 0 contracts match the criteria
An error occurred in block 80225100:invalid signer list on checkpoint block
Searching for block 80226000 , 0 contracts match the criteria
An error occurred in block 80226000:invalid signer list on checkpoint block
Searching for block 80226900 , 0 contracts match the criteria
An error occurred in block 80226900:invalid signer list on checkpoint block
Searching for block 80227800 , 0 contracts match the criteria
An error occurred in block 80227800:invalid signer list on checkpoint block
Searching for block 80228700 , 0 contracts match the criteria
An error occurred in block 80228700:invalid signer list on checkpoint block
Searching for block 80229600 , 0 contracts match the criteria
An error occurred in block 80229600:invalid signer list on checkpoint block
Searching for block 80230500 , 0 contracts match the criteria
An error occurred in block 80230500:invalid signer list on checkpoint block
Searching for block 80231400 , 0 contracts match the criteria
An error occurred in block 80231400:invalid signer list on checkpoint block
Searching for block 80232300 , 0 contracts match the criteria
An error occurred in block 80232300:invalid signer list on checkpoint block
Searching for block 80233200 , 0 contracts match the criteria
An error occurred in block 80233200:invalid signer list on checkpoint block
Searching for block 80234100 , 0 contracts match the criteria
An error occurred in block 80234100:invalid signer list on checkpoint block
Searching for block 80235000 , 0 contracts match the criteria
An error occurred in block 80235000:invalid signer list on checkpoint block
Searching for block 80235900 , 0 contracts match the criteria[A
An error occurred in block 80235900:invalid signer list on checkpoint block
Searching for block 80236800 , 0 contracts match the criteria
An error occurred in block 80236800:invalid signer list on checkpoint block

You can reproduce it by:

root@vmi1959243:~/Scripts/src# curl -X POST -H "Content-Type: application/json" --data '{"method":"debug_traceBlockByNumber","params":["0x4c81c44"],"id":1,"jsonrpc":"2.0"}' 0.0.0.0:8989
{"jsonrpc":"2.0","id":1,"error":{"code":-32000,"message":"invalid signer list on checkpoint block"}}

[JukLee0ira]

I'll check the code and try to find the cause