JSON RPC method `eth_feeHistory` returns 1 less item in `baseFeePerGas`

[macong-cdc]

System info:

Steps to reproduce:

curl --location --request POST 'https://eth.bd.evmos.org:8545' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_feeHistory",
    "params": [
        4,
        "latest",
        null
    ],
    "id": 0
}'

Expected behavior:
5 items should be in baseFeePerGas in the response as mentioned here.

This includes the next block after the newest of the returned range, because this value can be derived from the newest block.

Actual behavior:
4 items in baseFeePerGas

{"jsonrpc":"2.0","id":0,"result":{"baseFeePerGas":["0x4a817c800","0x4a817c800","0x4a817c800","0x4a817c800"],"gasUsedRatio":[0.016875,0.003654575,0,0.00144495],"oldestBlock":"0x83e77a"}}

Additional info: [Include gist of relevant config, logs, etc.]

[ramacarlucho]

You are missing an optional param, which is required to obtain the reward response.
The query should look like this

curl --location --request POST 'https://eth.bd.evmos.org:8545' --header 'Content-Type: application/json' --data-raw '{
    "jsonrpc": "2.0",
    "method": "eth_feeHistory",
    "params": [
        4,
        "latest",
        [10,90]
    ],
    "id": 0
}'

So the response is

{"jsonrpc":"2.0","id":0,"result":{"baseFeePerGas":["0x4a817c800","0x4a817c800","0x4a817c800","0x4a817c800"],"gasUsedRatio":[0.00137325,0.0065864,0,0.00332595],"oldestBlock":"0x84075f","reward":[["0x59682f00","0x59682f00"],["0x0","0x0"],["0x0","0x0"],["0x0","0x0"]]}}

[macong-cdc]

@ramacarlucho
I am not talking about reward in the response, I am talking about number of items in baseFeePerGas in the response.

As mentioned in the documentation, with block_count input of 4, 5 items are expected in baseFeePerGas.

>>> w3.eth.fee_history(4, 'latest', [10, 90])
AttributeDict({
    'oldestBlock': 3,
    'reward': [[220, 7145389], [1000000, 6000213], [550, 550], [125, 12345678]],
    'baseFeePerGas': [202583058, 177634473, 155594425, 136217133, 119442408],
    'gasUsedRatio': [0.007390479689642084, 0.0036988514889990873, 0.0018512333048507866, 0.00741217041320997]
})

However, for ethermint, with an input of 4, 4 items are returned in baseFeePerGas.