graphql: getBlock return error for notfound hash, but null for notfound number

[jsvisa]

Expected behaviour

Whether the block-hash or block-number should always return an error or null, should be in the same behavior.

Actual behaviour

not found hash

request

{block(hash: "0xc1d1224983a2b43f2ea1b847337eda55e316e94603386e346abe3f6e08121028") { number }}

response

{
  "errors": [
    {
      "message": "header for hash not found",
      "path": [
        "block"
      ]
    }
  ],
  "data": {
    "block": null
  }
}

not found number

request

{block(number: "0x100") { number }}

response

{
  "data": {
    "block": null
  }
}

but the similar request in JSON-RPC all return null

hash not found request

{
  "jsonrpc": "2.0",
  "method": "eth_getBlockByHash",
  "id": 1,
  "params": [
    "0xc1d1224983a2b43f2ea1b847337eda55e316e94603386e346abe3f6e08121028",
    false
  ]
}

number not found request

{
  "jsonrpc": "2.0",
  "method": "eth_getBlockByNumber",
  "id": 1,
  "params": [
    "0x100",
    false
  ]
}

the response

{
  "id": 1,
  "jsonrpc": "2.0",
  "result": null
}

IMO, we should keep the GraphQL' requests in the same behavior as JSON-RPC's, both return null, or at least let the not-found hash also return null.

@s1na @shemnon WDYT