Inconsistent RPC responses from Infura vs Alchemy websocket provider

[PhilippLgh]

Describe the bug
Calling getLogs() on both providers and Infura seems to return many false 0 event responses.

Reproduction steps
The code is polling because provider.on('block') had noticeable delay and became unstable.

Stripped some code for clarity:

const provider = new ethers.providers.InfuraProvider.getWebSocketProvider(network, key)
const getLogsForBlock = async (blockNumber: number) => {
  let filter = {
    address: null,
    fromBlock: blockNumber,
    toBlock: blockNumber,
    topics: [
      ethers.utils.id("Transfer(address,address,uint256)"),
    ]
  }
  return provider.getLogs(filter)
}
let last_block = undefined
setInterval(async () => {
   const blockNumber = await provider.getBlockNumber()
   if (last_block == blockNumber) return
   last_block = blockNumber
   const logs = await getLogsForBlock(blockNumber)
}, 3*1000)

Environment:
Node.js, Desktop, "ethers": "^5.4.1",

Search Terms
infura invalid logs log data and transfer events

[ricmoo]

That is more to do with the backend than ethers. There is no way for ethers to know, given a result of zero entries, whether it is correct or not.

If you use the most recent version of ethers, the events API (the .on(event, ...)) can better keep you apprised by keeping an internal per-event latest block number seen counter, for which 0-entry logs do not increment that counter.

Does that make sense and will the event API solve your issue?