replayPastAndFutureBlocksFlowable does not emit current block if startBlock is "latest"

[azige]

replayPastAndFutureBlocksFlowable does not emit current block if startBlock is "latest"

I'm developing a module in a spring webflux project for block number and hash tracking. I want to emit a event of "current block" at application starting and then emit any new blocks. I found replayPastAndFutureBlocksFlowable and try to make use of it.

I tried to build a flowable like this

web3j.replayPastAndFutureBlocksFlowable(DefaultBlockParameterName.LATEST, false)

But this flowable doesn't emit the latest block ("current block") and only emits newly mined blocks, i.e. if current block number is 125, it emits a block from 126.

Then I tried this

Mono.from(web3j.ethBlockNumber().flowable())
    .flatMapMany {
        web3j.replayPastAndFutureBlocksFlowable(
            DefaultBlockParameter.valueOf(it.blockNumber),
            false
        )
    }

This does not work too. And then this

Mono.from(web3j.ethBlockNumber().flowable())
    .flatMapMany {
        web3j.replayPastAndFutureBlocksFlowable(
            DefaultBlockParameter.valueOf(it.blockNumber - BigInteger.ONE),
            false
        )
    }

This time the flow does emit the latest block and one block before it, i.e. if current block number is 125, it emits 124 and 125 and any later blocks.

I investigate the source code and found https://github.com/web3j/web3j/blob/bb276caf4b63508fef66149d8d0bafc510669628/core/src/main/java/org/web3j/protocol/rx/JsonRpc2_0Rx.java#L194

It means web3j.replayPastAndFutureBlocksFlowable(DefaultBlockParameterName.LATEST, false) is effectively equal to web3j.blockFlowable(false). Is it intended behavior? Or the condition above should be startBlockNumber.compareTo(latestBlockNumber) > 0?

[pentiak]

I think I encountered the same issue. Any plans to have it fixed?