StoredBlock.serializeCompact() trims AuxPoW

[oscarguindzberg]

See https://github.com/bitcoinj/bitcoinj/blob/v0.14.2/core/src/main/java/org/bitcoinj/core/StoredBlock.java#L131 This method is invoked by bitcoinj's blockstores (eg LevelDBBlockStore) before storing a block, so AuxPow is missing from blocks stored in blockstores.

[rnicoll]

I think this was vaguely intentional, in that you only need the 80 bytes to make the blockchain and it's therefore enough for SPV clients.

Do you have a specific use-case this needs changing for, or is this a documentation issue (possibly I need a parallel option for retaining AuxPoW?)

[oscarguindzberg]

I see your point of SPV clients.

I have an use case. We have an agent that sends doge block headers to ethereum. That is part of the Doge-Eth bridge. We don't send doge headers as we receive them. We store them and send them later on. My agent should send the full header but is just sending the first 80 bytes.

[rnicoll]

Okay, I'll work with bitcoinj to get some extension hooks in so it can handle non-80-byte headers. Meanwhile if you subclass StoredBlock could that let you make progress?

[oscarguindzberg]

Thanks! We are writing a custom BlockStore as a workaround, so we are fine.

On Mon, Jan 29, 2018 at 5:22 AM, Ross Nicoll [email protected] wrote:

Okay, I'll work with bitcoinj to get some extension hooks in so it can handle non-80-byte headers. Meanwhile if you subclass StoredBlock could that let you make progress?

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