Fanout and Decommit transactions don't include datum hash in outputs

[Micrograx]

Context & versions

cardano-node: 9.1
hdyra-node: 0.18.1
cardano-cli: 9.2.1

Steps to reproduce

1. Open a hydra head
2. Create a script UTxO with a datum hash inside the head (Or commit one from the start)
3. Close the head (Or create a decommit transaction with a script UTxO in the output)

Actual behavior

The submission of the transaction to the L1 will fail because the datum hash will not be included in the script UTxO

Expected behavior

Transaction should be submitted without issues

Workaround

Use inline datums or modify the transaction cbor to include the datum hash in the output. For the latter, you can get the transaction cbor from the hydra-node logs.

[v0d1ch]

Hey @Micrograx thanks for reporting this!

I've tried to put together some end-to-end tests on hydra to assert this behavior but could not reproduce the issue using all three ways (committing a script to a Head, decommiting a script UTxO and L2 transaction with datum hash in the output).

Could you perhaps provide more info on your workflow, how are you constructing the transactions, which library and versions? Anything that could help us pinpoint where the issue might be?

[Micrograx]

Hi @v0d1ch, thanks for your patience.

We've continued our testing using inline datums as described in the workaround section. I'll try to reproduce the issue in the 0.19.0 version of the hydra node and share more details next week. In short we've been doing all transaction building with the cardano-cli, and we were using the --tx-out-datum-hash-value argument to add the datum to the script outputs we want to fanout and decommit.

[v0d1ch]

No worries, thanks for the info 🙏
I will also use cardano-cli on my end to try and reproduce the bug.
What version of cardano-cli are you using? Just so we don't misalign on all important aspects to get to the same result.

[Micrograx]

I was using version 9.2.1 and the cardano-cli babbage transaction build set of commands, given that the 0.18 version of the hydra node didn't support conway transactions fully.