CIP-???? | No Datum Is Unit

[zygomeb]

This CIP is a simple quality of life change. It defines a default interpretation of a utxo with no datum (defaulting to ()) for the purposes of scripts that were either erroneously created or make no use of datums.

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(draft proposal in branch)

[michaelpj]

This suggestion has been made a number of times before. I'm reluctant to adopt it for the reason listed here: #309 (comment)

[michaelpj]

This is not sufficiently specified. "unit datum" is not a thing. What value of type Data are you proposing?

[zygomeb]

It could be anything, really. I am personally split between List [] and I 0. In a future where we accept this proposal, which would you like this to be?

[michaelpj]

I disagree with using something like unit at all, see the linked comment. I would prefer something like Maybe X, but then again we have a representation problem.

[L-as]

I honestly don't see the point in this CIP. It's a very minor space optimisation that is arguably not clean.

[KtorZ]

This proposal falls under the Plutus' umbrella and seems to not be deemed as receivable. As discussed in today's editors meeting, we see two possible ways forward:

• Withdraw the proposal (i.e. close the PR)
• Mark the proposal as "Rejected", explain in the rationale why it is rejected (cf @michaelpj's comment) and merge it as such to keep a record of this decision.

[michaelpj]

Probably I should write a CPS about this where I lay out some of the questions that need to be answered by proposed solutions.

[zygomeb]

Probably I should write a CPS about this where I lay out some of the questions that need to be answered by proposed solutions.

That would be great -- I can close this PR or mark it as a rejected solution, although I would like to get some more insight as to why, @michaelpj, using a default value that could be supplied using a datum would be a bad design decision. (as in the linked PR)

Is there a case where this value being present, in a script-locking context, where it would otherwise be locked forever, be a bad thing?

[rphair]

@zygomeb since nothing has come of this since the Plutus team at the time deemed it "unreceivable" it's not likely that this could go anywhere today: therefore closing this as Abandoned - if a solution like you have outlined is still relevant after the Chang CIP-0069 update then please feel free to make your case & reopen this.