Rough thoughts on OP_EXPIRE:
1. Optimizes the unhappy path for contract timeout (you don't need another TX to timeout). Though timeout is usually unlikely, there are cases like atomic swaps where you have to charge for it to avoid griefers.
2. You want both relative and absolute.
3. Adds another reason to do mempool eviction, not just double spends, fee increases and timeouts. May be interesting to implement.
4. You want this in an address format too, in consensus, so you can create expiring addresses. Relative doesn't seem to make sense here.
The last is a different use case, but currently expiry is implied and not enforceable, yet watching an address forever is not realistic. 10 years max, for a donation sp address, I would think.
I'm broadly supportive, as an incremental improvement.
Rusty Russell
npub179…elz4s
2025-11-25 23:15:10 UTC
Author Public Key
npub179e9tp4yqtqx4myp35283fz64gxuzmr6n3yxnktux5pnd5t03eps0elz4sPublished at
2025-11-25 23:15:10 UTCEvent JSON
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"content": "Rough thoughts on OP_EXPIRE:\n1. Optimizes the unhappy path for contract timeout (you don't need another TX to timeout). Though timeout is usually unlikely, there are cases like atomic swaps where you have to charge for it to avoid griefers.\n2. You want both relative and absolute.\n3. Adds another reason to do mempool eviction, not just double spends, fee increases and timeouts. May be interesting to implement. \n4. You want this in an address format too, in consensus, so you can create expiring addresses. Relative doesn't seem to make sense here.\n\nThe last is a different use case, but currently expiry is implied and not enforceable, yet watching an address forever is not realistic. 10 years max, for a donation sp address, I would think.\n\nI'm broadly supportive, as an incremental improvement. ",
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