English Auction

⚠️ Experimental — generated with no human supervision by the daily MCP pipeline (Solidity→Gno port). Not audited. See r/moul/x/daily.

An idiomatic gno.land port of the classic Solidity English (ascending-bid) auction. It ports the core mechanics — a seller opens an auction, bidders submit strictly increasing bids, the displaced top bid becomes refundable, and after a block deadline anyone can settle it — into a single realm that hosts many concurrent auctions.

Solidity's msg.sender maps to unsafe.PreviousRealm().Address(), block.number to runtime.ChainHeight(), require to panic, and events to chain.Emit. There is no real coin transfer: bid amounts and refunds are tracked as plain uint64 accounting in ordered avl.Trees (mirroring Solidity's pendingReturns withdraw pattern). Auctions and pending refunds are keyed so Render can iterate deterministically.

Transactions

• Start(cur, item string, durationBlocks int64) int64 — open an auction (caller becomes the seller); ends at ChainHeight() + durationBlocks. Returns the id.
• Bid(cur, id int64, amount uint64) — bid; must strictly exceed the current highest. The prior top bid becomes refundable.
• Withdraw(cur, id int64) uint64 — reclaim your displaced bids for an auction.
• End(cur, id int64) — after the deadline, award the item to the top bidder.

Example calls

# open a 100-block auction for a painting -> returns id 1
Start("Vintage painting", 100)

# two bidders compete (amounts are accounting units, not real coins)
Bid(1, 500)     # alice
Bid(1, 750)     # bob outbids -> alice's 500 is now refundable
Withdraw(1)     # alice reclaims 500

# once ChainHeight() >= endHeight, anyone settles it
End(1)          # item awarded to bob at 750

Visit the realm to see the live table of auctions: item, highest bid + bidder, blocks remaining or ended, and the winner.

What changed in v1

State moved from a hand-rolled avl.Tree + nextID + zero-padding helper to p/moul/kit/store, which keys entries by seqid instead of a fixed-width decimal string.

v0 padded ids to width 12. Past that width the padding stops and the tree orders "1000000000000" before "999999999999", so every list this realm renders would be wrong from that entry on. store keys are 8 big-endian bytes whose order is numeric for every uint64, so there is no width left to outgrow.

Auction loses its ID field, which the store now owns, and the local mustGet becomes one line: the store's labelled MustGet panics englishauction: auction #7 not found where v0 said only englishauction: no such auction.

pending, the refund ledger, keeps its own tree and its composite "<id>:<addr>" key, now built from the plain decimal id instead of the padded one. It is only ever point-read, never iterated, so it needs a readable key and not an ordered one. Auction ids already started at 1, so nothing shifts.

This is a storage change, which under this repo's versioning rule is a compatibility change, hence a new version rather than an edit in place. v0 stays live and untouched.

Part of moul/gno-contracts — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

Dependency graph:

🧪 Highly experimental — potentially vibe-coded. Not audited; may break, change, or be removed at any time. Do not use with anything of value. Full disclaimer: DISCLAIMER.