Add Auction Pallet

[indirection42]

Description

This PR is part of #9765. This PR introduces pallet-auction, a new FRAME pallet that provides a generic framework for on-chain auctions. The pallet allows for the creation and management of auctions for any type of asset, with customizable logic through the AuctionHandler trait.

The auction pallet implements a flexible auction mechanism that can be used to implement various auction types, such as English auctions, Dutch auctions, or other custom formats. It provides a standard interface through the Auction trait so other pallets can query and update auctions via a shared API.

Integration

This PR introduces a new pallet (pallet-auction) that downstream projects can integrate into their runtime. The integration requires:

1. Runtime Configuration: Add the auction pallet to your runtime's construct_runtime! macro
2. Handler Implementation: Implement the AuctionHandler trait to define custom auction logic
3. Type Configuration: Configure the required types (Balance, AuctionId) in your runtime's config

Example integration:

impl pallet_auction::Config for Runtime {
    type Balance = Balance;
    type AuctionId = u32;
    type Handler = YourAuctionHandler;
    type WeightInfo = pallet_auction::weights::SubstrateWeight<Runtime>;
}

The pallet is designed to be generic and can work with any asset type through the handler implementation.

Review Notes

Implementation Details

The auction pallet uses a simple but effective storage design:

• Auctions<T>: Maps auction IDs to auction information including current bid and timing
• AuctionEndTime<T>: Double map from end block to auction ID for efficient batch processing of ending auctions
• AuctionsIndex<T>: Tracks the next available auction ID for new auction creation

Key Features

• Generic Auction Mechanism: Can be used for auctioning any asset
• Customizable Logic: The AuctionHandler trait allows for custom implementation of auction logic
• Scheduled Auctions: Auctions can be scheduled to start at a future block number
• Automatic Auction Closing: Auctions are automatically closed at their end block number in the on_finalize hook
• Standard Interface: Implements the Auction trait for interoperability

Auction Lifecycle

1. Creation: Auctions are created with a start block and optional end block via new_auction()
2. Active Phase: Bids can be placed during the active period via bid()
3. Bid Processing: Each bid is validated by the handler and may extend the auction
4. Conclusion: Auctions are automatically concluded at their end block

Storage Efficiency

The pallet uses efficient storage patterns:

• Double map for AuctionEndTime allows batch processing of ending auctions
• Automatic cleanup of ended auctions prevents storage bloat
• Incremental auction ID generation prevents ID conflicts

Error Handling

The pallet includes comprehensive error handling:

• AuctionNotExist: For invalid auction IDs
• AuctionNotStarted: For bids placed before auction start
• BidNotAccepted: For bids rejected by the handler
• InvalidBidPrice: For invalid bid amounts
• NoAvailableAuctionId: For auction ID overflow

Security Considerations

• All bid operations require signed origins
• Bid validation is enforced both at the pallet level and through the handler
• Auction timing is enforced through block number checks
• Storage operations are atomic to prevent inconsistent states

Checklist

• My PR includes a detailed description as outlined in the "Description" and its two subsections above.
• My PR follows the labeling requirements of this project (at minimum one label for T required)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[indirection42]

/cmd fmt

[indirection42]

/cmd --help

[indirection42]

/cmd label T1-FRAME