Function: reduce(byte[32] asset, address account, CLOBReduceArgs args)

This function reduces the amount of an existing open limit order (or fully cancels it). This function allows the user to lower the unfilled portion of an order without changing its price, side, or leverage.

When the order is reduced, the protocol updates the order’s amount, refunds the collateral associated with the removed amount, and keeps the order live in the order book (or cancels it if the amount becomes zero).

Branches and code coverage

Intended branches

• Updates orderAmount by correct delta.

  Test coverage

• Refunds the correct collateral amount (quoteAmount * price / leverage).

  Test coverage

• orderbookCollateral in the GTL contract is updated correctly.

  Test coverage

• Order is fully canceled when block.timestamp > cancelTimestamp even if amountInBase < orderAmount.

  Test coverage

• Order is fully canceled when args.amountInBase >= orderAmount.

  Test coverage

• Order is fully canceled when orderAmount - args.amountInBase < ds.settings.minLimitOrderAmountInBase.

  Test coverage

• quoteTokenOpenInterest is updated properly when side == Side.BUY.

  Test coverage

• baseTokenOpenInterest is updated properly when side == Side.SELL.

  Test coverage

Negative behavior

• Order does not exist.

  Negative test

• Tries to cancel again.

  Negative test

• Account is not an order owner.

  Negative test

• Reverts if provided amountInBase is greater than orderAmount.

  Negative test

• Reverts if provided amountInBase is zero.

  Negative test