Function: modifyRailPayment(uint256 railId, uint256 newRate, uint256 oneTimePayment)

Modifies the payment rate and optionally makes a one-time payment.

Inputs

• railId

  • Control: Fully controlled by the caller.

  • Constraints: Must be a valid, active rail that the caller is an operator of.

  • Impact: The ID of the rail to modify.

• newRate

  • Control: Fully controlled by the caller.

  • Constraints: For terminated rails, it cannot exceed the existing rate. Otherwise, the rail must be settled in order to modify it.

  • Impact: The new payment rate (per epoch). This new rate applies starting the next epoch after the current one.

• oneTimePayment

  • Control: Fully controlled by the caller.

  • Constraints: Cannot exceed the rail's current lockupFixed.

  • Impact: Optional one-time payment amount to transfer immediately, taken out of the rail's fixed lockup.

Branches and code coverage

Intended branches

• Caller is a valid operator, new rate is equal to old rate, no one time payment.

  Test coverage

• Caller is a valid operator, new rate is equal to old rate, has one time payment.

  Test coverage

• Caller is a valid operator, new rate is lower than the old rate, no one time payment.

  Test coverage

• Caller is a valid operator, new rate is lower than the old rate, has one time payment.

  Test coverage

• Caller is a valid operator, new rate is higher than the old rate, no one time payment.

  Test coverage

• Caller is a valid operator, new rate is higher than the old rate, has one time payment.

  Test coverage

• Caller is a valid operator, the rail is terminated and the rate is equal to the old rate.

  Test coverage

Negative behavior

• Caller is a valid operator and tries to do a one time payment with insufficient funds.

  Negative test

• Caller is not a valid operator.

  Negative test

• Caller is a valid operator and tries to call the function on a terminated rail after the end epoch.

  Negative test

• Caller is a valid operator and tries to increase the rate of a terminated rail.

  Negative test

• Rail is not terminated, but lockup rate is less than the old rate.

  Negative test

Function call analysis

None of the functions do external calls, just internal book keeping.

• Payments.modifyRailPayment->enqueueRateChange(rail, oldRate, newRate)

  • Inserts the rate change into the rail's rail.rateChangeQueue.

• Payments.modifyRailPayment->updateOperatorRateUsage

  • If rail rate is modified, this internally updates approval.rateUsage to account for the increased or decreased rate.

• Payments.modifyRailPayment->updateOperatorLockupUsage

  • If rail rate is modified, this internally updates approval.lockupUsage to account for the increased or decreased rate.

• Payments.modifyRailPayment->updateOperatorAllowanceForOneTimePayment

  • If a one time payment is included, this subtracts the payment from approval.lockupUsage and approval.lockupAllowance.

• Payments.modifyRailPayment->processOneTimePayment

  • If there is an optional one time payment, this is subtracted from the payer's funds, crediting it with any fees paid while doing so.