Release v0.42.0

[xgreenx]

Version v0.42.0

Changed

Breaking

• #629: Charge the user for VM initialization.

• #628: Renamed transaction::CheckError to transaction::ValidityError.
  Created a new checked_transaction::CheckError that combines ValidityError
  and PredicateVerificationFailed errors into one. It allows the return of the
  PredicateVerificationFailed to the end user instead of losing the reason why predicate verification failed.

• #625: Use ArithmeticError only for arithmetic operations, and introduce new errors like BalanceOverflow for others. Whenever an error is internally caused by a type conversion to usize, so that an overflowing value wouldn't map to a valid index anyway, return the missing item error instead.

• #623:
  Added support for transaction policies. The Script and Create
  transactions received a new field, policies. Policies allow the addition
  of some limits to the transaction to protect the user or specify some details regarding execution.
  This change makes the GasPrice and Maturity fields optional, allowing to save space in the future.
  Also, this will enable us to support multidimensional prices later.
  GasLimit was renamed to ScriptGasLimit.

  Along with this change, we introduced two new policies:

  • WitnessLimit - allows the limitation of the maximum size of witnesses in bytes for the contract. Because of the changes in the gas calculation model(the blockchain also charges the user for the witness data), the user should protect himself from the block producer or third parties blowing up witness data and draining the user's funds.
  • MaxFee - allows the upper bound for the maximum fee that users agree to pay for the transaction.

  This change brings the following modification to the gas model:

  • The ScriptGasLimit only limits script execution. Previously, the ScriptGasLimit also limited the predicate execution time, instead predicate gas is now directly included into min_fee. So, it is not possible to use the ScriptGasLimit for transaction cost limitations. A new MaxFee policy is a way to do that. The GasLimit field was removed from the Create transaction because it only relates to the script execution (which the Create transaction doesn't have).
  • The blockchain charges the user for the size of witness data (before it was free). There is no separate price for the storage, so it uses gas to charge the user. This change affects min_gas and min_fee calculation.
  • A new policy called WitnessLimit also impacts the max_gas and max_fee calculation in addition to ScriptGasLimit(in the case of Create transaction only WitnessLimit affects the max_gas and max_fee).
  • The minimal gas also charges the user for transaction ID calculation.

  The change has the following modification to the transaction layout:

  • The Create transaction doesn't have the ScriptGasLimit field anymore. Because the Create transaction doesn't have any script to execute
  • The Create and Script transactions don't have explicit maturity and gas_price fields. Instead, these fields can be set via a new policies field.
  • The Create and Script transactions have a new policies field with a unique canonical serialization and deserialization for optimal space consumption.

  Other breaking changes caused by the change:

  • Each transaction requires setting the GasPrice policy.
  • Previously, ScriptGasLimit should be less than the MAX_GAS_PER_TX constant. After removing this field from the Create transaction, it is impossible to require it. Instead, it requires that max_gas <= MAX_GAS_PER_TX for any transaction. Consequently, any Script transaction that uses MAX_GAS_PER_TX as a ScriptGasLimit will always fail because of a new rule. Setting the estimated gas usage instead solves the problem.
  • If the max_fee > policies.max_fee, then transaction will be rejected.
  • If the witnessses_size > policies.witness_limit, then transaction will be rejected.
  • GTF opcode changed its hardcoded constants for fields. It should be updated according to the values from the specification on the Sway side.

• #633: Limit receipt count to u16::MAX.

• #634: Charge for storage per new byte written. Write opcodes now return the number of new storage slots created, instead of just a boolean on whether the value existed before.

Fixed

• #627: Added removal of obsolete SMT nodes along the path during update and delete operations.

What's Changed

• Support transaction policies by @xgreenx in Support transaction policies #623
• Remove SMT nodes along the path during update by @xgreenx in Remove SMT nodes along the path during update #627
• Limit ReceiptsCtx to u16::MAX receipts by @Dentosal in Limit ReceiptsCtx to u16::MAX receipts #633
• Charge the user for VM initialization by @xgreenx in Charge the user for VM initialization #629
• Return PredicateVerificationFailed error to the user by @xgreenx in Return PredicateVerificationFailed error to the user #628
• Split ArithmeticError into more granular errors by @Dentosal in Split ArithmeticError into more granular errors #625
• Charge for new storage bytes by @Dentosal in Charge for new storage bytes #634

Full Changelog: v0.41.0...v0.42.0