ERC777
: fixed the_send
and_approve
internal functions not validating some of their arguments for non-zero addresses. (#2212)
SafeCast.toUintXX
: new library for integer downcasting, which allows for safe operation on smaller types (e.g.uint32
) when combined withSafeMath
. (#1926)ERC721Metadata
: addedbaseURI
, which can be used for dramatic gas savings when all token URIs share a prefix (e.g.http://api.myapp.com/tokens/<id>
). (#1970)EnumerableSet
: new library for storing enumerable sets of values. OnlyAddressSet
is supported in this release. (#2061)Create2
: simple library to make usage of theCREATE2
opcode easier. (#1744)
ERC777
:_burn
is now internal, providing more flexibility and making it easier to create tokens that deflate. (#1908)ReentrancyGuard
: greatly improved gas efficiency by using the net gas metering mechanism introduced in the Istanbul hardfork. (#1992, #1996)ERC777
: improve extensibility by making_send
and related functionsinternal
. (#2027)ERC721
: improved revert reason when transferring tokens to a non-recipient contract. (#2018)
ERC165Checker
now requires a minimum Solidity compiler version of 0.5.10. (#1829)
Address.toPayable
: added a helper to convert between address types without having to resort to low-level casting. (#1773)- Facilities to make metatransaction-enabled contracts through the Gas Station Network. (#1844)
Address.sendValue
: added a replacement to Solidity'stransfer
, removing the fixed gas stipend. (#1962)- Added replacement for functions that don't forward all gas (which have been deprecated): (#1976)
PullPayment.withdrawPaymentsWithGas(address payable payee)
Escrow.withdrawWithGas(address payable payee)
SafeMath
: added support for custom error messages tosub
,div
andmod
functions. (#1828)
Address.isContract
: switched fromextcodesize
toextcodehash
for less gas usage. (#1802)ERC20
andERC777
updated to throw custom errors on subtraction overflows. (#1828)
- Deprecated functions that don't forward all gas: (#1976)
PullPayment.withdrawPayments(address payable payee)
Escrow.withdraw(address payable payee)
Address
now requires a minimum Solidity compiler version of 0.5.5. (#1802)SignatureBouncer
has been removed from drafts, both to avoid confusions with the GSN andGSNRecipientSignature
(previously calledGSNBouncerSignature
) and because the API was not very clear. (#1879)
The final 2.4.0 release includes a refactor of the GSN contracts that will be a breaking change for 2.4.0-beta users.
- The default empty implementations of
_preRelayedCall
and_postRelayedCall
were removed and must now be explicitly implemented always in custom recipients. If your custom recipient didn't include an implementation, you can provide an empty one. GSNRecipient
,GSNBouncerBase
, andGSNContext
were all merged intoGSNRecipient
.GSNBouncerSignature
andGSNBouncerERC20Fee
were renamed toGSNRecipientSignature
andGSNRecipientERC20Fee
.- It is no longer necessary to inherit from
GSNRecipient
when usingGSNRecipientSignature
andGSNRecipientERC20Fee
.
For example, a contract using GSNBouncerSignature
would have to be changed in the following way.
-contract MyDapp is GSNRecipient, GSNBouncerSignature {
+contract MyDapp is GSNRecipientSignature {
Refer to the table below to adjust your inheritance list.
2.4.0-beta | 2.4.0 |
---|---|
GSNRecipient, GSNBouncerSignature |
GSNRecipientSignature |
GSNRecipient, GSNBouncerERC20Fee |
GSNRecipientERC20Fee |
GSNBouncerBase |
GSNRecipient |
ERC1820
: added support for interacting with the ERC1820 registry contract (IERC1820Registry
), as well as base contracts that can be registered as implementers there. (#1677)ERC777
: support for the ERC777 token, which has multiple improvements overERC20
(but is backwards compatible with it) such as built-in burning, a more straightforward permission system, and optional sender and receiver hooks on transfer (mandatory for contracts!). (#1684)- All contracts now have revert reason strings, which give insight into error conditions, and help debug failing transactions. (#1704)
- Reverted the Solidity version bump done in v2.2.0, setting the minimum compiler version to v0.5.0, to prevent unexpected build breakage. Users are encouraged however to stay on top of new compiler releases, which usually include bugfixes. (#1729)
PostDeliveryCrowdsale
: some validations where skipped when paired with other crowdsale flavors, such asAllowanceCrowdsale
, orMintableCrowdsale
andERC20Capped
, which could cause buyers to not be able to claim their purchased tokens. (#1721)ERC20._transfer
: thefrom
argument was allowed to be the zero address, so it was possible to internally trigger a transfer of 0 tokens from the zero address. This address is not a valid destinatary of transfers, nor can it give or receive allowance, so this behavior was inconsistent. It now reverts. (#1752)
ERC20Snapshot
: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time. (#1617)SafeERC20
:ERC20
contracts with no return value (i.e. that revert on failure) are now supported. (#1655)ERC20
: added internal_approve(address owner, address spender, uint256 value)
, allowing derived contracts to set the allowance of arbitrary accounts. (#1609)ERC20Metadata
: added internal_setTokenURI(string memory tokenURI)
. (#1618)TimedCrowdsale
: added internal_extendTime(uint256 newClosingTime)
as well asTimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime)
event allowing to extend the crowdsale, as long as it hasn't already closed.
- Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives. (#1606)
ECDSA
:recover
no longer accepts malleable signatures (those using upper-range values fors
, or 0/1 forv
). (#1622)ERC721
's transfers are now more gas efficient due to removal of unnecessarySafeMath
calls. (#1610)- Fixed variable shadowing issues. (#1606)
- (minor)
SafeERC20
:safeApprove
wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. (#1647)
TokenMetadata
has been renamed toERC20Metadata
. (#1618)- The library
Counter
has been renamed toCounters
and its API has been improved. See an example inERC721
, lines 17 and 204. (#1610)
- Backported
SafeERC20.safeApprove
bugfix. (#1647)
- Removed most of the test suite from the npm package, except
PublicRole.behavior.js
, which may be useful to users testing their ownRoles
.
- Version bump to avoid conflict in the npm registry.
- Now targeting the 0.5.x line of Solidity compilers. For 0.4.24 support, use version 2.0 of OpenZeppelin.
WhitelistCrowdsale
: a crowdsale where only whitelisted accounts (WhitelistedRole
) can purchase tokens. Adding or removing accounts from the whitelist is done by whitelist admins (WhitelistAdminRole
). Similar to the pre-2.0WhitelistedCrowdsale
. (#1525, #1589)RefundablePostDeliveryCrowdsale
: replacement forRefundableCrowdsale
(deprecated, see below) where tokens are only granted once the crowdsale ends (if it meets its goal). (#1543)PausableCrowdsale
: allows for pausers (PauserRole
) to pause token purchases. Other crowdsale operations (e.g. withdrawals and refunds, if applicable) are not affected. (#832)ERC20
:transferFrom
and_burnFrom
now emitApproval
events, to represent the token's state comprehensively through events. (#1524)ERC721
: added_burn(uint256 tokenId)
, replacing the similar deprecated function (see below). (#1550)ERC721
: added_tokensOfOwner(address owner)
, allowing to internally retrieve the array of an account's owned tokens. (#1522)- Crowdsales: all constructors are now
public
, meaning it is not necessary to extend these contracts in order to deploy them. The exception isFinalizableCrowdsale
, since it is meaningless unless extended. (#1564) SignedSafeMath
: added overflow-safe operations for signed integers (int256
). (#1559, #1588)
- The compiler version required by
Array
was behind the rest of the libray so it was updated tov0.4.24
. (#1553) - Now conforming to a 4-space indentation code style. (1508)
ERC20
: more gas efficient due to removed redundantrequire
s. (#1409)ERC721
: fixed a bug that prevented internal data structures from being properly cleaned, missing potential gas refunds. (#1539 and #1549)ERC721
: general gas savings ontransferFrom
,_mint
and_burn
, due to redudantrequire
s andSSTORE
s. (#1549)