openzeppelin-contracts/CHANGELOG.md

Changelog

2.3.0 (unreleased)

New features:

• 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: initial support for the ERC777 token, which has multiple improvements over ERC20 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)

Improvements:

• Upgraded the minimum compiler version to v0.5.7: this prevents users from encountering compiler bugs that were fixed in this version. (#1724)

Bugfixes:

• PostDeliveryCrowdsale: some validations where skipped when paired with other crowdsale flavors, such as AllowanceCrowdsale, or MintableCrowdsale and ERC20Capped, which could cause buyers to not be able to claim their purchased tokens. (#1721)

2.2.0 (2019-03-14)

New features:

• 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 as TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime) event allowing to extend the crowdsale, as long as it hasn't already closed.

Improvements:

• 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 for s, or 0/1 for v). (#1622)
• ERC721's transfers are now more gas efficient due to removal of unnecessary SafeMath calls. (#1610)
• Fixed variable shadowing issues. (#1606)

Bugfixes:

• (minor) SafeERC20: safeApprove wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. (#1647)

Breaking changes in drafts:

• TokenMetadata has been renamed to ERC20Metadata. (#1618)
• The library Counter has been renamed to Counters and its API has been improved. See an example in ERC721, lines 17 and 204. (#1610)

2.1.3 (2019-02-26)

• Backported SafeERC20.safeApprove bugfix. (#1647)

2.1.2 (2019-01-17)

• Removed most of the test suite from the npm package, except PublicRole.behavior.js, which may be useful to users testing their own Roles.

2.1.1 (2019-01-04)

• Version bump to avoid conflict in the npm registry.

2.1.0 (2019-01-04)

New features:

• 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-2.0 WhitelistedCrowdsale. (#1525, #1589)
• RefundablePostDeliveryCrowdsale: replacement for RefundableCrowdsale (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 emit Approval 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 is FinalizableCrowdsale, since it is meaningless unless extended. (#1564)
• SignedSafeMath: added overflow-safe operations for signed integers (int256). (#1559, #1588)

Improvements:

• The compiler version required by Array was behind the rest of the libray so it was updated to v0.4.24. (#1553)
• Now conforming to a 4-space indentation code style. (1508)
• ERC20: more gas efficient due to removed redundant requires. (#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 on transferFrom, _mint and _burn, due to redudant requires and SSTOREs. (#1549)

Bugfixes:

Breaking changes:

Deprecations:

• ERC721._burn(address owner, uint256 tokenId): due to the owner parameter being unnecessary. (#1550)
• RefundableCrowdsale: due to trading abuse potential on crowdsales that miss their goal. (#1543)