openzeppelin-contracts/CHANGELOG.md

Changelog

2.2.0 (unreleased)

New features:

• ERC20: added internal _approve(address owner, address spender, uint256 value), allowing derived contracts to set the allowance of arbitrary accounts.
• ERC20Metadata: added internal _setTokenURI(string memory tokenURI).
• ERC20Snapshot: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time.

Improvements:

• Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives.
• Counter's API has been improved, and is now used by ERC721 (though it is still in drafts).
• ERC721's transfers are now more gas efficient due to removal of unnecessary SafeMath calls.
• Fixed variable shadowing issues.

Bugfixes:

Breaking changes:

• TokenMetadata (in drafts) has been renamed to ERC20Metadata.

2.1.2 (2019-17-01)

• 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 (2019-04-01)

• Version bump to avoid conflict in the npm registry.

2.1.0 (2019-04-01)

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)