Bump @openzeppelin/contracts from 2.5.0 to 3.3.0

[dependabot-preview]

Bumps @openzeppelin/contracts from 2.5.0 to 3.3.0.

Release notes

Sourced from @openzeppelin/contracts's releases.

v3.2.1 for Solidity 0.7

This is a special release for Solidity 0.7 that gets rid of a warning in ERC777 using one of the new features of the language. (#2327)

Note: The variant for Solidity 0.7 can be installed using npm install @openzeppelin/contracts@solc-0.7.

v3.2.0

Welcome to a new release of OpenZeppelin Contracts! 👯

The big feature in this release is that we’ve migrated our proxy contracts from OpenZeppelin SDK into the Contracts project. We hope this will make more people aware of upgrades in Ethereum, and we also think the contracts will benefit greatly from the continued scrutiny by all of you in the community. This was also a migration of the proxies from Solidity 0.5 to 0.6, which we know some users have been waiting for.

For Solidity 0.7 users, a reminder that we have support for the newer compiler version published on npm under the tag solc-0.7, the latest release being 3.2.0-solc-0.7. We’re considering officially switching to 0.7 for the release after this one.

There is additionally a small breaking change in ERC20Snapshot that may affect some of its users. If you’re one of them please take a look at the changelog.

v3.1.0

This is the first release since v3.0, our last major release. It includes the long-awaited ERC1155 token and helpers for safe calls and downcasts, as well as a number of minor improvements.

To install this release, run:

npm install --save-dev @openzeppelin/contracts

ERC1155

This is a new token standard developed by the gaming industry, focusing on gas efficiency. It's key difference is that it is a multi-token contract: a single ERC1155 can be used to represent an arbitrary number of tokens, which is very useful in applications that require many tokens by removing the high gas costs associated with deploying them. Check out our new documentation page to learn more!.

More Replacements for call

The low-level call primitive can be hard to use correctly and is often considered unsafe. With the addition of sendValue in Contracts and try-catch in Solidity, there's only a few scenarios in which call is still needed, the most troublesome one being forwarding calls.

The new functionCall helpers can forward call data to a recipient contract while imitating Solidity's function call semantics, such as bubbling up revert reasons and rejecting calls to EOAs. We expect the addition of these functions to greatly reduce the need to rely on call.

Using SafeMath on Small Signed Integers

We've expanded the scope of the SafeCast library to also include signed integer downcasting, which allows for users that need small types (such as int8 or int32) to perform checked arithmetic on them by using SafeMath, and then downcast the result to the intended size.

OpenZeppelin Contracts 3.0.1

This is a small bugfix release, addressing an issue that allowed for some internal functions in ERC777 to be called with the zero address as one of their arguments.

This was reported in OpenZeppelin/openzeppelin-contracts#2208, fixed in OpenZeppelin/openzeppelin-contracts#2212 for the v2.5 branch, and ported to the v3.0 branch in OpenZeppelin/openzeppelin-contracts#2213.

OpenZeppelin Contracts 3.0

We're thrilled to finally announce the release of OpenZeppelin Contracts v3.0 ✨

Among other things, this release features the migration to Solidity v0.6, as well as a revamped access control system, streamlined token contracts, and new libraries for enumerable mappings.

To install this latest release, run:

Changelog

Sourced from @openzeppelin/contracts's changelog.

3.3.0 (2020-11-26)

• Now supports both Solidity 0.6 and 0.7. Compiling with solc 0.7 will result in warnings. Install the solc-0.7 tag to compile without warnings.
• Address: added functionStaticCall, similar to the existing functionCall. (#2333)
• TimelockController: added a contract to augment access control schemes with a delay. (#2354)
• EnumerableSet: added Bytes32Set, for sets of bytes32. (#2395)

3.2.0 (2020-09-10)

New features

• Proxies: added the proxy contracts from OpenZeppelin SDK. (#2335)

Proxy changes with respect to OpenZeppelin SDK

Aside from upgrading them from Solidity 0.5 to 0.6, we've changed a few minor things from the proxy contracts as they were found in OpenZeppelin SDK.

• UpgradeabilityProxy was renamed to UpgradeableProxy.
• AdminUpgradeabilityProxy was renamed to TransparentUpgradeableProxy.
• Proxy._willFallback was renamed to Proxy._beforeFallback.
• UpgradeabilityProxy._setImplementation and AdminUpgradeabilityProxy._setAdmin were made private.

Improvements

• Address.isContract: switched from extcodehash to extcodesize for less gas usage. (#2311)

Breaking changes

• ERC20Snapshot: switched to using _beforeTokenTransfer hook instead of overriding ERC20 operations. (#2312)

This small change in the way we implemented ERC20Snapshot may affect users who are combining this contract with other ERC20 flavors, since it no longer overrides _transfer, _mint, and _burn. This can result in having to remove Solidity override(...) specifiers in derived contracts for these functions, and to instead have to add it for _beforeTokenTransfer. See Using Hooks in the documentation.

3.1.0 (2020-06-23)

New features

• SafeCast: added functions to downcast signed integers (e.g. toInt32), improving usability of SignedSafeMath. (#2243)
• functionCall: new helpers that replicate Solidity's function call semantics, reducing the need to rely on call. (#2264)
• ERC1155: added support for a base implementation, non-standard extensions and a preset contract. (#2014, #2230)

Improvements

• ReentrancyGuard: reduced overhead of using the nonReentrant modifier. (#2171)
• AccessControl: added a RoleAdminChanged event to _setAdminRole. (#2214)
• Made all public functions in the token preset contracts virtual. (#2257)

Deprecations

• SafeERC20: deprecated safeApprove. (#2268)

3.0.2 (2020-06-08)

Improvements

• Added SPX license identifier to all contracts. (#2235)

Commits

• 6be5ffe 3.3.0
• ba843f0 Fix release script
• 4297be6 Use custom ids for timelock docs section titles
• d2003a6 Fix NatSpec comment syntax
• 1fccf6f 3.3.0-rc.2
• 7f8fc58 Remove Address.functionDelegateCall
• 1d1d2ba Add mention of TimelockController in intro to access docs
• 3881175 Fix TimelockController link in changelog
• f7bb84c Add changelog entry about support for both 0.6 and 0.7
• c67d81b 3.3.0-rc.1
• Additional commits viewable in compare view

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Superseded by #69.