ink! 3.0.0 RC 4

Version 3.0-rc4 (2021-07-19)

This is the 4th release candidate for ink! 3.0.

The list below shows the additions, changes and fixes that are visible to users of ink!.

Compatibility

ink! 3.0-rc4 is compatible with

• The "ink! CLI" cargo-contract
  version 0.13.0 or newer.
  • Install the newest version using cargo install --force cargo-contract.
• Substrate version 4.0.0-dev including the contracts-pallet version 4.0.0-dev.
• canvas-node version 0.19.0 or newer.
  • Install the newest version using cargo install canvas-node --git https://github.com/paritytech/canvas-node.git --force.

The documentation on our Documentation Portal
is up to date with this release candidate. Since the last release candidate we notabley
added a number of Frequently Asked Questions
there.

Quality Assurance

In order to ensure a continuously high quality of our codebase we implemented a number
of key improvements to our testing setup:

• We've put an emphasis on automated testing of the usage examples in our crate documentation.
  Those are now tested in the context of a complete ink! contract. In the past this was not
  always the case, sometimes usage examples were just isolated code snippets.
• We started our ink-waterfall project,
  which runs End-to-End tests through our entire stack.
  All our examples are continuously built using the latest cargo-contract. They are
  subsequently deployed on the latest canvas-node by emulating browser interactions with
  both the canvas-ui and the
  polkadot-js UI.
  This testing setup enables us to detect bugs which only appear in the context of using
  multiple components together early on.
• To improve the readability of our documentation we introduced automated grammar and spell
  checking into our Continuous Integration environment.

Added

• Added support for the new seal_random API ‒ #734.
• Added missing documentation for the ink_storage_derive procedural macros ‒ #711.
• Implemented the (unstable) seal_rent_params API ‒ #755.
• Implemented the (unstable) seal_rent_status API ‒ #798.
• Implemented the (unstable) seal_debug_message API ‒ #792.
  • Printing debug messages can now be achieved via ink_env::debug_println!(…).
  • See our documentation
    for more information.
  • The examples have been updated to reflect this new way of printing debug messages.
• Added usage comments with code examples to the ink_env API ‒ #797.
  • The published crate documentation now contains
    much more code examples for the methods behind self.env() and Self::env().
• Added an example implementation for ERC-1155, a multi-token standard ‒ #800.
• Implemented binary search for collections::Vec ‒ #836.
• Added the ability of submitting payable transactions to the multisig example ‒ #820.
• Implemented Decode for Error types in the examples, enabling building them as dependencies ‒ #761.
• We started working on a new off-chain environment testing engine ‒ #712.
  • The old testing environment has a number of limitations, which we are well aware of.
    We're confident that with the new testing engine we will be able to conduct much more
    elaborate testing in an emulated chain environment.
  • For the moment, the new engine is unstable and only available behind a feature flag.
    A number of examples have already been converted to support the new testing engine.

Changed

• To reduce a contract's space footprint we switched the default allocator to a bump allocator implementation ‒ #831.
• A couple of readme's have been reworked:
  • Our main ink! readme ‒ #774.
  • The rand-extension example readme ‒ #793.
  • The delegator example readme ‒ #766.
• With the stabilization of Rust 1.51 we ware able to remove the ink-unstable feature, making
  collections::SmallVec and lazy::LazyArray available by default ‒ #746.
• To resolve confusion, we migrated all usages of #[test] in our examples to #[ink::test] ‒ #746.
  • The difference is that #[ink::test] spawns an emulated chain environment (an "off-chain" environment)
    and hence comes with a bit of overhead. It was not always clear to users when they require
    an off-chain environment, we decided to mitigate this confusion by using an emulated chain
    environment for all our example tests.
• With the stabilization of Rust's min_const_generics we were able to replace the fixed
  size implementations of SpreadLayout and PackedLayout for Arrays. These traits are
  now implemented for all Arrays of size usize ‒ #754.
• We were able to remove the pinned funty dependency ‒ #711.
• The contract-transfer example has been improved for better UI support ‒ #789.
• The contract-transfer example has been improved for better error handling ‒ #790.

Fixed

• Catch illegal struct destructuring pattern in ink! message arguments ‒ #846.
• Removed an erroneous Salt type in code generation for cross-contract calls ‒ #842.
• Do not generate metadata if compiled as dependency ‒ #811.
• Fix execution context parameters in DNS example tests ‒ #723.
• Fixed the Greeter contract example from our doc comments ‒ #773.