This is the first ink! release outside of Parity. ink! was started at Parity and during this year became a community project maintained by the ink! Alliance, a loose group of former Parity employees and teams who want ink! to ensure a bright future for ink!.

You can find more details about the community handover in this X post. Generally, the only thing changing on the user-facing side is that the repositories have been moved from paritytech to the new GitHub organization use-ink.

❣ We want to say a big thank you to our Polkadot community, which recently decided on funding the continued maintenance and development of ink! with a Polkadot Treasury grant.

Highlights

This version of ink! comes with three highlights plus some minor fixes.

(1) XCM Support

ink! 5.1 supports the usage of XCM in contracts, developers are no longer limited to cross-contract calls, but can now execute cross-parachain calls.

We added a contract example that demonstrates the usage: contract-xcm

We also added a new page on our documentation website: https://use.ink/basics/xcm.

You can view the Rust docs of the two functions here:

• xcm_send
• xcm_execute

(2) Call an ink! contract from a polkadot-sdk runtime

ink! 5.1 comes with basic support for calling contracts from a Polkadot runtime. We've added this example that demonstrates how to call flipper from a polkadot-sdk runtime pallet.

Calling a contract from the runtime is an interesting application for parachains, as they can put logic into a contract instead of their runtime. Contracts have a number of advantages, as they are easier to upgrade and allow for faster development iteration cycles.

The limitations currently are:

• Contract calls can only be made to trait messages. This makes sense in the pallet-contracts context, as it is better to depend on a trait rather than a contract impl, since you are working against an interface.
• Only contract messages can be called currently, no constructors.
• The API could be nicer.

(3) E2E Testing

We replaced our drink sandbox dependency with an internal ink! crate. In case you use DRink!:

First, you should upgrade your drink dependency to version = "0.18.0". Second, these are the two changes you have to make:

- #[ink_e2e::test(backend(runtime_only(sandbox = ink_e2e::MinimalSandbox)))]
+ #[ink_e2e::test(backend(runtime_only(sandbox = ink_e2e::DefaultSandbox)))]

- ink_e2e = { version = "5", features = ["drink"] }
+ ink_e2e = { version = "5", features = ["sandbox"] }

Compatibility

The compatibility changes a bit to ink! 5.0:

• Rust: >= 1.81
• cargo-contract: >= 5.0.0
• polkadot-sdk: >= v1.12.0
  (this release stabilized the pallet-contracts XCM functions that ink! uses)
• substrate-contracts-node: >= 0.42.0
• DRink!: >= 0.18.0

Added

• [Runtime-to-Contract Calls] Environment agnostic contract invocation API, for calling contracts from runtime ‒ #2219
• [Runtime-to-Contract Calls] Add no-panic-handler feature ‒ #2164
• [Runtime-to-Contract Calls] Add example for calling a contract from a runtime pallet ‒ #2189
• [XCM] Add xcm_execute and xcm_send support ‒ #1912
• [Linter] Add links to detailed lint description ‒ #2170
• [E2E] Adds a message to SandboxErr to add context for easier debugging ‒ #2218
• [E2E] Add ability to take and restore snapshots ‒ #2261 (thanks @0xLucca!)
• [E2E] Demonstrate usage of seeds for secret URIs in E2E test for chain snapshots ‒ #2163

Changed

• Update repository URLs & references from paritytech GitHub organization to new use-ink one ‒ #2220 and #2248
• [E2E] Update subxt and polkadot-sdk dependencies ‒ #2174
• [Drink backend] Replace drink sandbox with internal ink_sandbox ‒ #2158

Fixed

• [XCM] Fix XCM-support to single encode the XCM message ‒ #2278
• [Examples] ERC-721: burn() clears token approval ‒ #2099
• [E2E] Fix outdated docs for [ink_e2e::test] ‒ #2162
• [E2E] Build contracts before initializing node rpc ‒ #2168
• [E2E] set_account_balance now can't set balance below existential deposit ‒ #1983 (thanks @0xLucca!)
• [E2E] Fix outdated docs for [ink_e2e::test] ‒ #2162