What is new way to implement custom data structs (in ink! 4)?

Question

I am trying to upgrade then compile a token contract (employing openbrush) from ink!3 to ink!4.

My understanding is that SpreadAllocate, StorageLayout, etc. have been removed from the ink!4 release.

The problem is that I have custom data structures that cargo still expects the StorageLayout trait to be implemented for.

How do I work around this?

Context:

• this is built using cargo-contract version 2.0.0-beta
• this project uses Openbrush 3 (Cargo.toml included below)

Here are the structs in question:

    #[derive(scale::Encode, scale::Decode, Clone)]
    #[cfg_attr(
    feature = "std",
    derive(scale_info::TypeInfo)
    )]
    #[derive(Debug)]
    pub struct StakeholderData {
        paid: Balance,
        share: Balance,
        pool: u8,
    }

    #[derive(scale::Encode, scale::Decode, Clone, Default)]
    #[cfg_attr(
    feature = "std",
    derive(scale_info::TypeInfo)
    )]
    pub struct Port {
        hash: Hash,
        tax: Balance,
        cap: Balance,
        locked: bool,
        paid: Balance,
        collected: Balance,
    }

    #[derive(scale::Encode, scale::Decode, Clone, Default)]
    #[cfg_attr(
    feature = "std",
    derive(scale_info::TypeInfo)
    )]
    pub struct Socket {
        address: AccountId,
        port: u16,
    }

Cargo.toml below:

[package]
name = "ilocktoken"
version = "0.1.0"
authors = ["Blair Munro <[email protected]>"]
edition = "2021"

# This is to enable unsigned integer division (floor division)
# ...safe-math functions are used for lib.rs arithmetic where overflow checks would otherwise be
#    (that is, in all cases except the few floor division operations)
[profile.release]
overflow-checks = false

[dependencies]
ink = { git = "https://github.com/paritytech/ink", commit = "4655a8b4413cb50cbc38d1b7c173ad426ab06cde", default-features = false }

scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["derive"] }
scale-info = { version = "2.3", default-features = false, features = ["derive"], optional = true }

openbrush = { tag = "3.0.0-beta", git = "https://github.com/727-Ventures/openbrush-contracts", default-features = false, features = ["psp22", "ownable"] }
[lib]
name = "ilocktoken"
path = "lib.rs"
crate-type = [
    # Used for normal contract Wasm blobs.
    "cdylib",
]

[features]
default = ["std"]
std = [
    "ink/std",
    "scale/std",
    "scale-info/std",

    "openbrush/std",
]

ink-as-dependency = []

And here is a screenshot of the cargo build log:

Thank you for the insight and understanding.

Answer 1

Easy fix. I was mistaken to assert that ink!4 does not have the StorageLayout trait.

Per ink multisig reference implementation, StorageLayout must be be derived as so:

    #[derive(scale::Encode, scale::Decode, Clone, Default)]
    #[cfg_attr(
    feature = "std",
    derive(
        Debug,
        PartialEq,
        Eq,
        scale_info::TypeInfo,
        ink::storage::traits::StorageLayout    // <----- ! derive as so
        )
    )]
    pub struct StakeholderData {
        paid: Balance,
        share: Balance,
        pool: u8,
    }