error[E0277]: the trait bound `Project: Serialize` is not satisfied, note: required by a bound in `near_sdk::serde_json::to_vec`

Question

#[derive(BorshDeserialize, BorshSerialize, Debug)]
pub struct Project {
    pub name: String,
    pub description: String,
    pub image: String,
    pub owner: AccountId,
    pub supporters: UnorderedMap<AccountId, Supporter>,
    pub balance: u128,
    pub goal: u128,
    pub end_time: u64,
    pub status: ProjectStatus,
    pub plan: SupporterPlans,
    pub level_amounts: LookupMap<SupporterLevel, u128>,
}

#[near_bindgen]
#[derive(BorshDeserialize, BorshSerialize, PanicOnDefault)]
pub struct Nearkick {
    current_id: u64,
    projects: UnorderedMap<u64, Project>,
}

causes error[E0277]: the trait bound `Project: Serialize` is not satisfied, note: required by a bound in `near_sdk::serde_json::to_vec` error.

If I add Serialize and Deserialize to it like this:

#[near_bindgen]
#[derive(Serialize, Deserialize, BorshDeserialize, BorshSerialize, PanicOnDefault)]
#[serde(crate = "near_sdk::serde")]
pub struct Nearkick {
    current_id: u64,
    projects: UnorderedMap<u64, Project>,
}

I get this error error[E0277]: the trait bound `UnorderedMap<u64, Project>: Serialize` is not satisfied, note: required by `near_sdk::serde::ser::SerializeStruct::serialize_field`

Cargo.toml

[lib]
crate-type = ["cdylib"]

[dependencies]
near-sdk = "4.0.0-pre.2"

[profile.release]
codegen-units = 1
opt-level = "z"
lto = true
debug = false
panic = "abort"
overflow-checks = true

I tried adding Serialize and Deserialize to all of my structs and enums, but I still get the error.

What's the definition of `Project`? – Lambda Fairy Dec 30 '21 at 06:52 — Lambda Fairy, Dec 30 '21 at 06:52

Wabinab · Answer 1 · 2022-03-18T07:52:23.980

You have two methods:

First, use HashMap rather than UnorderedMap.
Second, according to How can I serialize a near-sdk-rs LookUpMap that uses a String as a key, or is there a better way? and https://www.near-sdk.io/contract-interface/serialization-interface#overriding-serialization-protocol-default, you add the #[result_serializer(borsh)] and/or the #[serializer(borsh)] where appropriate in the impl function that raises the error (check your Debugging info when compiling for which file and line it raises trait bound not satisfied error). You change the function, not the struct, in this case!

error[E0277]: the trait bound `Project: Serialize` is not satisfied, note: required by a bound in `near_sdk::serde_json::to_vec`

1 Answers1