Derive FromRow with a Vec<> field

[rogerta]

Hi there,

It seems I can't derive FromRow for my struct because of a Vec<> field. My struct looks like this:

#[derive(Debug, Default, Deserialize, PartialEq, Serialize)]
pub struct App {
  ...
  #[sqlx(default)]
  pub clients: Vec<Client>,

I get the following compiler error at the App::from_row(&row) call site, see below. I thought the #[sqlx(default)] attribute would initialized the field to an empty vector. What am I missing? Thanks.

Compiler error:

423 |     match App::from_row(row) {
    |                ^^^^^^^^ function or associated item cannot be called on `App` due to unsatisfied trait bounds
    |
   ::: src/app.rs:85:1
    |
85  | pub struct App {
    | --------------
    | |
    | function or associated item `from_row` not found for this struct
    | doesn't satisfy `App: FromRow<'_, _>`
    |
   ::: /home/rogerta/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/vec/mod.rs:400:1
    |
400 | pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
    | ------------------------------------------------------------------------------------------------
    | |
    | doesn't satisfy `Vec<app::Client>: Type<_>`
    | doesn't satisfy `Vec<app::Client>: sqlx::Decode<'_, _>`
    |
    = note: the following trait bounds were not satisfied:
            `Vec<app::Client>: Type<_>`
            `Vec<app::Client>: sqlx::Decode<'_, _>`
    = note: the following trait bounds were not satisfied:
            `Vec<app::Client>: sqlx::Decode<'_, _>`
            which is required by `App: FromRow<'_, _>`
            `Vec<app::Client>: Type<_>`
            which is required by `App: FromRow<'_, _>`

[blackghost1987]

Are you sure this is a Rocket problem? The FromRow trait is defined by the sqlx crate. I think you should report this issue in https://github.com/launchbadge/sqlx
(Unless you think this is somehow caused by Rocket, but it does not look like it based on the compiler error)

[rogerta]

No I'm not sure. Rocket v0.5.0-rc.2 is still using sqlx v0.5.13, and the sqlx project is now at v0.6.2. So I thought folks here might have encountered this problem with this older version. Let me ask in the sqlx project, thanks.