sqlx::any::AnyTypeInfoKind is private, cannot implement Type<Any>

[rnza0u]

Bug Description

Hello !

When using the Any driver, we run into some issues when creating custom decoders.

#[derive(sqlx::Type)] only generate Decode implementations for specific drivers (Type<Postgres>, Type<Sqlite>, Decode<Postgres>, Decode<Sqlite> etc...). It does not generate implementations for the Any driver.

Implementing a custom Decode can be done for the Any driver. However, it seems like it is impossible to write a Type implementation since there are no ways to return a AnyTypeInfo from outside the sqlx crate.

The reason is that sqlx::any::AnyTypeInfoKind is not exported within the library.

Is there a workaround that ?

Thank you...

Info

• SQLx version: 0.8.2
• SQLx features enabled: ["tls-rustls", "runtime-tokio", "postgres", "sqlite", "uuid", "chrono"]
• Database server and version: Sqlite and postgres
• Operating system: Linux
• rustc --version: 1.81.0

[abonander]

You can forward to an existing impl. That is the intent, and is what the derives do.

[rnza0u]

Thank a lot. I just tried it, and it works indeed !

Here is an implementation of a Decoder for chrono::DateTime that would work with the Any driver.

At runtime, it works for SQLite, i haven't tried with other DBMS so be careful !

The encoding of the date objects when inserting/updating rows is done with chrono::DateTime::to_rfc3339.

pub struct StoredDateTime(DateTime<Utc>);

impl StoredDateTime {
    pub fn unwrap(self) -> DateTime<Utc> {
        self.0
    }
}

impl<'r, DB: sqlx::Database> Decode<'r, DB> for StoredDateTime
where
    &'r str: Decode<'r, DB>,
{
    fn decode(
        value: <DB as sqlx::Database>::ValueRef<'r>,
    ) -> std::result::Result<Self, BoxDynError> {
        let value = <&str as Decode<DB>>::decode(value)?;
        Ok(StoredDateTime(
            DateTime::parse_from_rfc3339(value)?.to_utc(),
        ))
    }
}

impl<'r, DB: sqlx::Database> sqlx::Type<DB> for StoredDateTime
where
    &'r str: sqlx::Type<DB>,
{
    fn type_info() -> DB::TypeInfo {
        <&str as sqlx::Type<DB>>::type_info()
    }
}

Do you think that would be a valid approach ?