`sqlx::Type` for Enum with String repr

[tisonkun]

Bug Description

Currently, postgres Type would always generate Type with PgTypeInfo::with_name(#ty_name) for enum.

While we are using sqlx::Type derive with Enum and the underline type is expected to be TEXT or VARCHAR, this can result in an error:

error returned from database: type "datatype" does not exist

I suppose we can suppress this generation or use TEXT with some config options.

Minimal Reproduction

#[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize, sqlx::Type)]
#[serde(rename_all = "snake_case")]
#[sqlx(rename_all = "snake_case")]
pub enum DataType {
    Int,
    UInt,
    Float,
    Binary,
    String,
    Boolean,
    Interval,
    Timestamp,
    Variant,

    Null,
}

And try to insert into a DB with column data_type TEXT.

Info

• SQLx version: 0.8.2
• SQLx features enabled: ["postgres", "runtime-tokio-rustls"]
• Database server and version: [REQUIRED] Postgres 16.3
• Operating system: macOS 13.4
• rustc --version: rustc 1.83.0-nightly (363ae4188 2024-09-24)

[tisonkun]

Straightforward, render type with TEXT if #[sqlx(type_name = "...")] is not specified, instead of default to ident's name.

[tisonkun]

Use #[sqlx(type_name = "TEXT")] seems can work it around.

[tisonkun]

I noticed the "the names of the variants are used" in https://docs.rs/sqlx/latest/sqlx/trait.Type.html#enumeration

Without, the names of the variants are used instead and expects a textual SQL type (e.g., VARCHAR, TEXT).

now.

So this can be a feature request rather than a bug.

[dns2utf8-novaziun]

The API in the trait is without a self reference limits enums to things that can be reduced to one type like "TEXT".

But forking sqlx for this change seems a bit much, so I hope the maintainers pickup this change

impl sqlx::Type<sqlx::Postgres> for TargetQuery {
    fn type_info() -> sqlx::postgres::PgTypeInfo { ... }
}

This would solve that problem:

impl sqlx::Type<sqlx::Postgres> for TargetQuery {
    fn type_info(&self) -> sqlx::postgres::PgTypeInfo {
        match self { ... }
    }
}