Is there a way we can use an executor multiple times in a function?

[frederikhors]

Using sqlx 0.6.2 (latest today 2023/01/13) is there a way we can make the below code to work?

pub async fn try_this(
    connection: impl sqlx::PgExecutor<'_>,
) {
    connection.execute("select 1").await?;

    connection.execute("select 2").await?;
}

The error:

error[E0382]: use of moved value: `connection`
    |
594 |         connection: impl sqlx::PgExecutor<'_>,
    |         ---------- move occurs because `connection` has type `impl sqlx::PgExecutor<'_>`, which does not implement the `Copy` trait
...
598 |         connection.execute("select 1").await?;
    |                    ------------------- `connection` moved due to this method call
599 |
600 |         connection.execute("select 2").await?;
    |         ^^^^^^^^^^ value used here after move
    |
note: this function takes ownership of the receiver `self`, which moves `connection`
   --> C:\Users\Fred\.cargo\registry\src\github.com-1ecc6299db9ec823\sqlx-core-0.6.2\src\executor.rs:30:9
    |
30  |         self,
    |         ^^^^
help: consider further restricting this bound
    |
594 |         connection: impl sqlx::PgExecutor<'_> + std::marker::Copy,
    |                                               +++++++++++++++++++

[VersBinarii]

Not sure about your example but maybe consider passing in impl Connection and begin transaction to execute multiple queries

[frederikhors]

in this case you should be able to do it as:

pub async fn try_this(
    connection: &Transaction<...>,
) {
    query("SELECT 1").fetch_one(connection).await;
    query("SELECT 1").fetch_one(conneciton).await;
}

Yeah, but this method sometimes is called with a Transaction, sometimes with a direct connection from pool. Hence the impl sqlx::PgExecutor<'_>.

[VersBinarii]

But both PgConnection and Transaction implement Executor trait.
So this should work:

pub async fn try_this(
    connection: &impl PgExecutor<...>,
) {
    query("SELECT 1").fetch_one(connection).await;
    query("SELECT 1").fetch_one(connection).await;
}

[frederikhors]

Thank you for the help.

If I use this code:

pub async fn try_this(
  connection: &impl sqlx::PgExecutor<'_>,
) {
  connection.execute("select 1").await?;

  connection.execute("select 2").await?;

  sqlx::query_as::<_, Self>("select 1").fetch_one(connection).await?;
}

the error is:

error[E0277]: the trait bound `&impl sqlx::PgExecutor<'_>: sqlx::Executor<'_>` is not satisfied
    |
604 |             .fetch_one(connection)
    |              --------- ^^^^^^^^^^ the trait `sqlx::Executor<'_>` is not implemented for `&impl sqlx::PgExecutor<'_>`
    |              |
    |              required by a bound introduced by this call
    |
note: required by a bound in `sqlx::query::QueryAs::<'q, DB, O, A>::fetch_one`
   --> C:\Users\Fred\.cargo\registry\src\github.com-1ecc6299db9ec823\sqlx-core-0.6.2\src\query_as.rs:140:17
    |
140 |         E: 'e + Executor<'c, Database = DB>,
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `sqlx::query::QueryAs::<'q, DB, O, A>::fetch_one`

[VersBinarii]

Sorry, then i'm not sure 😞
Last think you could maybe try is to have it as

pub async fn try_this(
  connection: &mut sqlx::PgConnection,
) {
  sqlx::query_as::<_, Self>("select 1").fetch_one(connection).await?;
}

and see if the compiler will coerce Transaction into PgConnection

[frederikhors]

Yeah. This works. I just found it in another issue. Wow. Thanks. I was writing here just now! :)