sqlitex.Pool.Get should never return a nil Conn — click here to learn more!

[peterbourgon]

Right now, sqlitex.Pool.Get can return a nil Conn in a few circumstances, for example if the pool has been closed, or if the provided context has been canceled. This means consumers can't safely use the normal Get/defer Put idiom.

conn := pool.Get(ctx)
defer pool.Put(conn)
// use conn

And instead must do an explicit nil check within each stanza.

conn := pool.Get(ctx)
if conn == nil {
    // return
}
defer pool.Put(conn)
// use conn

It would be better if the Get method always returned a non-nil Conn, and, in the situations where it's not actually usable, have all of its methods short-circuit and return an appropriate error.

[zombiezen]

This API is carried over from `crawshaw.io/sqlite/sqlitex`, so I'm a bit loathe to change the nil-ness of the return, but I'd be open to having a nil `*sqlite.Conn` return errors. Would that address your needs?

[peterbourgon]

I'd be open to having a nil *sqlite.Conn return errors. Would that address your needs?

Ah, you mean if all the methods did a nil check on the receiver? Yeah, Totes McGotes 👍 And if pool.Put &c. handled a nil Conn, too.

[peterbourgon]

@zombiezen Does that cover sqlitex.Exec-class functions?

edit: I reckon it does, just want the explicit confirmation :)

[zombiezen]

It should, since all of the sqlitex.Exec methods are implemented in terms of methods on *sqlite.Conn. I haven't tested too extensively, so if it doesn't cover it, feel free to reopen.

[peterbourgon]

conn := pool.Get(ctx)
defer pool.Put(conn)

This still panics if conn is nil.

[peterbourgon]

I can't seem to re-open? lol github

@zombiezen ← mentioning just in case

[zombiezen]

Oh right, Pool.Put needed to be changed. 🤦 I'll have a fix today.