Exec method does not support queries that return results

[nalgeon]

Some sqlite pragmas return a value. For example, mmap_size (running in sqlite shell):

sqlite> pragma mmap_size=1024;
1024

The libsql driver's Exec method fails with an "Execute returned rows" for such pragmas. In fact, it fails for any query that returns a value (such as select 42).

I would argue that this is not an expected behavior. It's perfectly normal for an Exec query to return a value. Other drivers (such as mattn/go-sqlite3 and modernc.org/sqlite) allow this.

Code to reproduce:

package main

import (
	"database/sql"
	"fmt"
	"log"

	_ "github.com/tursodatabase/go-libsql"
)

func main() {
	db, err := sql.Open("libsql", "file:data.db")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	// You can replace the query with `select 42` to get the same error.
	res, err := db.Exec(`pragma mmap_size=1024`)
	fmt.Println("res", res)
	fmt.Println("err", err)
}

Result:

res <nil>
err failed to execute query pragma mmap_size=1024
error code = 2: Error executing statement: Execute returned rows