cannot use db (variable of type *pgxpool.Pool) as pgxscan.Querier value in argument to pgxscan.Select: *pgxpool.Pool does not implement pgxscan.Querier (wrong type for method Query)

[edewindt]

package data

import (
    "context"
    "log"
    "os"

    "github.com/georgysavva/scany/pgxscan"
    "github.com/jackc/pgx/v5/pgxpool"
)

var dburl = os.Getenv("PG_URI")

var ctx = context.Background()

var db, _ = pgxpool.New(ctx, dburl)

type HTTPError struct {
    Status  string
    Message string
}

type Hello struct {
    ID    int    `json:"id"`
    Hello string `json:"hello"`
}

func HelloFunc(id string) []*Hello {
    var hellos []*Hello
    defer func() {
        if err := recover(); err != nil {
            log.Println("panic occurred:", err)
        }
    }()
    pgxscan.Select(ctx, db, &hellos, `SELECT * from hello WHERE id = $1`, id)

    return hellos

}

db is erroring with:cannot use db (variable of type pgxpool.Pool) as pgxscan.Querier value in argument to pgxscan.Select: pgxpool.Pool does not implement pgxscan.Querier (wrong type for method Query)

[Xamss]

The same issue here but it should be fine as long as you use module jackc/pgx version 4 instead of version 5

[edewindt]

func QueryAndScan(ctx context.Context, query string, dest interface{}, args ...interface{}) error {
    rows, err := db.Query(ctx, query, args...)
    if err != nil {
        return err
    }
    defer rows.Close()

    sliceVal := reflect.ValueOf(dest)
    if sliceVal.Kind() != reflect.Ptr || sliceVal.Elem().Kind() != reflect.Slice {
        return errors.New("dest must be a pointer to a slice")
    }

    sliceElemType := sliceVal.Elem().Type().Elem()
    isPointer := sliceElemType.Kind() == reflect.Ptr
    if isPointer {
        sliceElemType = sliceElemType.Elem() // Get the type that the pointer points to
    }
    if sliceElemType.Kind() != reflect.Struct {
        return errors.New("slice elements must be structs or pointers to structs")
    }

    for rows.Next() {
        var elem reflect.Value
        if isPointer {
            elem = reflect.New(sliceElemType)
        } else {
            elem = reflect.New(sliceElemType).Elem()
        }

        fields := make([]interface{}, elem.Elem().NumField())
        for i := range fields {
            fields[i] = elem.Elem().Field(i).Addr().Interface()
        }

        err := rows.Scan(fields...)
        if err != nil {
            log.Println("Error scanning row:", err)
            continue
        }

        if isPointer {
            sliceVal.Elem().Set(reflect.Append(sliceVal.Elem(), elem))
        } else {
            sliceVal.Elem().Set(reflect.Append(sliceVal.Elem(), elem.Elem()))
        }
    }

    if err := rows.Err(); err != nil {
        return err
    }

    return nil
}

I've been using this as a replacement until it gets patched

[edewindt]

Also assume that db is a *pgxpool.Pool type

[georgysavva]

@edewindt @Xamss to use "github.com/jackc/pgx/v5" you need to use "scany/v2".

This is also true:

The same issue here but it should be fine as long as you use module jackc/pgx version 4 instead of version 5

[georgysavva]

Feel free to reopen if it doesn't solve your problem