Replace QueryFunc with ForEachScannedRow

rows_test.go

@@ -2,9 +2,14 @@ package pgx_test
 
 import (
 	"context"
+	"errors"
+	"fmt"
+	"os"
 	"testing"
 
 	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/jackc/pgx/v5/pgxtest"
 	"github.com/stretchr/testify/require"
 )
 
@@ -28,3 +33,98 @@ func TestRowScanner(t *testing.T) {
 		require.Equal(t, int32(72), s.age)
 	})
 }
+
+func TestForEachScannedRow(t *testing.T) {
+	t.Parallel()
+
+	pgxtest.RunWithQueryExecModes(context.Background(), t, defaultConnTestRunner, nil, func(ctx context.Context, t testing.TB, conn *pgx.Conn) {
+		var actualResults []any
+
+		rows, _ := conn.Query(
+			context.Background(),
+			"select n, n * 2 from generate_series(1, $1) n",
+			3,
+		)
+		var a, b int
+		ct, err := pgx.ForEachScannedRow(rows, []any{&a, &b}, func() error {
+			actualResults = append(actualResults, []any{a, b})
+			return nil
+		})
+		require.NoError(t, err)
+
+		expectedResults := []any{
+			[]any{1, 2},
+			[]any{2, 4},
+			[]any{3, 6},
+		}
+		require.Equal(t, expectedResults, actualResults)
+		require.EqualValues(t, 3, ct.RowsAffected())
+	})
+}
+
+func TestForEachScannedRowScanError(t *testing.T) {
+	t.Parallel()
+
+	pgxtest.RunWithQueryExecModes(context.Background(), t, defaultConnTestRunner, nil, func(ctx context.Context, t testing.TB, conn *pgx.Conn) {
+		var actualResults []any
+
+		rows, _ := conn.Query(
+			context.Background(),
+			"select 'foo', 'bar' from generate_series(1, $1) n",
+			3,
+		)
+		var a, b int
+		ct, err := pgx.ForEachScannedRow(rows, []any{&a, &b}, func() error {
+			actualResults = append(actualResults, []any{a, b})
+			return nil
+		})
+		require.EqualError(t, err, "can't scan into dest[0]: cannot scan OID 25 in text format into *int")
+		require.Equal(t, pgconn.CommandTag{}, ct)
+	})
+}
+
+func TestForEachScannedRowAbort(t *testing.T) {
+	t.Parallel()
+
+	pgxtest.RunWithQueryExecModes(context.Background(), t, defaultConnTestRunner, nil, func(ctx context.Context, t testing.TB, conn *pgx.Conn) {
+		rows, _ := conn.Query(
+			context.Background(),
+			"select n, n * 2 from generate_series(1, $1) n",
+			3,
+		)
+		var a, b int
+		ct, err := pgx.ForEachScannedRow(rows, []any{&a, &b}, func() error {
+			return errors.New("abort")
+		})
+		require.EqualError(t, err, "abort")
+		require.Equal(t, pgconn.CommandTag{}, ct)
+	})
+}
+
+func ExampleForEachScannedRow() {
+	conn, err := pgx.Connect(context.Background(), os.Getenv("PGX_TEST_DATABASE"))
+	if err != nil {
+		fmt.Printf("Unable to establish connection: %v", err)
+		return
+	}
+
+	rows, _ := conn.Query(
+		context.Background(),
+		"select n, n * 2 from generate_series(1, $1) n",
+		3,
+	)
+	var a, b int
+	_, err = pgx.ForEachScannedRow(rows, []any{&a, &b}, func() error {
+		fmt.Printf("%v, %v\n", a, b)
+		return nil
+	})
+	if err != nil {
+		fmt.Printf("ForEachScannedRow error: %v", err)
+		return
+	}
+
+	// Output:
+	// 1, 2
+	// 2, 4
+	// 3, 6
+}