Add support for NamedValueChecker interface (#1125)

Added in 1.9: https://go.dev/doc/go1.9#minor_library_changes.

conn_go19.go

@@ -0,0 +1,35 @@
+//go:build go1.9
+// +build go1.9
+
+package pq
+
+import (
+	"database/sql/driver"
+	"reflect"
+)
+
+var _ driver.NamedValueChecker = (*conn)(nil)
+
+func (c *conn) CheckNamedValue(nv *driver.NamedValue) error {
+	if _, ok := nv.Value.(driver.Valuer); ok {
+		// Ignore Valuer, for backward compatibility with pq.Array().
+		return driver.ErrSkip
+	}
+
+	// Ignoring []byte / []uint8.
+	if _, ok := nv.Value.([]uint8); ok {
+		return driver.ErrSkip
+	}
+
+	v := reflect.ValueOf(nv.Value)
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+	if v.Kind() == reflect.Slice {
+		var err error
+		nv.Value, err = Array(v.Interface()).Value()
+		return err
+	}
+
+	return driver.ErrSkip
+}

conn_go19_test.go

@@ -0,0 +1,83 @@
+//go:build go1.9
+// +build go1.9
+
+package pq
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestArrayArg(t *testing.T) {
+	db := openTestConn(t)
+	defer db.Close()
+
+	for _, tc := range []struct {
+		pgType  string
+		in, out interface{}
+	}{
+		{
+			pgType: "int[]",
+			in:     []int{245, 231},
+			out:    []int64{245, 231},
+		},
+		{
+			pgType: "int[]",
+			in:     &[]int{245, 231},
+			out:    []int64{245, 231},
+		},
+		{
+			pgType: "int[]",
+			in:     []int64{245, 231},
+		},
+		{
+			pgType: "int[]",
+			in:     &[]int64{245, 231},
+			out:    []int64{245, 231},
+		},
+		{
+			pgType: "varchar[]",
+			in:     []string{"hello", "world"},
+		},
+		{
+			pgType: "varchar[]",
+			in:     &[]string{"hello", "world"},
+			out:    []string{"hello", "world"},
+		},
+	} {
+		if tc.out == nil {
+			tc.out = tc.in
+		}
+		t.Run(fmt.Sprintf("%#v", tc.in), func(t *testing.T) {
+			r, err := db.Query(fmt.Sprintf("SELECT $1::%s", tc.pgType), tc.in)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer r.Close()
+
+			if !r.Next() {
+				if r.Err() != nil {
+					t.Fatal(r.Err())
+				}
+				t.Fatal("expected row")
+			}
+
+			defer func() {
+				if r.Next() {
+					t.Fatal("unexpected row")
+				}
+			}()
+
+			got := reflect.New(reflect.TypeOf(tc.out))
+			if err := r.Scan(Array(got.Interface())); err != nil {
+				t.Fatal(err)
+			}
+
+			if !reflect.DeepEqual(tc.out, got.Elem().Interface()) {
+				t.Errorf("got %v, want %v", got, tc.out)
+			}
+		})
+	}
+
+}