feat: add regexp error for handle in app

internal/integration/all_of_test.go

@@ -6,9 +6,11 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/go-faster/errors"
 	"github.com/stretchr/testify/require"
 
 	api "github.com/ogen-go/ogen/internal/integration/test_allof"
+	"github.com/ogen-go/ogen/validate"
 )
 
 type allofTestServer struct {
@@ -51,10 +53,12 @@ func TestAllof(t *testing.T) {
 	ctx := context.Background()
 	t.Run("nullableStrings", func(t *testing.T) {
 		err := client.NullableStrings(ctx, api.NilString{})
-		require.EqualError(t, err, "validate: string: no regex match")
+		_, ok := errors.Into[*validate.NoRegexMatchError](err)
+		require.True(t, ok, "validate: string: no regex match")
 
 		err = client.NullableStrings(ctx, api.NewNilString("foo"))
-		require.EqualError(t, err, "validate: string: no regex match")
+		_, ok = errors.Into[*validate.NoRegexMatchError](err)
+		require.True(t, ok, "validate: string: no regex match")
 
 		err = client.NullableStrings(ctx, api.NewNilString("127.0.0.1"))
 		require.NoError(t, err)

validate/error.go → validate/errors.go

@@ -100,3 +100,11 @@ type MaxLengthError struct {
 func (e *MaxLengthError) Error() string {
 	return fmt.Sprintf("len %d greater than maximum %d", e.Len, e.MaxLength)
 }
+
+// NoRegexMatchError reports that value have no regexp match.
+type NoRegexMatchError struct{}
+
+// MaxLengthError implements error.
+func (*NoRegexMatchError) Error() string {
+	return "no regex match"
+}

validate/string.go

@@ -124,7 +124,7 @@ func (t String) Validate(v string) error {
 			return errors.Wrap(err, "execute regex")
 		}
 		if !match {
-			return errors.New("no regex match")
+			return &NoRegexMatchError{}
 		}
 	}
 	return nil