Merge pull request #272 from NLipatov/refactor/replace-errors-as-with-astype

refactor(errors): replace errors.As with errors.AsType where applicable

Author: NLipatov

src/domain/network/err_timeout_test.go

@@ -14,10 +14,8 @@ type netError interface {
 	Temporary() bool
 }
 
-var _ netError = ErrTimeout{cause: context.DeadlineExceeded}
-
 func TestErrTimeout_ErrorReturnsCauseMessage(t *testing.T) {
-	e := ErrTimeout{cause: context.DeadlineExceeded}
+	e := NewErrTimeout(context.DeadlineExceeded)
 	if e.Error() == "" {
 		t.Fatalf("Error() must return non-empty message")
 	}
@@ -28,7 +26,7 @@ func TestErrTimeout_ErrorReturnsCauseMessage(t *testing.T) {
 }
 
 func TestErrTimeout_UnwrapAndErrorsIs_As(t *testing.T) {
-	e := ErrTimeout{cause: context.DeadlineExceeded}
+	e := NewErrTimeout(context.DeadlineExceeded)
 
 	// Unwrap via errors.Is
 	if !errors.Is(e, context.DeadlineExceeded) {
@@ -40,10 +38,10 @@ func TestErrTimeout_UnwrapAndErrorsIs_As(t *testing.T) {
 		t.Fatalf("errors.Is must see cause through additional wrap")
 	}
 
-	// errors.As to our type
-	var et ErrTimeout
-	if !errors.As(e, &et) {
-		t.Fatalf("errors.As must match ErrTimeout")
+	// errors.AsType to our type
+	et, ok := errors.AsType[*ErrTimeout](e)
+	if !ok {
+		t.Fatalf("errors.AsType must match *ErrTimeout")
 	}
 	if !errors.Is(et.cause, context.DeadlineExceeded) {
 		t.Fatalf("As must preserve cause")
@@ -70,7 +68,7 @@ func TestNewErrTimeout(t *testing.T) {
 }
 
 func TestErrTimeout_TimeoutAndTemporaryFlags(t *testing.T) {
-	e := ErrTimeout{cause: context.DeadlineExceeded}
+	e := NewErrTimeout(context.DeadlineExceeded)
 
 	// Satisfies net.Error semantics
 	var ne netError = e

src/infrastructure/network/ws/adapter/adapter.go

@@ -212,8 +212,7 @@ func (a *Adapter) mapReadErr(err error) error {
 		return nil
 	}
 	// Map graceful WS close to io.EOF (as net.Conn Read would do).
-	var ce *websocket.CloseError
-	if errors.As(err, &ce) {
+	if ce, ok := errors.AsType[*websocket.CloseError](err); ok {
 		switch ce.Code {
 		case websocket.StatusNormalClosure, websocket.StatusGoingAway:
 			return io.EOF
@@ -235,8 +234,7 @@ func (a *Adapter) mapWriteErr(err error) error {
 	if err == nil {
 		return nil
 	}
-	var ce *websocket.CloseError
-	if errors.As(err, &ce) {
+	if _, ok := errors.AsType[*websocket.CloseError](err); ok {
 		// For writes after close, most net.Conn impls return net.ErrClosed.
 		return net.ErrClosed
 	}

src/infrastructure/network/ws/adapter/adapter_test.go

@@ -340,8 +340,15 @@ func TestAdapter_Read_FromExistingReader_ErrorMapped(t *testing.T) {
 	if n != 0 {
 		t.Fatalf("expected n=0 on second read, got %d", n)
 	}
-	var ne interface{ Timeout() bool }
-	if !errors.As(err, &ne) || !ne.Timeout() {
+	type errTimeout interface {
+		Timeout() bool
+		Error() string
+	}
+	errTO, ok := errors.AsType[errTimeout](err)
+	if !ok {
+		t.Fatalf("expected a timeout error; got %v", err)
+	}
+	if !errTO.Timeout() {
 		t.Fatalf("expected timeout net.Error, got %v", err)
 	}
 }

src/infrastructure/tunnel/dataplane/client/udp_chacha20/tun_handler.go

@@ -92,8 +92,7 @@ func (w *TunHandler) HandleTun() error {
 					if w.ctx.Err() != nil {
 						return nil
 					}
-					var netErr net.Error
-					if errors.As(err, &netErr) {
+					if _, ok := errors.AsType[net.Error](err); ok {
 						// Transient socket error (e.g. WSAENOBUFS) — packet lost, socket is fine.
 						log.Printf("transient write error (packet dropped): %v", err)
 						continue

src/presentation/mode_selection/args_app_mode_test.go

@@ -83,25 +83,22 @@ func TestArgsAppMode_Mode(t *testing.T) {
 				if tt.expectedErrMsg != "" && err.Error() != tt.expectedErrMsg {
 					t.Errorf("Mode() error message = %q, want %q", err.Error(), tt.expectedErrMsg)
 				}
-				// Check error type using errors.As
+				// Check error type using errors.AsType
 				if tt.expectedErrType != nil {
 					var noModeProvided mode.NoModeProvided
 					var invalidModeProvided mode.InvalidModeProvided
 					var invalidExecPathProvided mode.InvalidExecPathProvided
 					switch {
 					case errors.As(tt.expectedErrType, &noModeProvided):
-						var target mode.NoModeProvided
-						if !errors.As(err, &target) {
+						if _, ok := errors.AsType[mode.NoModeProvided](err); !ok {
 							t.Errorf("expected error type %T, got %T", tt.expectedErrType, err)
 						}
 					case errors.As(tt.expectedErrType, &invalidModeProvided):
-						var target mode.InvalidModeProvided
-						if !errors.As(err, &target) {
+						if _, ok := errors.AsType[mode.InvalidModeProvided](err); !ok {
 							t.Errorf("expected error type %T, got %T", tt.expectedErrType, err)
 						}
 					case errors.As(tt.expectedErrType, &invalidExecPathProvided):
-						var target mode.InvalidExecPathProvided
-						if !errors.As(err, &target) {
+						if _, ok := errors.AsType[mode.InvalidExecPathProvided](err); !ok {
 							t.Errorf("expected error type %T, got %T", tt.expectedErrType, err)
 						}
 					}