[xerrors] implement IsTimeout helper function (#7)

go.work

@@ -1,6 +1,7 @@
-go 1.22.2
+go 1.23.4
 
 use (
+	./xerrors
 	./xmaps
 	./xmath
 	./xnet/xhttp

xerrors/errors.go

@@ -0,0 +1,21 @@
+package xerrors
+
+import (
+	"errors"
+)
+
+// IsTimeout reports whether the provided error indicates a timeout condition.
+func IsTimeout(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	e, ok := err.(interface{ Timeout() bool })
+	if ok && e.Timeout() {
+		return true
+	}
+
+	inner := errors.Unwrap(err)
+
+	return inner != nil && IsTimeout(inner)
+}

xerrors/errors_test.go

@@ -0,0 +1,35 @@
+package xerrors_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/kucherenkovova/gopypaste/xerrors"
+)
+
+type customTimeoutError struct{}
+
+func (e customTimeoutError) Error() string { return "timeout" }
+
+func (e customTimeoutError) Timeout() bool { return true }
+
+func TestIsTimeout(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+		want bool
+	}{
+		{name: "nil", err: nil, want: false},
+		{name: "context timeout", err: context.DeadlineExceeded, want: true},
+		{name: "wrapped context timeout", err: fmt.Errorf("bad stuff: %w", context.DeadlineExceeded), want: true},
+		{name: "custom timeout", err: customTimeoutError{}, want: true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := xerrors.IsTimeout(tt.err); got != tt.want {
+				t.Errorf("IsTimeout() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

xerrors/go.mod

@@ -0,0 +1,3 @@
+module github.com/kucherenkovova/gopypaste/xerrors
+
+go 1.23.4