feat(cli): add typed error handling, remove IsCommandErr

Add error types for CLI commands:
- ErrSilent: command already printed error, exit 1 silently
- ErrCancel: user cancelled (ctrl-c), exit 0
- FlagError: bad flags/args, print error + usage
- HandleError(err): helper that handles all types

Remove commander.IsCommandErr which used fragile string matching.

Usage:
  if err := rootCmd.Execute(); err != nil {
      cli.HandleError(err)
  }

Author: ravisuhag

cli/commander/manager.go

@@ -1,10 +1,6 @@
 package commander
 
-import (
-	"strings"
-
-	"github.com/spf13/cobra"
-)
+import "github.com/spf13/cobra"
 
 // Manager manages and configures features for a CLI tool.
 type Manager struct {
@@ -106,27 +102,3 @@ func WithHooks(hooks []HookBehavior) func(*Manager) {
 		m.Hooks = hooks
 	}
 }
-
-// IsCommandErr checks if the given error is related to a Cobra command error.
-// This is useful for distinguishing between user errors (e.g., incorrect commands or flags)
-// and program errors, allowing the application to display appropriate messages.
-func IsCommandErr(err error) bool {
-	if err == nil {
-		return false
-	}
-
-	// Known Cobra command error keywords
-	cmdErrorKeywords := []string{
-		"unknown command",
-		"unknown flag",
-		"unknown shorthand flag",
-	}
-
-	errMessage := err.Error()
-	for _, keyword := range cmdErrorKeywords {
-		if strings.Contains(errMessage, keyword) {
-			return true
-		}
-	}
-	return false
-}

cli/error.go

@@ -0,0 +1,50 @@
+package cli
+
+import (
+	"errors"
+	"fmt"
+	"os"
+)
+
+// ErrSilent indicates the command already printed its error.
+// The error handler should exit 1 without printing anything.
+var ErrSilent = errors.New("silent error")
+
+// ErrCancel indicates the user cancelled the operation (e.g. ctrl-c).
+// The error handler should exit 0.
+var ErrCancel = errors.New("cancelled")
+
+// FlagError wraps an error caused by bad flags or arguments.
+// The error handler should print the error and show usage.
+type FlagError struct {
+	Err error
+}
+
+func (e *FlagError) Error() string { return e.Err.Error() }
+func (e *FlagError) Unwrap() error { return e.Err }
+
+// NewFlagError creates a FlagError.
+func NewFlagError(err error) *FlagError {
+	return &FlagError{Err: err}
+}
+
+// HandleError handles a command error by type.
+// FlagError prints the error (usage is shown by cobra).
+// SilentError exits without printing.
+// CancelError exits with code 0.
+// Other errors print "Error: <message>".
+func HandleError(err error) {
+	if err == nil {
+		return
+	}
+
+	switch {
+	case errors.Is(err, ErrCancel):
+		os.Exit(0)
+	case errors.Is(err, ErrSilent):
+		os.Exit(1)
+	default:
+		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
+		os.Exit(1)
+	}
+}