Fix:(issue_2238) Dont process flags for completion command

command.go

@@ -161,6 +161,8 @@ type Command struct {
 	globaHelpFlagAdded bool
 	// whether global version flag was added
 	globaVersionFlagAdded bool
+	// whether this is a completion command
+	isCompletionCommand bool
 }
 
 // FullName returns the full name of the command.

command_run.go

@@ -140,13 +140,20 @@ func (cmd *Command) run(ctx context.Context, osArgs []string) (_ context.Context
 	}
 
 	var rargs Args = &stringSliceArgs{v: osArgs}
+	var args Args = &stringSliceArgs{rargs.Tail()}
+
+	if cmd.isCompletionCommand {
+		tracef("completion command detected, skipping pre-parse (cmd=%[1]q)", cmd.Name)
+		cmd.parsedArgs = args
+		return ctx, cmd.Action(ctx, cmd)
+	}
+
 	for _, f := range cmd.allFlags() {
 		if err := f.PreParse(); err != nil {
 			return ctx, err
 		}
 	}
 
-	var args Args = &stringSliceArgs{rargs.Tail()}
 	var err error
 
 	if cmd.SkipFlagParsing {

completion.go

@@ -65,6 +65,7 @@ func buildCompletionCommand(appName string) *Command {
 		Action: func(ctx context.Context, cmd *Command) error {
 			return printShellCompletion(ctx, cmd, appName)
 		},
+		isCompletionCommand: true,
 	}
 }
 

completion_test.go

@@ -20,6 +20,12 @@ func TestCompletionDisable(t *testing.T) {
 func TestCompletionEnable(t *testing.T) {
 	cmd := &Command{
 		EnableShellCompletion: true,
+		Flags: []Flag{
+			&BoolFlag{
+				Name:     "goo",
+				Required: true,
+			},
+		},
 	}
 
 	err := cmd.Run(buildTestContext(t), []string{"foo", completionCommandName})