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What problem does this solve?

I've had several cases where I've made a typo when accessing a flag value via the context.

Solution description

I'd like the library to panic if I access an undefined flag.

func main() {
	app := &cli.App{
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name: "foo",
			},
		},
		Action: func(c *cli.Context) error {
		
			// I want this to panic
			_ = c.String("bar")
			return nil
		},
	}
	app.Run([]string{"test"})
}