Passing arg to bool flag breaks other flags

[svartkanin]

My urfave/cli version is

v2.27.4

Checklist

• Are you running the latest v2 release? The list of releases is here.
• Did you check the manual for your release? The v2 manual is here
• Did you perform a search about this problem? Here's the GitHub guide about searching.

Dependency Management

• My project is using go modules.

Describe the bug

Using a boolean flag with a argument does not terminate the command.

To reproduce

package main

import (
	"fmt"
	"log"
	"os"

	"github.com/urfave/cli/v2"
)

func main() {
	app := &cli.App{
		Flags: []cli.Flag{
			&cli.BoolFlag{
				Name: "bool",
			},
			&cli.StringFlag{
				Name: "text",
			},
		},
		Action: func(ctx *cli.Context) error {
			fmt.Println(ctx.String("bool"))
			fmt.Println(ctx.String("text"))
			return nil
		},
	}

	if err := app.Run(os.Args); err != nil {
		log.Fatal(err)
	}
}

Observed behavior

When a argument is passed to a bool flag then subsequent flags are not read correctly anymore

$ go run . --bool --text str
true
str

$ go run . --bool wrong --text str
true

Expected behavior

If a argument is passed to a bool flag then the command should fail as that is an invalid input

Run go version and paste its output here

go version go1.22.2 darwin/arm64

[dearchap]

@svartkanin The whole point of bool flags is to not pass an arg. Why are you passing an arg for the bool flag in the first place ?

[svartkanin]

@dearchap I'm aware of that, but if someone accidentally uses the flags this way there will be unintentional behaviour because the parsing is all messed up for the flags coming after as it does not terminate.
How would we verify that the flags were used as intended?

[dearchap]

It's not easy. What happens if 'wrong' is actually defined as a sub command ? We would then try to process it as such thinking that's what the user intended

[svartkanin]

If there is no subcommand defined with that name and the Args parameter is set to false for the given command this should result in a failure

[autowp]

Also issue with boolFlag in v3.0.0-alpha9:
--flag=false and --flag false is not the same. First parsed to false, but second to true

--flag=0 and --flag 0 too

[dearchap]

Its not really an issue. Its the design for command line flags in general. As per this https://pkg.go.dev/flag this is the standard format

-flag x  // non-boolean flags only

without that it becomes ambigious. We cannot intend user's intention here.