v3: can't reuse command with flags

[qwerty287]

Checklist

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Since a few alpha versions (started at least with alpha9.1), it seems to be no longer possible to reuse a command if you have a default on a flag. If you set the flag value once, it will be set to all following executions as well, even though it should use the default value if the flag is not specified.

To reproduce, check out this:

package main

import (
	"fmt"
	"log"
	"context"

	"github.com/urfave/cli/v3"
)

func main() {
	cmd := &cli.Command{
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name:  "lang",
				Value: "english",
				Usage: "language for the greeting",
			},
		},
		Action: func(ctx context.Context, cmd *cli.Command) error {
			fmt.Println(cmd.String("lang"))
			return nil
		},
	}

        // should output "y"
	if err := cmd.Run(context.Background(), []string{"x", "--lang", "y"}); err != nil {
		log.Fatal(err)
	}
	
        // should output "english", but outputs "y"
	if err := cmd.Run(context.Background(), []string{"x"}); err != nil {
		log.Fatal(err)
	}
}

This might sound like a really special usecase, but we reuse commands in our testing.

[dearchap]

@qwerty287 This is the expected behavior. If it was working previously it was due to a bug. Note that the Flag Value will never be changed

import (
	"fmt"
	"log"
	"context"

	"github.com/urfave/cli/v3"
)

func main() {
        ssf := &cli.StringFlag{
				Name:  "lang",
				Value: "english",
				Usage: "language for the greeting",
		}
	cmd := &cli.Command{
		Flags: []cli.Flag{
                    ssf,
		},
		Action: func(ctx context.Context, cmd *cli.Command) error {
			fmt.Println(cmd.String("lang"))
                        fmt.Println(ssf.Value)
			return nil
		},
	}

        // will output "y" and "english"
	if err := cmd.Run(context.Background(), []string{"x", "--lang", "y"}); err != nil {
		log.Fatal(err)
	}
	
        // will output "y" and "english"
	if err := cmd.Run(context.Background(), []string{"x"}); err != nil {
		log.Fatal(err)
	}
}

if you want to preserve you command state between runs you need to build a command tree as

import (
	"context"
	"fmt"
	"log"

	"github.com/urfave/cli/v3"
)

func buildCommand() *cli.Command {
	return &cli.Command{
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name:  "lang",
				Value: "english",
				Usage: "language for the greeting",
			},
		},
		Action: func(ctx context.Context, cmd *cli.Command) error {
			fmt.Println(cmd.String("lang"))
			return nil
		},
	}

}

func main() {

	cmd := buildCommand()

	// will output "y"
	if err := cmd.Run(context.Background(), []string{"x", "--lang", "y"}); err != nil {
		log.Fatal(err)
	}

	cmd = buildCommand()

	// will output "english"
	if err := cmd.Run(context.Background(), []string{"x"}); err != nil {
		log.Fatal(err)
	}
}

[qwerty287]

Thanks for the explanation. Will close this then