Inconsistent slice behavior, Value/Destination not applied

[erikwilson]

my urfave/cli version is

2.2.0
Also impacts 1.22.4

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.
• My project is using vendoring.

Describe the bug

Slice flags are missing a Destination part (except for StringSliceFlag), but when used with altsrc the values are not propagated.

To reproduce

code:

package main

import (
	"fmt"
	"os"

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

func main() {
	var (
		testInt         int
		testIntSlice    cli.IntSlice
		testStringSlice cli.StringSlice
	)

	flags := []cli.Flag{
		altsrc.NewIntFlag(&cli.IntFlag{
			Name:        "test-int",
			Aliases:     []string{"t"},
			Destination: &testInt,
		}),
		altsrc.NewIntSliceFlag(&cli.IntSliceFlag{
			Name:    "test-int-slice",
			Aliases: []string{"i"},
			Value:   &testIntSlice,
		}),
		altsrc.NewStringSliceFlag(&cli.StringSliceFlag{
			Name:        "test-string-slice",
			Aliases:     []string{"s"},
			Destination: &testStringSlice,
		}),
		&cli.StringFlag{Name: "load"},
	}

	app := &cli.App{
		Action: func(c *cli.Context) error {
			fmt.Printf("Have test-int value: %v\n", testInt)
			fmt.Printf("Have test-int context: %v\n", c.Int("test-int"))
			fmt.Printf("Have test-int-slice value: %v\n", testIntSlice.Value())
			fmt.Printf("Have test-int-slice context: %v\n", c.IntSlice("test-int-slice"))
			fmt.Printf("Have test-string-slice value: %v\n", testStringSlice.Value())
			fmt.Printf("Have test-string-slice context: %v\n", c.StringSlice("test-string-slice"))
			return nil
		},
		Before: altsrc.InitInputSourceWithContext(flags, altsrc.NewYamlSourceFromFlagFunc("load")),
		Flags:  flags,
	}

	app.Run(os.Args)
}

config yaml:

test-int: 1
test-int-slice: [ 1, 2, 3 ]
test-string-slice: [ a, b, c ]

Observed behavior

GO111MODULE=on go run test.go --load conf 
Have test-int value: 1
Have test-int context: 1
Have test-int-slice value: []
Have test-int-slice context: [1 2 3]
Have test-string-slice value: []
Have test-string-slice context: [a b c]

GO111MODULE=on go run test.go --load conf -t 3 -i 7 -i 8 -i 9 -s a -s z
Have test-int value: 3
Have test-int context: 3
Have test-int-slice value: [7 8 9]
Have test-int-slice context: [7 8 9]
Have test-string-slice value: [a z]
Have test-string-slice context: [a z]

Expected behavior

GO111MODULE=on go run test.go --load conf 
Have test-int value: 1
Have test-int context: 1
Have test-int-slice value: [? ? ?]
Have test-int-slice context: [1 2 3]
Have test-string-slice value: [a b c]
Have test-string-slice context: [a b c]

Additional context

Possibly related issues: #1121, #1075

[stale]

This issue or PR has been automatically marked as stale because it has not had recent activity. Please add a comment bumping this if you're still interested in it's resolution! Thanks for your help, please let us know if you need anything else.

[stale]

Closing this as it has become stale.

[meatballhat]

@erikwilson Belated thank you for the lovely issue! I'm working on a fix now 👍🏼

[dearchap]

See PR#1495

[dearchap]

Fixed in latest release.