StringSliceFlag does not set destination when reading from yaml

[lburgazzoli]

my urfave/cli version is

( v2.2.0 )

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.
• My project is automatically downloading the latest version.
• I am unsure of what my dependency management setup is.

Describe the bug

The Destination field of a StringSliceFlag is not set when reading from a YAML file

To reproduce

Create YAML file with the following content:

dependency:
  - mvn:g/a/v

Create a Go application with the following code:

package main

import (
	"fmt"
	"log"
	"os"

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

func main() {
	dependencies := &cli.StringSlice{}

	flags := []cli.Flag{
		altsrc.NewStringFlag(&cli.StringFlag{
			Name:  "config",
			Value: ".app-config.yaml",
		}),
		altsrc.NewStringSliceFlag(&cli.StringSliceFlag{
			Name:        "dependency",
			Usage:       "dependency",
			Aliases:     []string{"d"},
			Destination: dependencies,
		}),
	}
	app := &cli.App{
		Name:   "kamel",
		Usage:  "kamel",
		Before: altsrc.InitInputSourceWithContext(flags, altsrc.NewYamlSourceFromFlagFunc("config")),
		Flags:  flags,
		Action: func(c *cli.Context) error {
			fmt.Println("context:", c.StringSlice("dependency"))
			fmt.Println("destination:", dependencies)
			return nil
		},
	}

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

Observed behavior

This code will print:

context: [mvn:g/a/v]
destination: []

Expected behavior

the value read from the file and associated to the dependency flag should be available both via the context and the destination.

Run go version and paste its output here

go version go1.14.9 linux/amd64

Run go env and paste its output here

GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/lburgazz/.cache/go-build"
GOENV="/home/lburgazz/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/lburgazz/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/opt/data/sfw/lang/go/1.14.9"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/opt/data/sfw/lang/go/1.14.9/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/lburgazz/work/lb/dev/camel-k-cli/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build629793049=/tmp/go-build -gno-record-gcc-switches"

[mikunalpha]

Trick?

[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.

[dearchap]

@lburgazzoli I have a draft PR which fixes this issue if you are interested in testing out. Thanks

[dearchap]

Fixed. Please use latest release