Alternate input sources YAML doesn't work when flag includes alternate name

[wcwynn]

Alternate names are described here: https://github.com/urfave/cli#alternate-names
Support for YAML is described here: https://github.com/urfave/cli#values-from-alternate-input-sources-yaml-toml-and-others

When any alternate source flag includes an alternate name, the alternate source input doesn't function as it should (i.e. it doesn't use the alternate input source data).

Code to reproduce:

package main

import (
    "fmt"
    "os"

    "github.com/urfave/cli/altsrc"
    "gopkg.in/urfave/cli.v1"
)

func main() {
    app := cli.NewApp()

    flags := []cli.Flag{
        /*  
            // OK
            altsrc.NewIntFlag(cli.IntFlag{Name: "test", Value: -1}),
            altsrc.NewStringFlag(cli.StringFlag{Name: "flag", Value: "default"}),
        */

        // NG #1
        altsrc.NewIntFlag(cli.IntFlag{Name: "test, t", Value: -1}),
        altsrc.NewStringFlag(cli.StringFlag{Name: "flag", Value: "default"}),

        /*  
            // NG #2
            altsrc.NewIntFlag(cli.IntFlag{Name: "test", Value: -1}),
            altsrc.NewStringFlag(cli.StringFlag{Name: "flag, f", Value: "default"}),

            // NG #3
            altsrc.NewIntFlag(cli.IntFlag{Name: "test, t", Value: -1}),
            altsrc.NewStringFlag(cli.StringFlag{Name: "flag, f", Value: "default"}),
        */

        cli.StringFlag{Name: "load, l"},
    }   

    app.Action = func(c *cli.Context) error {
        fmt.Println("yaml ist rad")
        fmt.Printf("load: %s\n", c.String("load"))
        fmt.Printf("test: %d\n", c.Int("test"))
        fmt.Printf("flag: %s\n", c.String("flag"))
        return nil 
    }   

    app.Before = altsrc.InitInputSourceWithContext(flags, altsrc.NewYamlSourceFromFlagFunc("load"))
    app.Flags = flags

    app.Run(os.Args)
}

Test file contents:

iMac:buggy chris$ cat buggy.txt
test: 123
flag: excellent!
iMac:buggy chris$

Output:

iMac:buggy chris$ go run buggy.go --load buggy.txt
yaml ist rad
load: buggy.txt
test: -1
flag: excellent!
iMac:buggy chris$

Have not had a chance to debug this as of yet, but documenting it for now in case others encounter this problem.

[jszwedko]

Thanks for the detailed bug report @wcwynn ! It does look like there are a few places where altsrc assumes that the defined flags only have one "name" specified.

[rmoriz]

FYI: this also affects TOML.

[pysqz]

@wcwynn PR #791 can fix this bug. @jszwedko @meatballhat please review this commits

[mdbraber]

Also mentioned this in #791, this doesn't seem to fix problems with GlobalStringSliceFlag

[pysqz]

please review #792. it fix problems with *SliceFlag. @mdbraber

[coilysiren]

Hiya! There's a known issue with the current implementation of the CLI, where altsrc is generally clunky and poorly documented. My current idea is that I'm going to move all of the altsrc functionality into the main package in some way, and that's how all of the "altsrc is weird and different???" issues people are having will get resolved. I'm tracking that work here => #833