BoolFlag.Count increment once per alias

[matthewhughes934]

My urfave/cli version is

v2.25.3

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
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Dependency Management

• My project is using go modules.

Describe the bug

The value of .Count for a BoolFlag is impacted by the number of aliases defined for that flag.

To reproduce

Reproducible program:

package main

import (
	"fmt"
	"os"

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

func main() {
	verbosity := 0
	
	app := &cli.App{
		Flags: []cli.Flag{
			&cli.BoolFlag{
				Name: "verbose",
				Aliases: []string{"v"},
				Count: &verbosity,
			},
		},
		Action: func(c *cli.Context) error {
			fmt.Printf("Running with verbosity: %d\n", verbosity)
			return nil
		},
	}

	app.Run(os.Args)
}

Observed behavior

$ go run main.go -v
Running with verbosity: 2

Expected behavior

I would expect the count to be incremented only once, i.e.:

$ go run main.go -v
Running with verbosity: 1

Additional context

Beyond the initial value, things are incremented as expected:

$ go run main.go -v -v
Running with verbosity: 3

Want to fix this yourself?

I'd be happy to, though I don't think I have enough context to implement a suitable solution. The trace is:

• When we .Apply a BoolFlag we copy the count pointer for each alias

  cli/flag_bool.go

  Line 138 in dc77f3c

  value := newBoolValue(f.Value, dest, count)

• And when we .Set the flag we increment this count

  cli/flag_bool.go

  Line 38 in dc77f3c

  *b.count = *b.count + 1

So when we run a command:

• We parse the flags

  cli/command.go

  Line 158 in acbbbf2

  set, err := c.parseFlags(&a, cCtx)

• Which requires normalizing

  cli/command.go

  Line 384 in acbbbf2

  if err := normalizeFlags(c.Flags, set); err != nil {

• When normalizing we copy for each alias we didn't see

  cli/flag.go

  Line 229 in acbbbf2

  copyFlag(name, ff, set)

• Which in turn sets the value

  cli/flag.go

  Line 199 in acbbbf2

  _ = set.Set(name, ff.Value.String())

Consequently the flag is .Set once per alias, so the count is incremented once per alias.

Maybe flag types could implement the copying logic themselves?

Run go version and paste its output here

$ go version
go version go1.20.4 linux/amd64

Run go env and paste its output here

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/user/.cache/go-build"
GOENV="/home/user/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/user/.local/share/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/user/.local/share/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.20.4"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/user/src/cli/go.mod"
GOWORK=""
CGO_CFLAGS="-O2 -g"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-O2 -g"
CGO_FFLAGS="-O2 -g"
CGO_LDFLAGS="-O2 -g"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3085526498=/tmp/go-build -gno-record-gcc-switches"

[dearchap]

@matthewhughes934 Try this "fix"