kubeletctl panics when no arguments are provided to some commands #5
Description
kubeletctl commands that require arguments cause a panicif no arguments are provided. I confirmed this behaviour with this release.
$ ./kubeletctl --http --server REDACTED --port 10255 debug
panic: runtime error: index out of range [0] with length 0
goroutine 1 [running]:
kubeletctl/cmd/proxy/debug.glob..func1(0x15708a0, 0xc00034e320, 0x0, 0x5)
/home/ubuntu/test/kubeletctl/cmd/proxy/debug/debug.go:89 +0x1e1
github.com/spf13/cobra.(*Command).execute(0x15708a0, 0xc00034e2d0, 0x5, 0x5, 0x15708a0, 0xc00034e2d0)
/home/ubuntu/test/kubeletctl/vendor/github.com/spf13/cobra/command.go:842 +0x29d
github.com/spf13/cobra.(*Command).ExecuteC(0x156dea0, 0x443cba, 0x151f1a0, 0xc000000180)
/home/ubuntu/test/kubeletctl/vendor/github.com/spf13/cobra/command.go:943 +0x317
github.com/spf13/cobra.(*Command).Execute(...)
/home/ubuntu/test/kubeletctl/vendor/github.com/spf13/cobra/command.go:883
kubeletctl/cmd.Execute()
/home/ubuntu/test/kubeletctl/cmd/root.go:66 +0x31
main.main()
/home/ubuntu/test/kubeletctl/main.go:20 +0x20Panic comes from the following snippet:
var inputArgs string
if args == nil {
fmt.Println("[*] No debug profile was specified")
os.Exit(1)
} else {
inputArgs = args[0]
}The error comes from checking if the arguments slice is nil instead of checking the number of arguments (length of a nil slice is 0 too, see the playground). If no arguments are provided, cobra passes an empty slice as argument, not nil.
I confirmed this behaviour in the debug and exec commands, but it might be present in more of them.
I built this small repro so you can check cobra's behaviour when no arguments are provided:
package main
import (
"fmt"
"github.com/spf13/cobra"
)
func main() {
cmdPrint := &cobra.Command{
Use: "print [str]",
Run: func(_ *cobra.Command, args []string) {
fmt.Printf("args: %#+v\n", args)
},
}
rootCmd := &cobra.Command{Use: "app"}
rootCmd.AddCommand(cmdPrint)
rootCmd.Execute()
}:/tmp/example$ go run main.go print
args: []string{}
:/tmp/example$ go run main.go print foo
args: []string{"foo"}Regards,
Miguel