Allow passing rawargs to commands

Author: Nathan Potter

command.go

@@ -19,6 +19,9 @@ type CommandSpec struct {
 	// Desc is the description of the command.
 	// The first line is used as an abbreviated description.
 	Desc string
+	// RawArgs indicates that flags should not be parsed, and they should be deferred
+	// to the command.
+	RawArgs bool
 
 	// Hidden indicates that this command should not show up in it's parent's
 	// subcommand help.

run.go

@@ -1,15 +1,15 @@
 package cli
 
 import (
-    "flag"
-    "os"
+	"flag"
+	"os"
 )
 
 func appendParent(parent string, add string) string {
-    if parent == "" {
-        return add + " "
-    }
-    return parent + add + " "
+	if parent == "" {
+		return add + " "
+	}
+	return parent + add + " "
 }
 
 // Run sets up flags, helps, and executes the command with the provided
@@ -20,38 +20,43 @@ func appendParent(parent string, add string) string {
 //
 // Use RunRoot if this package is managing the entire CLI.
 func Run(cmd Command, args []string, parent string) {
-    fl := flag.NewFlagSet(parent+""+cmd.Spec().Name, flag.ExitOnError)
-
-    if fc, ok := cmd.(FlaggedCommand); ok {
-        fc.RegisterFlags(fl)
-    }
-
-    fl.Usage = func() {
-        renderHelp(cmd, fl, os.Stderr)
-    }
-    _ = fl.Parse(args)
-
-    subcommandArg := fl.Arg(0)
-
-    // Route to subcommand.
-    if pc, ok := cmd.(ParentCommand); ok && subcommandArg != "" {
-        for _, subcommand := range pc.Subcommands() {
-            if subcommand.Spec().Name != subcommandArg {
-                continue
-            }
-
-            Run(
-                subcommand, fl.Args()[1:],
-                appendParent(parent, cmd.Spec().Name),
-            )
-            return
-        }
-    }
-
-    cmd.Run(fl)
+	fl := flag.NewFlagSet(parent+""+cmd.Spec().Name, flag.ExitOnError)
+
+	if fc, ok := cmd.(FlaggedCommand); ok {
+		fc.RegisterFlags(fl)
+	}
+
+	fl.Usage = func() {
+		renderHelp(cmd, fl, os.Stderr)
+	}
+
+	if cmd.Spec().RawArgs {
+		// Use `--` to return immediately when parsing the flags.
+		args = append([]string{"--"}, args...)
+	}
+	_ = fl.Parse(args)
+
+	subcommandArg := fl.Arg(0)
+
+	// Route to subcommand.
+	if pc, ok := cmd.(ParentCommand); ok && subcommandArg != "" {
+		for _, subcommand := range pc.Subcommands() {
+			if subcommand.Spec().Name != subcommandArg {
+				continue
+			}
+
+			Run(
+				subcommand, fl.Args()[1:],
+				appendParent(parent, cmd.Spec().Name),
+			)
+			return
+		}
+	}
+
+	cmd.Run(fl)
 }
 
 // RunRoot calls Run with the process's arguments.
 func RunRoot(cmd Command) {
-    Run(cmd, os.Args[1:], "")
+	Run(cmd, os.Args[1:], "")
 }