Merge pull request #60 from dohzya/remove-command

Add Command's RemoveCommand method

README.md

@@ -143,6 +143,15 @@ A flag can also be assigned locally which will only apply to that specific comma
 
 	HugoCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from")
 
+### Remove a command from its parent
+
+Removing a command is not a common action is simple program but it allows 3rd parties to customize an existing command tree.
+
+In this exemple, we remove the existing `VersionCmd` command of an existing root command, and we replace it by our own version.
+
+	mainlib.RootCmd.RemoveCommand(mainlib.VersionCmd)
+	mainlib.RootCmd.AddCommand(versionCmd)
+
 ### Once all commands and flags are defined, Execute the commands
 
 Execute should be run on the root for clarity, though it can be called on any command.

cobra_test.go

@@ -17,6 +17,7 @@ var flags1, flags2a, flags2b, flags3 string
 var flagi1, flagi2, flagi3, flagir int
 var globalFlag1 bool
 var flagEcho, rootcalled bool
+var versionUsed int
 
 const strtwoParentHelp = "help message for parent flag strtwo"
 const strtwoChildHelp = "help message for child flag strtwo"
@@ -70,6 +71,24 @@ var cmdRootWithRun = &Command{
 	},
 }
 
+var cmdVersion1 = &Command{
+	Use:   "version",
+	Short: "Print the version number",
+	Long:  `First version of the version command`,
+	Run: func(cmd *Command, args []string) {
+		versionUsed = 1
+	},
+}
+
+var cmdVersion2 = &Command{
+	Use:   "version",
+	Short: "Print the version number",
+	Long:  `Second version of the version command`,
+	Run: func(cmd *Command, args []string) {
+		versionUsed = 2
+	},
+}
+
 func flagInit() {
 	cmdEcho.ResetFlags()
 	cmdPrint.ResetFlags()
@@ -88,6 +107,8 @@ func flagInit() {
 	cmdEcho.Flags().BoolVarP(&flagb1, "boolone", "b", true, "help message for flag boolone")
 	cmdTimes.Flags().BoolVarP(&flagb2, "booltwo", "c", false, "help message for flag booltwo")
 	cmdPrint.Flags().BoolVarP(&flagb3, "boolthree", "b", true, "help message for flag boolthree")
+	cmdVersion1.ResetFlags()
+	cmdVersion2.ResetFlags()
 }
 
 func commandInit() {
@@ -697,3 +718,34 @@ func TestFlagsBeforeCommand(t *testing.T) {
 	}
 
 }
+
+func TestRemoveCommand(t *testing.T) {
+	versionUsed = 0
+	c := initializeWithRootCmd()
+	c.AddCommand(cmdVersion1)
+	c.RemoveCommand(cmdVersion1)
+	x := fullTester(c, "version")
+	if x.Error == nil {
+		t.Errorf("Removed command should not have been called\n")
+		return
+	}
+}
+
+func TestReplaceCommandWithRemove(t *testing.T) {
+	versionUsed = 0
+	c := initializeWithRootCmd()
+	c.AddCommand(cmdVersion1)
+	c.RemoveCommand(cmdVersion1)
+	c.AddCommand(cmdVersion2)
+	x := fullTester(c, "version")
+	if x.Error != nil {
+		t.Errorf("Valid Input shouldn't have errors, got:\n %q", x.Error)
+		return
+	}
+	if versionUsed == 1 {
+		t.Errorf("Removed command shouldn't be called\n")
+	}
+	if versionUsed != 2 {
+		t.Errorf("Replacing command should have been called but didn't\n")
+	}
+}