mcfg: don't allow for empty sub-command, as that makes printing help weird

mcfg/cli.go

@@ -59,9 +59,7 @@ type subCmd struct {
 // support for sub-sub-commands, and more. The callback may be nil.
 //
 // If any sub-commands have been defined on a Context which is passed into
-// Parse, it is assumed that a sub-command is required on the command-line. The
+// Parse, it is assumed that a sub-command is required on the command-line.
-// exception is if a sub-command with a name of "" has been defined; if so, it
-// will be used as the intended sub-command if none is specified.
 //
 // Sub-commands must be specified before any other options on the command-line.
 func WithCLISubCommand(ctx context.Context, name, descr string, callback func(context.Context) context.Context) (context.Context, *bool) {
@@ -156,9 +154,7 @@ func (cli *SourceCLI) parse(
 		if subCmd.callback != nil {
 			ctx = subCmd.callback(ctx)
 		}
-		if subCmd.name != "" {
+		subCmdPrefix = append(subCmdPrefix, subCmd.name)
-			subCmdPrefix = append(subCmdPrefix, subCmd.name)
-		}
 		*subCmd.flag = true
 		return cli.parse(ctx, subCmdPrefix, args)
 	}
@@ -238,20 +234,16 @@ func (cli *SourceCLI) parse(
 }
 
 func (cli *SourceCLI) getSubCmd(subCmdM map[string]subCmd, args []string) (subCmd, []string, bool) {
-	// if a proper sub-command is given then great, return that
+	if len(args) == 0 {
-	if len(args) > 0 {
+		return subCmd{}, args, false
-		if subCmd, ok := subCmdM[args[0]]; ok {
-			return subCmd, args[1:], true
-		}
 	}
 
-	// if the empty subCmd is set in the map it means an absent sub-command is
+	s, ok := subCmdM[args[0]]
-	// allowed, check if that's the case
+	if !ok {
-	if subCmd, ok := subCmdM[""]; ok {
+		return subCmd{}, args, false
-		return subCmd, args, true
 	}
 
-	return subCmd{}, args, false
+	return s, args[1:], true
 }
 
 func (cli *SourceCLI) cliParams(params []Param) (map[string]Param, error) {
@@ -307,9 +299,6 @@ func (cli *SourceCLI) printHelp(
 
 	subCmdA := make([]subCmdEntry, 0, len(subCmdM))
 	for name, subCmd := range subCmdM {
-		if name == "" {
-			name = "<None>"
-		}
 		subCmdA = append(subCmdA, subCmdEntry{name: name, subCmd: subCmd})
 	}
 
@@ -322,11 +311,7 @@ func (cli *SourceCLI) printHelp(
 		fmt.Fprintf(w, " %s", strings.Join(subCmdPrefix, " "))
 	}
 	if len(subCmdA) > 0 {
-		if _, ok := subCmdM[""]; ok {
+		fmt.Fprint(w, " <sub-command>")
-			fmt.Fprint(w, " [sub-command]")
-		} else {
-			fmt.Fprint(w, " <sub-command>")
-		}
 	}
 	if len(pA) > 0 {
 		fmt.Fprint(w, " [options]")

mcfg/cli_test.go

@@ -106,32 +106,6 @@ Options:
 	--foo \(Default: 5\)
 		Test int param.
 
-$`)
-
-	ctx, _ = WithCLISubCommand(ctx, "", "No sub-command", nil)
-	assertHelp(ctx, []string{"foo", "bar"}, `^Usage: \S+ foo bar \[sub-command\] \[options\]
-
-Sub-commands:
-
-	<None>	No sub-command
-	first	First sub-command
-	second	Second sub-command
-
-Options:
-
-	--baz2 \(Required\)
-
-	--baz3 \(Required\)
-
-	--bar \(Flag\)
-		Test bool param.
-
-	--baz \(Default: "baz"\)
-		Test string param.
-
-	--foo \(Default: 5\)
-		Test int param.
-
 $`)
 }
 
@@ -255,15 +229,15 @@ func ExampleWithCLITail() {
 
 func TestWithCLISubCommand(t *T) {
 	var (
-		ctx         context.Context
+		ctx   context.Context
-		foo         *int
+		foo   *int
-		bar         *int
+		bar   *int
-		baz         *int
+		baz   *int
-		aFlag       *bool
+		aFlag *bool
-		defaultFlag *bool
+		bFlag *bool
 	)
 	reset := func() {
-		foo, bar, baz, aFlag, defaultFlag = nil, nil, nil, nil, nil
+		foo, bar, baz, aFlag, bFlag = nil, nil, nil, nil, nil
 		ctx = context.Background()
 		ctx, foo = WithInt(ctx, "foo", 0, "Description of foo.")
 		ctx, aFlag = WithCLISubCommand(ctx, "a", "Description of a.",
@@ -271,7 +245,7 @@ func TestWithCLISubCommand(t *T) {
 				ctx, bar = WithInt(ctx, "bar", 0, "Description of bar.")
 				return ctx
 			})
-		ctx, defaultFlag = WithCLISubCommand(ctx, "", "Description of default.",
+		ctx, bFlag = WithCLISubCommand(ctx, "b", "Description of b.",
 			func(ctx context.Context) context.Context {
 				ctx, baz = WithInt(ctx, "baz", 0, "Description of baz.")
 				return ctx
@@ -288,12 +262,12 @@ func TestWithCLISubCommand(t *T) {
 		massert.Equal(2, *bar),
 		massert.Nil(baz),
 		massert.Equal(true, *aFlag),
-		massert.Equal(false, *defaultFlag),
+		massert.Equal(false, *bFlag),
 	)
 
 	reset()
 	_, err = Populate(ctx, &SourceCLI{
-		Args: []string{"--foo=1", "--baz=3"},
+		Args: []string{"b", "--foo=1", "--baz=3"},
 	})
 	massert.Require(t,
 		massert.Comment(massert.Nil(err), "%v", err),
@@ -301,7 +275,7 @@ func TestWithCLISubCommand(t *T) {
 		massert.Nil(bar),
 		massert.Equal(3, *baz),
 		massert.Equal(false, *aFlag),
-		massert.Equal(true, *defaultFlag),
+		massert.Equal(true, *bFlag),
 	)
 }
 
@@ -317,7 +291,7 @@ func ExampleWithCLISubCommand() {
 		})
 
 	var baz *int
-	ctx, defaultFlag := WithCLISubCommand(ctx, "", "Description of default.",
+	ctx, bFlag := WithCLISubCommand(ctx, "b", "Description of b.",
 		func(ctx context.Context) context.Context {
 			ctx, baz = WithInt(ctx, "baz", 0, "Description of baz.")
 			return ctx
@@ -327,16 +301,16 @@ func ExampleWithCLISubCommand() {
 	if _, err := Populate(ctx, &SourceCLI{Args: args}); err != nil {
 		panic(err)
 	}
-	fmt.Printf("foo:%d bar:%d aFlag:%v defaultFlag:%v\n", *foo, *bar, *aFlag, *defaultFlag)
+	fmt.Printf("foo:%d bar:%d aFlag:%v bFlag:%v\n", *foo, *bar, *aFlag, *bFlag)
 
 	// reset output for another Populate
 	*aFlag = false
-	args = []string{"--foo=1", "--baz=3"}
+	args = []string{"b", "--foo=1", "--baz=3"}
 	if _, err := Populate(ctx, &SourceCLI{Args: args}); err != nil {
 		panic(err)
 	}
-	fmt.Printf("foo:%d baz:%d aFlag:%v defaultFlag:%v\n", *foo, *baz, *aFlag, *defaultFlag)
+	fmt.Printf("foo:%d baz:%d aFlag:%v bFlag:%v\n", *foo, *baz, *aFlag, *bFlag)
 
-	// Output: foo:1 bar:2 aFlag:true defaultFlag:false
+	// Output: foo:1 bar:2 aFlag:true bFlag:false
-	// foo:1 baz:3 aFlag:false defaultFlag:true
+	// foo:1 baz:3 aFlag:false bFlag:true
 }