add the [OPTIONS] string automatically if there are flags defined

Signed-off-by: SvenDowideit <SvenDowideit@home.org.au>

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)

mflag/flag.go

@@ -472,6 +472,23 @@ var Usage = func() {
 	PrintDefaults()
 }
 
+// FlagCount returns the number of flags that have been defined.
+func (f *FlagSet) FlagCount() int { return len(f.formal) }
+
+// FlagCountUndeprecated returns the number of undeprecated flags that have been defined.
+func (f *FlagSet) FlagCountUndeprecated() int {
+	count := 0
+	for _, flag := range sortFlags(f.formal) {
+		for _, name := range flag.Names {
+			if name[0] != '#' {
+				count++
+				break
+			}
+		}
+	}
+	return count
+}
+
 // NFlag returns the number of flags that have been set.
 func (f *FlagSet) NFlag() int { return len(f.actual) }
 

mflag/flag_test.go

@@ -428,3 +428,32 @@ func TestHelp(t *testing.T) {
 		t.Fatal("help was called; should not have been for defined help flag")
 	}
 }
+
+// Test the flag count functions.
+func TestFlagCounts(t *testing.T) {
+	fs := NewFlagSet("help test", ContinueOnError)
+	var flag bool
+	fs.BoolVar(&flag, []string{"flag1"}, false, "regular flag")
+	fs.BoolVar(&flag, []string{"#deprecated1"}, false, "regular flag")
+	fs.BoolVar(&flag, []string{"f", "flag2"}, false, "regular flag")
+	fs.BoolVar(&flag, []string{"#d", "#deprecated2"}, false, "regular flag")
+	fs.BoolVar(&flag, []string{"flag3"}, false, "regular flag")
+	fs.BoolVar(&flag, []string{"g", "#flag4", "-flag4"}, false, "regular flag")
+
+	if fs.FlagCount() != 10 {
+		t.Fatal("FlagCount wrong. ", fs.FlagCount())
+	}
+	if fs.FlagCountUndeprecated() != 4 {
+		t.Fatal("FlagCountUndeprecated wrong. ", fs.FlagCountUndeprecated())
+	}
+	if fs.NFlag() != 0 {
+		t.Fatal("NFlag wrong. ", fs.NFlag())
+	}
+	err := fs.Parse([]string{"-fd", "-g", "-flag4"})
+	if err != nil {
+		t.Fatal("expected no error for defined -help; got ", err)
+	}
+	if fs.NFlag() != 4 {
+		t.Fatal("NFlag wrong. ", fs.NFlag())
+	}
+}