Add helpers.NormalizeHugoFlagsFunc() to handle flag name changes

It currently handles --baseUrl to --baseURL, and --uglyUrls to --uglyURLs.

Special thanks to Eric Paris (@eparis) for writing the
"normalized name" support in Cobra, and for showing us
how it is used in Kubernetes.

See Issue gohugoio#959

commands/hugo.go

@@ -63,6 +63,7 @@ var Source, CacheDir, Destination, Theme, BaseURL, CfgFile, LogFile, Editor stri
 
 //Execute adds all child commands to the root command HugoCmd and sets flags appropriately.
 func Execute() {
+	HugoCmd.SetGlobalNormalizationFunc(helpers.NormalizeHugoFlagsFunc)
 	AddCommands()
 	utils.StopOnErr(HugoCmd.Execute())
 }
@@ -94,8 +95,8 @@ func init() {
 	HugoCmd.PersistentFlags().StringVarP(&Destination, "destination", "d", "", "filesystem path to write files to")
 	HugoCmd.PersistentFlags().StringVarP(&Theme, "theme", "t", "", "theme to use (located in /themes/THEMENAME/)")
 	HugoCmd.PersistentFlags().BoolVarP(&Verbose, "verbose", "v", false, "verbose output")
-	HugoCmd.PersistentFlags().BoolVar(&UglyURLs, "uglyUrls", false, "if true, use /filename.html instead of /filename/")
-	HugoCmd.PersistentFlags().StringVarP(&BaseURL, "baseUrl", "b", "", "hostname (and path) to the root eg. http://spf13.com/")
+	HugoCmd.PersistentFlags().BoolVar(&UglyURLs, "uglyURLs", false, "if true, use /filename.html instead of /filename/")
+	HugoCmd.PersistentFlags().StringVarP(&BaseURL, "baseURL", "b", "", "hostname (and path) to the root, e.g. http://spf13.com/")
 	HugoCmd.PersistentFlags().StringVar(&CfgFile, "config", "", "config file (default is path/config.yaml|json|toml)")
 	HugoCmd.PersistentFlags().StringVar(&Editor, "editor", "", "edit new content with this editor, if provided")
 	HugoCmd.PersistentFlags().BoolVar(&Logging, "log", false, "Enable Logging")
@@ -189,7 +190,7 @@ func InitializeConfig() {
 		viper.Set("BuildFuture", Future)
 	}
 
-	if hugoCmdV.PersistentFlags().Lookup("uglyUrls").Changed {
+	if hugoCmdV.PersistentFlags().Lookup("uglyURLs").Changed {
 		viper.Set("UglyURLs", UglyURLs)
 	}
 

helpers/general.go

@@ -31,6 +31,7 @@ import (
 	"github.com/spf13/cast"
 	bp "github.com/spf13/hugo/bufferpool"
 	jww "github.com/spf13/jwalterweatherman"
+	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
 )
 
@@ -428,3 +429,17 @@ func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
 		return nil, errors.New("There is no such an operation")
 	}
 }
+
+// NormalizeHugoFlagsFunc facilitates transitions of Hugo command-line flags,
+// e.g. --baseUrl to --baseURL, --uglyUrls to --uglyURLs
+func NormalizeHugoFlagsFunc(f *pflag.FlagSet, name string) pflag.NormalizedName {
+	switch name {
+	case "baseUrl":
+		name = "baseURL"
+		break
+	case "uglyUrls":
+		name = "uglyURLs"
+		break
+	}
+	return pflag.NormalizedName(name)
+}