Do not create robots.txt by default

Meny people, including me, have a custom robots.txt in static.

Also remove that option from the command line; it doesn't feel
important enough.

Fixes ##2049

commands/hugo.go

@@ -126,7 +126,7 @@ var (
 	buildWatch            bool
 	canonifyURLs          bool
 	cleanDestination      bool
-	disableRobotsTXT      bool
+	enableRobotsTXT       bool
 	disableRSS            bool
 	disableSitemap        bool
 	draft                 bool
@@ -216,7 +216,6 @@ func initHugoBuildCommonFlags(cmd *cobra.Command) {
 	cmd.Flags().BoolVarP(&future, "buildFuture", "F", false, "include content with publishdate in the future")
 	cmd.Flags().BoolVar(&disableRSS, "disableRSS", false, "Do not build RSS files")
 	cmd.Flags().BoolVar(&disableSitemap, "disableSitemap", false, "Do not build Sitemap file")
-	cmd.Flags().BoolVar(&disableRobotsTXT, "disableRobotsTXT", false, "Do not build Robots TXT file")
 	cmd.Flags().StringVarP(&source, "source", "s", "", "filesystem path to read files relative from")
 	cmd.Flags().StringVarP(&contentDir, "contentDir", "c", "", "filesystem path to content directory")
 	cmd.Flags().StringVarP(&layoutDir, "layoutDir", "l", "", "filesystem path to layout directory")
@@ -364,8 +363,8 @@ func InitializeConfig(subCmdVs ...*cobra.Command) error {
 		if flagChanged(cmdV.Flags(), "disableSitemap") {
 			viper.Set("DisableSitemap", disableSitemap)
 		}
-		if flagChanged(cmdV.Flags(), "disableRobotsTXT") {
-			viper.Set("DisableRobotsTXT", disableRobotsTXT)
+		if flagChanged(cmdV.Flags(), "enableRobotsTXT") {
+			viper.Set("EnableRobotsTXT", enableRobotsTXT)
 		}
 		if flagChanged(cmdV.Flags(), "pluralizeListTitles") {
 			viper.Set("PluralizeListTitles", pluralizeListTitles)

docs/content/extras/robots-txt.md

@@ -13,13 +13,12 @@ weight: 120
 Hugo can generated a customized [robots.txt](http://www.robotstxt.org/) in the
 [same way as any other templates]({{< ref "templates/go-templates.md" >}}).
 
-By default, it generates a robots.txt, which allows everything, with the following content:
+To enable it, just set `enableRobotsTXT` option to `true` in the [configuration file]({{< ref "overview/configuration.md" >}}). By default, it generates a robots.txt, which allows everything, with the following content:
 
 ```http
 User-agent: *
 ```
 
-To disable it, just set `disableRobotsTXT` option to `false` in the [command line]({{< ref "commands/hugo.md" >}}) or [configuration file]({{< ref "overview/configuration.md" >}}).
 
 Hugo will use the template `robots.txt` according to the following list in descending precedence:
 

docs/content/overview/configuration.md

@@ -95,8 +95,8 @@ Following is a list of Hugo-defined variables that you can configure and their c
     disableRSS:                 false
     # Do not build Sitemap file
     disableSitemap:             false
-    # Do not build robots.txt file
-    disableRobotsTXT:           false
+    # Build robots.txt file
+    enableRobotsTXT:           false
     # edit new content with this editor, if provided
     editor:                     ""
     # Enable Emoji emoticons support for page content.

hugolib/robotstxt_test.go

@@ -36,6 +36,7 @@ func TestRobotsTXTOutput(t *testing.T) {
 	hugofs.InitMemFs()
 
 	viper.Set("baseurl", "http://auth/bub/")
+	viper.Set("enableRobotsTXT", true)
 
 	s := &Site{
 		Source: &source.InMemorySource{ByteSource: WEIGHTED_SOURCES},

hugolib/site.go

@@ -1864,7 +1864,7 @@ func (s *Site) RenderSitemap() error {
 }
 
 func (s *Site) RenderRobotsTXT() error {
-	if viper.GetBool("DisableRobotsTXT") {
+	if !viper.GetBool("EnableRobotsTXT") {
 		return nil
 	}