node to page: Fix the Page copy()

By embeding the init sync.Once var in a pointer so we can reset it when we copy the page.

Updates #2297

hugolib/hugo_sites.go

@@ -304,6 +304,7 @@ func (h *HugoSites) createMissingPages() error {
 // Move the new* methods after cleanup in site.go
 func (s *Site) newNodePage(typ string) *Page {
 	return &Page{
+		pageInit: &pageInit{},
 		Kind:     typ,
 		Data:     make(map[string]interface{}),
 		Site:     &s.Info,

hugolib/page.go

@@ -70,6 +70,7 @@ const (
 )
 
 type Page struct {
+	*pageInit
 
 	// Kind is the discriminator that identifies the different page types
 	// in the different page collections. This can, as an example, be used
@@ -147,16 +148,12 @@ type Page struct {
 	// the content stripped for HTML
 	plain      string // TODO should be []byte
 	plainWords []string
-	plainInit      sync.Once
-	plainWordsInit sync.Once
 
 	// rendering configuration
 	renderingConfig *helpers.Blackfriday
-	renderingConfigInit sync.Once
 
 	// menus
 	pageMenus PageMenus
-	pageMenusInit sync.Once
 
 	Source
 
@@ -197,15 +194,25 @@ type Page struct {
 	URLPath
 
 	paginator *Pager
-	paginatorInit sync.Once
 
 	scratch *Scratch
 
 	language *helpers.Language
-	languageInit sync.Once
 	lang     string
 }
 
+// pageInit lazy initializes different parts of the page. It is extracted
+// into its own type so we can easily create a copy of a given page.
+type pageInit struct {
+	languageInit        sync.Once
+	pageMenusInit       sync.Once
+	pageMetaInit        sync.Once
+	paginatorInit       sync.Once
+	plainInit           sync.Once
+	plainWordsInit      sync.Once
+	renderingConfigInit sync.Once
+}
+
 // IsNode returns whether this is an item of one of the list types in Hugo,
 // i.e. not a regular content page.
 func (p *Page) IsNode() bool {
@@ -231,7 +238,6 @@ type PageMeta struct {
 	wordCount      int
 	fuzzyWordCount int
 	readingTime    int
-	pageMetaInit   sync.Once
 	Weight         int
 }
 
@@ -532,6 +538,7 @@ func (p *Page) getRenderingConfig() *helpers.Blackfriday {
 
 func newPage(filename string) *Page {
 	page := Page{
+		pageInit:    &pageInit{},
 		Kind:        kindFromFilename(filename),
 		contentType: "",
 		Source:      Source{File: *source.NewFile(filename)},
@@ -1538,20 +1545,12 @@ func (p *Page) updatePageDates() {
 	}
 }
 
-// Page constains some sync.Once which have a mutex, so we cannot just
+// copy creates a copy of this page with the lazy sync.Once vars reset
-// copy the Page by value. So for the situations where we need a copy,
+// so they will be evaluated again, for word count calculations etc.
-// the paginators etc., we do it manually here.
-// TODO(bep) np do better
 func (p *Page) copy() *Page {
-	c := &Page{Kind: p.Kind, Site: p.Site}
+	c := *p
-	c.Title = p.Title
+	c.pageInit = &pageInit{}
-	c.Data = p.Data
+	return &c
-	c.Date = p.Date
-	c.Lastmod = p.Lastmod
-	c.language = p.language
-	c.lang = p.lang
-	c.URLPath = p.URLPath
-	return c
 }
 
 // TODO(bep) np these are pulled over from Node. Needs regrouping / embed

hugolib/pageSort_test.go

@@ -147,7 +147,7 @@ func createSortTestPages(num int) Pages {
 
 	for i := 0; i < num; i++ {
 		pages[i] = &Page{
-
+			pageInit: &pageInit{},
 			URLPath: URLPath{
 				Section: "z",
 				URL:     fmt.Sprintf("http://base/x/y/p%d.html", i),

hugolib/page_permalink_test.go

@@ -66,6 +66,7 @@ func TestPermalink(t *testing.T) {
 		info := newSiteInfo(siteBuilderCfg{baseURL: string(test.base), language: helpers.NewDefaultLanguage()})
 
 		p := &Page{
+			pageInit: &pageInit{},
 			Kind:     KindPage,
 			URLPath: URLPath{
 				Section: "z",

hugolib/page_test.go

@@ -1269,7 +1269,7 @@ func TestIndexPageSimpleMethods(t *testing.T) {
 		{func(n *Page) bool { return n.Now().Unix() == time.Now().Unix() }},
 	} {
 
-		n := &Page{Kind: KindHome}
+		n := &Page{pageInit: &pageInit{}, Kind: KindHome}
 		n.RSSLink = "rssLink"
 
 		if !this.assertFunc(n) {

hugolib/pagination_test.go

@@ -457,6 +457,7 @@ func createTestPages(num int) Pages {
 	info := newSiteInfo(siteBuilderCfg{baseURL: "http://base/", language: helpers.NewDefaultLanguage()})
 	for i := 0; i < num; i++ {
 		pages[i] = &Page{
+			pageInit: &pageInit{},
 			URLPath: URLPath{
 				Section: "z",
 				URL:     fmt.Sprintf("http://base/x/y/p%d.html", i),