Fix menu URL when multiple permalinkable output formats

In Hugo `0.55` we introduced the `permalinkable` config attribute on Output Format, default enabled for `AMP` and `HTML`.

This meant that a Page could have different `RelPermalink` and `Permalink` depending on the rendering format.

The menu `URL` did not reflect that fact.

Fixes #5849

2 files changed, 34 insertions, 21 deletions

diff --git a/navigation/menu.go b/navigation/menu.go
index 66721ea8a..47d40a3c7 100644
--- a/navigation/menu.go
+++ b/navigation/menu.go
@@ -14,6 +14,8 @@
 package navigation
 
 import (
+	"github.com/gohugoio/hugo/common/types"
+
 	"html/template"
 	"sort"
 	"strings"
@@ -24,17 +26,29 @@ import (
 // MenuEntry represents a menu item defined in either Page front matter
 // or in the site config.
 type MenuEntry struct {
-	URL        string
-	Page       Page
-	Name       string
-	Menu       string
-	Identifier string
-	title      string
-	Pre        template.HTML
-	Post       template.HTML
-	Weight     int
-	Parent     string
-	Children   Menu
+	ConfiguredURL string // The URL value from front matter / config.
+	Page          Page
+	Name          string
+	Menu          string
+	Identifier    string
+	title         string
+	Pre           template.HTML
+	Post          template.HTML
+	Weight        int
+	Parent        string
+	Children      Menu
+}
+
+func (m *MenuEntry) URL() string {
+	if m.ConfiguredURL != "" {
+		return m.ConfiguredURL
+	}
+
+	if !types.IsNil(m.Page) {
+		return m.Page.RelPermalink()
+	}
+
+	return ""
 }
 
 // A narrow version of page.Page.
@@ -72,8 +86,8 @@ func (m *MenuEntry) KeyName() string {
 func (m *MenuEntry) hopefullyUniqueID() string {
 	if m.Identifier != "" {
 		return m.Identifier
-	} else if m.URL != "" {
-		return m.URL
+	} else if m.URL() != "" {
+		return m.URL()
 	} else {
 		return m.Name
 	}
@@ -87,7 +101,8 @@ func (m *MenuEntry) IsEqual(inme *MenuEntry) bool {
 // IsSameResource returns whether the two menu entries points to the same
 // resource (URL).
 func (m *MenuEntry) IsSameResource(inme *MenuEntry) bool {
-	return m.URL != "" && inme.URL != "" && m.URL == inme.URL
+	murl, inmeurl := m.URL(), inme.URL()
+	return murl != "" && inmeurl != "" && murl == inmeurl
 }
 
 func (m *MenuEntry) MarshallMap(ime map[string]interface{}) {
@@ -95,7 +110,7 @@ func (m *MenuEntry) MarshallMap(ime map[string]interface{}) {
 		loki := strings.ToLower(k)
 		switch loki {
 		case "url":
-			m.URL = cast.ToString(v)
+			m.ConfiguredURL = cast.ToString(v)
 		case "weight":
 			m.Weight = cast.ToInt(v)
 		case "name":
diff --git a/navigation/pagemenus.go b/navigation/pagemenus.go
index c0d809ee3..4d2c45767 100644
--- a/navigation/pagemenus.go
+++ b/navigation/pagemenus.go
@@ -50,9 +50,7 @@ func PageMenusFromPage(p Page) (PageMenus, error) {
 		return nil, nil
 	}
 
-	link := p.RelPermalink()
-
-	me := MenuEntry{Page: p, Name: p.LinkTitle(), Weight: p.Weight(), URL: link}
+	me := MenuEntry{Page: p, Name: p.LinkTitle(), Weight: p.Weight()}
 
 	// Could be the name of the menu to attach it to
 	mname, err := cast.ToStringE(ms)
@@ -81,7 +79,7 @@ func PageMenusFromPage(p Page) (PageMenus, error) {
 	}
 
 	for name, menu := range menus {
-		menuEntry := MenuEntry{Page: p, Name: p.LinkTitle(), URL: link, Weight: p.Weight(), Menu: name}
+		menuEntry := MenuEntry{Page: p, Name: p.LinkTitle(), Weight: p.Weight(), Menu: name}
 		if menu != nil {
 			ime, err := cast.ToStringMapE(menu)
 			if err != nil {
@@ -153,7 +151,7 @@ func (pm *pageMenus) HasMenuCurrent(menuID string, me *MenuEntry) bool {
 
 	// The following logic is kept from back when Hugo had both Page and Node types.
 	// TODO(bep) consolidate / clean
-	nme := MenuEntry{Page: pm.p, Name: pm.p.LinkTitle(), URL: pm.p.RelPermalink()}
+	nme := MenuEntry{Page: pm.p, Name: pm.p.LinkTitle()}
 
 	for _, child := range me.Children {
 		if nme.IsSameResource(child) {
@@ -183,7 +181,7 @@ func (pm *pageMenus) IsMenuCurrent(menuID string, inme *MenuEntry) bool {
 
 	// The following logic is kept from back when Hugo had both Page and Node types.
 	// TODO(bep) consolidate / clean
-	me := MenuEntry{Page: pm.p, Name: pm.p.LinkTitle(), URL: pm.p.RelPermalink()}
+	me := MenuEntry{Page: pm.p, Name: pm.p.LinkTitle()}
 
 	if !me.IsSameResource(inme) {
 		return false