For multiple dimensions setups, fix alias handling and multihost publish path

* The alias handling was left as is when we added new dimensions in v0.152.0, which meant that if you had `defaultContentVersionInSubDir=true` set, the alias page in the root would not be correctly created.
* Also, if you had multihost setup with multiple dimensions, the publish would be incorrect: The language key was added last instead of first.
* The home page alias handling is reworked and made more robust, which also fixes some subtle issues:

* It now supports redircects for multiple HTML output formats for the home page.
* We skip creating aliases for disabled home pages.
* With potentially multiple output formats with one of them canonical, we added a new  `Canonical` method to the `Page.OutputFormats`, which allows you to do this in a template:

```handlebars
{{ with .OutputFormats.Canonical }}<link rel="{{ .Rel }}" href="{{ .Permalink }}">{{ end }}
```

Fixes #14354
Fixes #14356

config/allconfig/allconfig.go

@@ -607,8 +607,13 @@ type RootConfig struct {
 	DefaultOutputFormat string
 
 	// Disable generation of redirect to the default language when DefaultContentLanguageInSubdir is enabled.
+	// Note that this currently is an alias for DisableDefaultDimensionRedirect introduced in v0.154.4.
+	// It's not obvious how a more fine grained setup would work.
 	DisableDefaultLanguageRedirect bool
 
+	// Disable generation of redirect to the default dimension when DefaultContentRoleInSubdir or DefaultContentVersionInSubdir or DefaultContentLanguageInSubdir is enabled.
+	DisableDefaultDimensionRedirect bool
+
 	// Disable creation of alias redirect pages.
 	DisableAliases bool
 

hugolib/alias.go

@@ -70,6 +70,10 @@ func (a aliasHandler) renderAlias(permalink string, p page.Page, matrix sitesmat
 		return nil, errors.New("no alias template found")
 	}
 
+	if p == nil {
+		p = page.NopPage
+	}
+
 	data := aliasPage{
 		permalink,
 		p,

hugolib/page__paths.go

@@ -160,11 +160,19 @@ func createTargetPathDescriptor(p *pageState) (page.TargetPathDescriptor, error)
 
 	// Add path prefixes.
 	// Add any role first, as that is a natural candidate for external ACL checks.
+	// For multihost sites, the file path needs to start with the language code.
+	if s.h.Conf.IsMultihost() {
+		addPrefix(s.getLanguageTargetPathLang(true), "")
+	}
 	rolePrefix := s.getPrefixRole()
 	addPrefix(rolePrefix, rolePrefix)
 	versionPrefix := s.getPrefixVersion()
 	addPrefix(versionPrefix, versionPrefix)
-	addPrefix(s.getLanguageTargetPathLang(alwaysInSubDir), s.getLanguagePermalinkLang(alwaysInSubDir))
+	if s.h.Conf.IsMultihost() {
+		addPrefix("", s.getLanguagePermalinkLang(alwaysInSubDir))
+	} else {
+		addPrefix(s.getLanguageTargetPathLang(alwaysInSubDir), s.getLanguagePermalinkLang(alwaysInSubDir))
+	}
 
 	if desc.URL != "" && strings.IndexByte(desc.URL, ':') >= 0 {
 		// Attempt to parse and expand an url

hugolib/site.go

@@ -1056,7 +1056,7 @@ func (s *siteRefLinker) refLink(ref string, source any, relative bool, outputFor
 		if outputFormat != "" {
 			o := target.OutputFormats().Get(outputFormat)
 
-			if o == nil {
+			if o.IsZero() {
 				s.logNotFound(refURL.Path, fmt.Sprintf("output format %q", outputFormat), p, pos)
 				return s.notFoundURL, nil
 			}
@@ -1770,10 +1770,6 @@ func (s *Site) render(ctx *siteRenderContext) (err error) {
 		return
 	}
 
-	if err = s.renderMainLanguageRedirect(); err != nil {
-		return
-	}
-
 	return
 }
 

hugolib/site_render.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/bep/logg"
 	"github.com/gohugoio/go-radix"
+	"github.com/gohugoio/hugo/common/paths"
 	"github.com/gohugoio/hugo/hugolib/doctree"
 	"github.com/gohugoio/hugo/tpl/tplimpl"
 
@@ -202,6 +203,16 @@ func pageRenderer(
 			}
 		}
 
+		if p.IsHome() && p.outputFormat().IsHTML && s.siteVector.IsFirst() {
+			if err = s.renderDefaultDimensionRedirect(p); err != nil {
+				if sendErr(err) {
+					continue
+				} else {
+					return
+				}
+			}
+		}
+
 		if p.paginator != nil && p.paginator.current != nil {
 			if err := s.renderPaginator(p, templ); err != nil {
 				if sendErr(err) {
@@ -357,32 +368,51 @@ func (s *Site) renderAliases() error {
 	return w.Walk(context.TODO())
 }
 
-// renderMainLanguageRedirect creates a redirect to the main language home,
+// renderDefaultDimensionRedirect creates a redirect to the main dimension's home,
 // depending on if it lives in sub folder (e.g. /en) or not.
-func (s *Site) renderMainLanguageRedirect() error {
-	if s.conf.DisableDefaultLanguageRedirect {
-		return nil
-	}
-	if s.h.Conf.IsMultihost() || !(s.h.Conf.DefaultContentLanguageInSubdir() || s.h.Conf.IsMultilingual()) {
-		// No need for a redirect
+func (s *Site) renderDefaultDimensionRedirect(home *pageState) error {
+	if s.conf.DisableDefaultLanguageRedirect || s.conf.DisableDefaultDimensionRedirect {
 		return nil
 	}
 
-	html, found := s.conf.OutputFormats.Config.GetByName("html")
-	if found {
-		mainLang := s.conf.DefaultContentLanguage
-		if s.conf.DefaultContentLanguageInSubdir {
-			mainLangURL := s.PathSpec.AbsURL(mainLang+"/", false)
-			s.Log.Debugf("Write redirect to main language %s: %s", mainLang, mainLangURL)
-			if err := s.publishDestAlias(true, "/", mainLangURL, html, nil); err != nil {
-				return err
-			}
-		} else {
-			mainLangURL := s.PathSpec.AbsURL("", false)
-			s.Log.Debugf("Write redirect to main language %s: %s", mainLang, mainLangURL)
-			if err := s.publishDestAlias(true, mainLang, mainLangURL, html, nil); err != nil {
-				return err
-			}
+	shouldAdd := s.conf.DefaultContentLanguageInSubdir && !s.Conf.IsMultihost()
+	shouldAdd = shouldAdd || s.conf.DefaultContentVersionInSubdir || s.conf.DefaultContentRoleInSubdir
+	if !shouldAdd {
+		return nil
+	}
+
+	homeLink := home.pageOutput.targetPaths().Link // This doesn't have any baseURL paths in it.
+
+	of := home.outputFormat()
+	homePermalink := home.Permalink()
+
+	var ps []string
+	if of.Path != "" {
+		// For OutputFormats with a path, creating more than one alias will easily create path clashes without much value.
+		ps = []string{paths.AddLeadingAndTrailingSlash(of.Path)}
+	} else {
+		ps = []string{"/"}
+		// /guest/v1.0.0/en/
+		//    /,/guest/,/guest/v1.0.0  = /guest/v1.0.0/en/
+		// /guest/v1.0.0/
+		//    /,/guest/ =  /guest/v1.0.0/
+		parts := strings.Split(strings.Trim(homeLink, "/"), "/")
+
+		for i := 0; i < len(parts)-1; i++ {
+			ps = append(ps, paths.AddLeadingAndTrailingSlash(strings.Join(parts[0:i+1], "/")))
+		}
+	}
+
+	if s.h.Configs.IsMultihost {
+		prefix := "/" + s.LanguagePrefix()
+		for i, p := range ps {
+			ps[i] = path.Join(prefix, p)
+		}
+	}
+
+	for _, p := range ps {
+		if err := s.publishDestAlias(true, p, homePermalink, of, home); err != nil {
+			return err
 		}
 	}
 

hugolib/sitesmatrix/sitematrix_integration_test.go

@@ -1272,3 +1272,115 @@ disableKinds = ["rss", "sitemap", "taxonomy", "term"]
 		b.AssertFileContent("public/s1/index.html", "section|/s1/|")
 	}
 }
+
+const defaultContentDimensionRedirectsFiletemplate = `
+-- hugo.toml --
+baseURL = "BASE_URL_PLACEHOLDER"
+disableKinds = ["sitemap", "taxonomy", "term"]
+defaultContentLanguageInSubDir = true
+defaultContentVersionInSubDir = true
+defaultContentRoleInSubDir = true
+disableDefaultLanguageRedirect = false
+disableDefaultDimensionRedirect = false
+defaultContentLanguage = "en"
+[outputs]
+home = [ 'rss', 'amp', 'html']
+-- layouts/home.html --
+Home.
+`
+
+// Issue 14354
+func TestSitesMatrixRedirects(t *testing.T) {
+	t.Parallel()
+
+	files := strings.ReplaceAll(defaultContentDimensionRedirectsFiletemplate, "BASE_URL_PLACEHOLDER", "https://example.org/")
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/index.html", "url=https://example.org/guest/v1.0.0/en/\"", `<link rel="canonical" href="https://example.org/guest/v1.0.0/en/">`)
+	b.AssertFileContent("public/amp/index.html", "url=https://example.org/guest/v1.0.0/en/amp/\"", `<link rel="canonical" href="https://example.org/guest/v1.0.0/en/">`)
+	b.AssertFileContent("public/guest/index.html", "url=https://example.org/guest/v1.0.0/en/\"")
+	b.AssertFileContent("public/guest/v1.0.0/index.html", "url=https://example.org/guest/v1.0.0/en/\"")
+	b.AssertFileContent("public/guest/v1.0.0/en/index.html", "Home.")
+	b.AssertFileContent("public/guest/v1.0.0/en/amp/index.html", "Home.")
+}
+
+func TestSitesMatrixRedirectsBasePathInBaseURL(t *testing.T) {
+	t.Parallel()
+
+	files := strings.ReplaceAll(defaultContentDimensionRedirectsFiletemplate, "BASE_URL_PLACEHOLDER", "https://example.org/docs/")
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/index.html", "url=https://example.org/docs/guest/v1.0.0/en/\"")
+	b.AssertFileContent("public/amp/index.html", "url=https://example.org/docs/guest/v1.0.0/en/amp/\"", `<link rel="canonical" href="https://example.org/docs/guest/v1.0.0/en/">`)
+	b.AssertFileContent("public/guest/index.html", "url=https://example.org/docs/guest/v1.0.0/en/\"")
+	b.AssertFileContent("public/guest/v1.0.0/index.html", "url=https://example.org/docs/guest/v1.0.0/en/\"")
+	b.AssertFileContent("public/guest/v1.0.0/en/index.html", "Home.")
+}
+
+func TestSitesMatrixRedirectsDisableDefaultLanguageRedirect(t *testing.T) {
+	t.Parallel()
+
+	files := strings.ReplaceAll(defaultContentDimensionRedirectsFiletemplate, "BASE_URL_PLACEHOLDER", "https://example.org/")
+
+	runTest := func(files string) {
+		b := hugolib.Test(t, files)
+
+		b.AssertFileExists("public/index.html", false)
+		b.AssertFileExists("public/guest/index.html", false)
+		b.AssertFileExists("public/guest/v1.0.0/index.html", false)
+		b.AssertFileContent("public/guest/v1.0.0/en/index.html", "Home.")
+	}
+
+	runTest(strings.ReplaceAll(files, "disableDefaultLanguageRedirect = false", "disableDefaultLanguageRedirect = true"))
+	runTest(strings.ReplaceAll(files, "disableDefaultDimensionRedirect = false", "disableDefaultDimensionRedirect = true"))
+}
+
+func TestSitesMatrixRedirectsDefaultContentVersionInBase(t *testing.T) {
+	t.Parallel()
+
+	files := strings.ReplaceAll(defaultContentDimensionRedirectsFiletemplate, "BASE_URL_PLACEHOLDER", "https://example.org/")
+	files = strings.ReplaceAll(files, "defaultContentVersionInSubDir = true", "defaultContentVersionInSubDir = false")
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/index.html", "url=https://example.org/guest/en/\"")
+	b.AssertFileContent("public/guest/index.html", "url=https://example.org/guest/en/\"")
+	b.AssertFileExists("public/guest/v1.0.0/index.html", false)
+	b.AssertFileContent("public/guest/en/index.html", "Home.")
+}
+
+func TestSitesMatrixRedirectsMultiHost(t *testing.T) {
+	t.Parallel()
+	//
+	files := `
+-- hugo.toml --
+disableKinds = ["sitemap", "taxonomy", "term"]
+defaultContentLanguageInSubDir = true
+defaultContentVersionInSubDir = true
+defaultContentRoleInSubDir = true
+disableDefaultLanguageRedirect = false
+disableDefaultDimensionRedirect = false
+defaultContentLanguage = "en"
+[languages]
+[languages.en]
+weight = 1
+baseURL = "https://en.example.org/"
+[languages.nn]
+weight = 2
+baseURL = "https://nn.example.org/"
+[outputs]
+home = [ 'rss', 'amp', 'html']
+-- layouts/home.html --
+Home.
+`
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/en/index.html", "url=https://en.example.org/guest/v1.0.0/\"", `<link rel="canonical" href="https://en.example.org/guest/v1.0.0/">`)
+	b.AssertFileContent("public/en/amp/index.html", "url=https://en.example.org/guest/v1.0.0/amp/\"", `<link rel="canonical" href="https://en.example.org/guest/v1.0.0/">`)
+	b.AssertFileContent("public/en/guest/index.html", "url=https://en.example.org/guest/v1.0.0/\"")
+	b.AssertFileContent("public/en/guest/v1.0.0/index.html", "Home.")
+	b.AssertFileContent("public/en/guest/v1.0.0/amp/index.html", "Home.")
+}

resources/page/page_outputformat.go

@@ -18,6 +18,7 @@ package page
 import (
 	"strings"
 
+	"github.com/gohugoio/hugo/common/types"
 	"github.com/gohugoio/hugo/media"
 	"github.com/gohugoio/hugo/output"
 )
@@ -25,6 +26,8 @@ import (
 // OutputFormats holds a list of the relevant output formats for a given page.
 type OutputFormats []OutputFormat
 
+var _ types.Zeroer = OutputFormat{}
+
 // OutputFormat links to a representation of a resource.
 type OutputFormat struct {
 	// Rel contains a value that can be used to construct a rel link.
@@ -65,6 +68,11 @@ func (o OutputFormat) RelPermalink() string {
 	return o.relPermalink
 }
 
+// IsZero checks whether this OutputFormat is the zero value.
+func (o OutputFormat) IsZero() bool {
+	return o.Format.Name == ""
+}
+
 func NewOutputFormat(relPermalink, permalink string, isCanonical bool, f output.Format) OutputFormat {
 	isUserConfigured := true
 	for _, d := range output.DefaultFormats {
@@ -84,12 +92,24 @@ func NewOutputFormat(relPermalink, permalink string, isCanonical bool, f output.
 }
 
 // Get gets a OutputFormat given its name, i.e. json, html etc.
-// It returns nil if none found.
-func (o OutputFormats) Get(name string) *OutputFormat {
+// It returns a zero OutputFormat if not found.
+func (o OutputFormats) Get(name string) OutputFormat {
 	for _, f := range o {
 		if strings.EqualFold(f.Format.Name, name) {
-			return &f
+			return f
 		}
 	}
-	return nil
+	return OutputFormat{}
+}
+
+// Canonical returns the first canonical OutputFormat for this page,
+// or a zero OutputFormat if not found.
+func (o OutputFormats) Canonical() OutputFormat {
+	const canonical = "canonical"
+	for _, f := range o {
+		if strings.EqualFold(f.Rel, canonical) {
+			return f
+		}
+	}
+	return OutputFormat{}
 }

resources/page/page_paths.go

@@ -432,6 +432,7 @@ func (p *pagePathBuilder) PathDirBase() string {
 
 func (p *pagePathBuilder) PathFile() string {
 	dir := p.Path(0)
+
 	if p.prefixPath != "" {
 		dir = "/" + p.prefixPath + dir
 	}

tpl/tplimpl/embedded/templates/alias.html

@@ -1,9 +1,9 @@
-<!DOCTYPE html>
+<!doctype html>
 <html lang="{{ site.Language.LanguageCode }}">
   <head>
     <title>{{ .Permalink }}</title>
-    <link rel="canonical" href="{{ .Permalink }}">
-    <meta charset="utf-8">
+    {{ with .OutputFormats.Canonical }}<link rel="{{ .Rel }}" href="{{ .Permalink }}">{{ end }}
+    <meta charset="utf-8" />
     <meta http-equiv="refresh" content="0; url={{ .Permalink }}">
   </head>
 </html>