Move all Kind constants to its own package

See #11256

7 files changed, 157 insertions, 76 deletions

diff --git a/resources/kinds/kinds.go b/resources/kinds/kinds.go
new file mode 100644
index 000000000..b1d1c18f4
--- /dev/null
+++ b/resources/kinds/kinds.go
@@ -0,0 +1,107 @@
+// Copyright 2023 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package kinds
+
+import (
+	"sort"
+	"strings"
+)
+
+const (
+	KindPage = "page"
+
+	// The rest are node types; home page, sections etc.
+
+	KindHome    = "home"
+	KindSection = "section"
+
+	// Note that before Hugo 0.73 these were confusingly named
+	// taxonomy (now: term)
+	// taxonomyTerm (now: taxonomy)
+	KindTaxonomy = "taxonomy"
+	KindTerm     = "term"
+
+	// The following are (currently) temporary nodes,
+	// i.e. nodes we create just to render in isolation.
+	KindRSS       = "rss"
+	KindSitemap   = "sitemap"
+	KindRobotsTXT = "robotstxt"
+	Kind404       = "404"
+)
+
+var (
+	// This is all the kinds we can expect to find in .Site.Pages.
+	AllKindsInPages []string
+	// This is all the kinds, including the temporary ones.
+	AllKinds []string
+)
+
+func init() {
+	for k := range kindMapMain {
+		AllKindsInPages = append(AllKindsInPages, k)
+		AllKinds = append(AllKinds, k)
+	}
+
+	for k := range kindMapTemporary {
+		AllKinds = append(AllKinds, k)
+	}
+
+	// Sort the slices for determinism.
+	sort.Strings(AllKindsInPages)
+	sort.Strings(AllKinds)
+}
+
+var kindMapMain = map[string]string{
+	KindPage:     KindPage,
+	KindHome:     KindHome,
+	KindSection:  KindSection,
+	KindTaxonomy: KindTaxonomy,
+	KindTerm:     KindTerm,
+
+	// Legacy, pre v0.53.0.
+	"taxonomyterm": KindTaxonomy,
+}
+
+var kindMapTemporary = map[string]string{
+	KindRSS:       KindRSS,
+	KindSitemap:   KindSitemap,
+	KindRobotsTXT: KindRobotsTXT,
+	Kind404:       Kind404,
+}
+
+// GetKindMain gets the page kind given a string, empty if not found.
+// Note that this will not return any temporary kinds (e.g. robotstxt).
+func GetKindMain(s string) string {
+	return kindMapMain[strings.ToLower(s)]
+}
+
+// GetKindAny gets the page kind given a string, empty if not found.
+func GetKindAny(s string) string {
+	if pkind := GetKindMain(s); pkind != "" {
+		return pkind
+	}
+	return kindMapTemporary[strings.ToLower(s)]
+}
+
+// IsDeprecated returns whether the given kind is deprecated.
+func IsDeprecated(s string) bool {
+	s = strings.ToLower(s)
+
+	switch s {
+	case "taxonomyterm":
+		return true
+	default:
+		return false
+	}
+}
diff --git a/resources/page/page_kinds_test.go b/resources/kinds/kinds_test.go
index 357be6739..c2868d617 100644
--- a/resources/page/page_kinds_test.go
+++ b/resources/kinds/kinds_test.go
@@ -1,4 +1,4 @@
-// Copyright 2019 The Hugo Authors. All rights reserved.
+// Copyright 2023 The Hugo Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package page
+package kinds
 
 import (
 	"testing"
@@ -29,9 +29,12 @@ func TestKind(t *testing.T) {
 	c.Assert(KindTaxonomy, qt.Equals, "taxonomy")
 	c.Assert(KindTerm, qt.Equals, "term")
 
-	c.Assert(GetKind("TAXONOMYTERM"), qt.Equals, KindTaxonomy)
-	c.Assert(GetKind("Taxonomy"), qt.Equals, KindTaxonomy)
-	c.Assert(GetKind("Page"), qt.Equals, KindPage)
-	c.Assert(GetKind("Home"), qt.Equals, KindHome)
-	c.Assert(GetKind("SEction"), qt.Equals, KindSection)
+	c.Assert(GetKindMain("TAXONOMYTERM"), qt.Equals, KindTaxonomy)
+	c.Assert(GetKindMain("Taxonomy"), qt.Equals, KindTaxonomy)
+	c.Assert(GetKindMain("Page"), qt.Equals, KindPage)
+	c.Assert(GetKindMain("Home"), qt.Equals, KindHome)
+	c.Assert(GetKindMain("SEction"), qt.Equals, KindSection)
+
+	c.Assert(GetKindAny("Page"), qt.Equals, KindPage)
+	c.Assert(GetKindAny("Robotstxt"), qt.Equals, KindRobotsTXT)
 }
diff --git a/resources/page/page_kinds.go b/resources/page/page_kinds.go
index 479859841..bb846ca5b 100644
--- a/resources/page/page_kinds.go
+++ b/resources/page/page_kinds.go
@@ -12,36 +12,3 @@
 // limitations under the License.
 
 package page
-
-import "strings"
-
-const (
-	KindPage = "page"
-
-	// The rest are node types; home page, sections etc.
-
-	KindHome    = "home"
-	KindSection = "section"
-
-	// Note that before Hugo 0.73 these were confusingly named
-	// taxonomy (now: term)
-	// taxonomyTerm (now: taxonomy)
-	KindTaxonomy = "taxonomy"
-	KindTerm     = "term"
-)
-
-var kindMap = map[string]string{
-	strings.ToLower(KindPage):     KindPage,
-	strings.ToLower(KindHome):     KindHome,
-	strings.ToLower(KindSection):  KindSection,
-	strings.ToLower(KindTaxonomy): KindTaxonomy,
-	strings.ToLower(KindTerm):     KindTerm,
-
-	// Legacy, pre v0.53.0.
-	"taxonomyterm": KindTaxonomy,
-}
-
-// GetKind gets the page kind given a string, empty if not found.
-func GetKind(s string) string {
-	return kindMap[strings.ToLower(s)]
-}
diff --git a/resources/page/page_matcher.go b/resources/page/page_matcher.go
index a2b327f61..4c861cbd7 100644
--- a/resources/page/page_matcher.go
+++ b/resources/page/page_matcher.go
@@ -21,6 +21,7 @@ import (
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/hugofs/glob"
+	"github.com/gohugoio/hugo/resources/kinds"
 	"github.com/mitchellh/mapstructure"
 )
 
@@ -173,7 +174,7 @@ func decodePageMatcher(m any, v *PageMatcher) error {
 	if v.Kind != "" {
 		g, _ := glob.GetGlob(v.Kind)
 		found := false
-		for _, k := range kindMap {
+		for _, k := range kinds.AllKindsInPages {
 			if g.Match(k) {
 				found = true
 				break
diff --git a/resources/page/page_paths.go b/resources/page/page_paths.go
index 0ed758ca1..1bc16fe35 100644
--- a/resources/page/page_paths.go
+++ b/resources/page/page_paths.go
@@ -21,6 +21,7 @@ import (
 	"github.com/gohugoio/hugo/common/urls"
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/output"
+	"github.com/gohugoio/hugo/resources/kinds"
 )
 
 const slash = "/"
@@ -147,7 +148,7 @@ func CreateTargetPaths(d TargetPathDescriptor) (tp TargetPaths) {
 		isUgly = true
 	}
 
-	if d.Kind != KindPage && d.URL == "" && len(d.Sections) > 0 {
+	if d.Kind != kinds.KindPage && d.URL == "" && len(d.Sections) > 0 {
 		if d.ExpandedPermalink != "" {
 			pagePath = pjoin(pagePath, d.ExpandedPermalink)
 		} else {
@@ -160,7 +161,7 @@ func CreateTargetPaths(d TargetPathDescriptor) (tp TargetPaths) {
 		pagePath = pjoin(pagePath, d.Type.Path)
 	}
 
-	if d.Kind != KindHome && d.URL != "" {
+	if d.Kind != kinds.KindHome && d.URL != "" {
 		pagePath = pjoin(pagePath, d.URL)
 
 		if d.Addends != "" {
@@ -200,7 +201,7 @@ func CreateTargetPaths(d TargetPathDescriptor) (tp TargetPaths) {
 			}
 		}
 
-	} else if d.Kind == KindPage {
+	} else if d.Kind == kinds.KindPage {
 
 		if d.ExpandedPermalink != "" {
 			pagePath = pjoin(pagePath, d.ExpandedPermalink)
@@ -307,7 +308,7 @@ func CreateTargetPaths(d TargetPathDescriptor) (tp TargetPaths) {
 
 	// if page URL is explicitly set in frontmatter,
 	// preserve its value without sanitization
-	if d.Kind != KindPage || d.URL == "" {
+	if d.Kind != kinds.KindPage || d.URL == "" {
 		// Note: MakePathSanitized will lower case the path if
 		// disablePathToLower isn't set.
 		pagePath = d.PathSpec.MakePathSanitized(pagePath)
diff --git a/resources/page/page_paths_test.go b/resources/page/page_paths_test.go
index 137f3bec3..dd6457f77 100644
--- a/resources/page/page_paths_test.go
+++ b/resources/page/page_paths_test.go
@@ -20,6 +20,7 @@ import (
 	"testing"
 
 	"github.com/gohugoio/hugo/media"
+	"github.com/gohugoio/hugo/resources/kinds"
 	"github.com/gohugoio/hugo/resources/page"
 
 	"github.com/gohugoio/hugo/output"
@@ -47,31 +48,31 @@ func TestPageTargetPath(t *testing.T) {
 					d        page.TargetPathDescriptor
 					expected page.TargetPaths
 				}{
-					{"JSON home", page.TargetPathDescriptor{Kind: page.KindHome, Type: output.JSONFormat}, page.TargetPaths{TargetFilename: "/index.json", SubResourceBaseTarget: "", Link: "/index.json"}},
-					{"AMP home", page.TargetPathDescriptor{Kind: page.KindHome, Type: output.AMPFormat}, page.TargetPaths{TargetFilename: "/amp/index.html", SubResourceBaseTarget: "/amp", Link: "/amp/"}},
-					{"HTML home", page.TargetPathDescriptor{Kind: page.KindHome, BaseName: "_index", Type: output.HTMLFormat}, page.TargetPaths{TargetFilename: "/index.html", SubResourceBaseTarget: "", Link: "/"}},
-					{"Netlify redirects", page.TargetPathDescriptor{Kind: page.KindHome, BaseName: "_index", Type: noExtDelimFormat}, page.TargetPaths{TargetFilename: "/_redirects", SubResourceBaseTarget: "", Link: "/_redirects"}},
+					{"JSON home", page.TargetPathDescriptor{Kind: kinds.KindHome, Type: output.JSONFormat}, page.TargetPaths{TargetFilename: "/index.json", SubResourceBaseTarget: "", Link: "/index.json"}},
+					{"AMP home", page.TargetPathDescriptor{Kind: kinds.KindHome, Type: output.AMPFormat}, page.TargetPaths{TargetFilename: "/amp/index.html", SubResourceBaseTarget: "/amp", Link: "/amp/"}},
+					{"HTML home", page.TargetPathDescriptor{Kind: kinds.KindHome, BaseName: "_index", Type: output.HTMLFormat}, page.TargetPaths{TargetFilename: "/index.html", SubResourceBaseTarget: "", Link: "/"}},
+					{"Netlify redirects", page.TargetPathDescriptor{Kind: kinds.KindHome, BaseName: "_index", Type: noExtDelimFormat}, page.TargetPaths{TargetFilename: "/_redirects", SubResourceBaseTarget: "", Link: "/_redirects"}},
 					{"HTML section list", page.TargetPathDescriptor{
-						Kind:     page.KindSection,
+						Kind:     kinds.KindSection,
 						Sections: []string{"sect1"},
 						BaseName: "_index",
 						Type:     output.HTMLFormat,
 					}, page.TargetPaths{TargetFilename: "/sect1/index.html", SubResourceBaseTarget: "/sect1", Link: "/sect1/"}},
 					{"HTML taxonomy term", page.TargetPathDescriptor{
-						Kind:     page.KindTerm,
+						Kind:     kinds.KindTerm,
 						Sections: []string{"tags", "hugo"},
 						BaseName: "_index",
 						Type:     output.HTMLFormat,
 					}, page.TargetPaths{TargetFilename: "/tags/hugo/index.html", SubResourceBaseTarget: "/tags/hugo", Link: "/tags/hugo/"}},
 					{"HTML taxonomy", page.TargetPathDescriptor{
-						Kind:     page.KindTaxonomy,
+						Kind:     kinds.KindTaxonomy,
 						Sections: []string{"tags"},
 						BaseName: "_index",
 						Type:     output.HTMLFormat,
 					}, page.TargetPaths{TargetFilename: "/tags/index.html", SubResourceBaseTarget: "/tags", Link: "/tags/"}},
 					{
 						"HTML page", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/a/b",
 							BaseName: "mypage",
 							Sections: []string{"a"},
@@ -81,7 +82,7 @@ func TestPageTargetPath(t *testing.T) {
 
 					{
 						"HTML page with index as base", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/a/b",
 							BaseName: "index",
 							Sections: []string{"a"},
@@ -91,7 +92,7 @@ func TestPageTargetPath(t *testing.T) {
 
 					{
 						"HTML page with special chars", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/a/b",
 							BaseName: "My Page!",
 							Type:     output.HTMLFormat,
@@ -105,7 +106,7 @@ func TestPageTargetPath(t *testing.T) {
 					}, page.TargetPaths{TargetFilename: "/sect1/index.xml", SubResourceBaseTarget: "/sect1", Link: "/sect1/index.xml"}},
 					{
 						"AMP page", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/a/b/c",
 							BaseName: "myamp",
 							Type:     output.AMPFormat,
@@ -113,7 +114,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"AMP page with URL with suffix", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/sect/",
 							BaseName: "mypage",
 							URL:      "/some/other/url.xhtml",
@@ -122,7 +123,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"JSON page with URL without suffix", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/sect/",
 							BaseName: "mypage",
 							URL:      "/some/other/path/",
@@ -131,7 +132,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"JSON page with URL without suffix and no trailing slash", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/sect/",
 							BaseName: "mypage",
 							URL:      "/some/other/path",
@@ -140,7 +141,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"HTML page with URL without suffix and no trailing slash", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/sect/",
 							BaseName: "mypage",
 							URL:      "/some/other/path",
@@ -149,7 +150,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"HTML page with URL containing double hyphen", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/sect/",
 							BaseName: "mypage",
 							URL:      "/some/other--url/",
@@ -158,7 +159,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"HTML page with expanded permalink", page.TargetPathDescriptor{
-							Kind:              page.KindPage,
+							Kind:              kinds.KindPage,
 							Dir:               "/a/b",
 							BaseName:          "mypage",
 							ExpandedPermalink: "/2017/10/my-title/",
@@ -167,7 +168,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"Paginated HTML home", page.TargetPathDescriptor{
-							Kind:     page.KindHome,
+							Kind:     kinds.KindHome,
 							BaseName: "_index",
 							Type:     output.HTMLFormat,
 							Addends:  "page/3",
@@ -175,7 +176,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"Paginated Taxonomy terms list", page.TargetPathDescriptor{
-							Kind:     page.KindTerm,
+							Kind:     kinds.KindTerm,
 							BaseName: "_index",
 							Sections: []string{"tags", "hugo"},
 							Type:     output.HTMLFormat,
@@ -184,7 +185,7 @@ func TestPageTargetPath(t *testing.T) {
 					},
 					{
 						"Regular page with addend", page.TargetPathDescriptor{
-							Kind:     page.KindPage,
+							Kind:     kinds.KindPage,
 							Dir:      "/a/b",
 							BaseName: "mypage",
 							Addends:  "c/d/e",
@@ -207,8 +208,8 @@ func TestPageTargetPath(t *testing.T) {
 							expected := test.expected
 
 							// TODO(bep) simplify
-							if test.d.Kind == page.KindPage && test.d.BaseName == test.d.Type.BaseName {
-							} else if test.d.Kind == page.KindHome && test.d.Type.Path != "" {
+							if test.d.Kind == kinds.KindPage && test.d.BaseName == test.d.Type.BaseName {
+							} else if test.d.Kind == kinds.KindHome && test.d.Type.Path != "" {
 							} else if test.d.Type.MediaType.FirstSuffix.Suffix != "" && (!strings.HasPrefix(expected.TargetFilename, "/index") || test.d.Addends != "") && test.d.URL == "" && isUgly {
 								expected.TargetFilename = strings.Replace(expected.TargetFilename,
 									"/"+test.d.Type.BaseName+"."+test.d.Type.MediaType.FirstSuffix.Suffix,
@@ -250,12 +251,12 @@ func TestPageTargetPathPrefix(t *testing.T) {
 	}{
 		{
 			"URL set, prefix both, no force",
-			page.TargetPathDescriptor{Kind: page.KindPage, Type: output.JSONFormat, URL: "/mydir/my.json", ForcePrefix: false, PrefixFilePath: "pf", PrefixLink: "pl"},
+			page.TargetPathDescriptor{Kind: kinds.KindPage, Type: output.JSONFormat, URL: "/mydir/my.json", ForcePrefix: false, PrefixFilePath: "pf", PrefixLink: "pl"},
 			page.TargetPaths{TargetFilename: "/mydir/my.json", SubResourceBaseTarget: "/mydir", SubResourceBaseLink: "/mydir", Link: "/mydir/my.json"},
 		},
 		{
 			"URL set, prefix both, force",
-			page.TargetPathDescriptor{Kind: page.KindPage, Type: output.JSONFormat, URL: "/mydir/my.json", ForcePrefix: true, PrefixFilePath: "pf", PrefixLink: "pl"},
+			page.TargetPathDescriptor{Kind: kinds.KindPage, Type: output.JSONFormat, URL: "/mydir/my.json", ForcePrefix: true, PrefixFilePath: "pf", PrefixLink: "pl"},
 			page.TargetPaths{TargetFilename: "/pf/mydir/my.json", SubResourceBaseTarget: "/pf/mydir", SubResourceBaseLink: "/pl/mydir", Link: "/pl/mydir/my.json"},
 		},
 	}
diff --git a/resources/page/permalinks.go b/resources/page/permalinks.go
index 3b12e1154..7fc55eccb 100644
--- a/resources/page/permalinks.go
+++ b/resources/page/permalinks.go
@@ -27,6 +27,7 @@ import (
 
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/helpers"
+	"github.com/gohugoio/hugo/resources/kinds"
 )
 
 // PermalinkExpander holds permalin mappings per section.
@@ -398,16 +399,16 @@ func (l PermalinkExpander) toSliceFunc(cut string) func(s []string) []string {
 
 }
 
-var permalinksKindsSuppurt = []string{KindPage, KindSection, KindTaxonomy, KindTerm}
+var permalinksKindsSuppurt = []string{kinds.KindPage, kinds.KindSection, kinds.KindTaxonomy, kinds.KindTerm}
 
 // DecodePermalinksConfig decodes the permalinks configuration in the given map
 func DecodePermalinksConfig(m map[string]any) (map[string]map[string]string, error) {
 	permalinksConfig := make(map[string]map[string]string)
 
-	permalinksConfig[KindPage] = make(map[string]string)
-	permalinksConfig[KindSection] = make(map[string]string)
-	permalinksConfig[KindTaxonomy] = make(map[string]string)
-	permalinksConfig[KindTerm] = make(map[string]string)
+	permalinksConfig[kinds.KindPage] = make(map[string]string)
+	permalinksConfig[kinds.KindSection] = make(map[string]string)
+	permalinksConfig[kinds.KindTaxonomy] = make(map[string]string)
+	permalinksConfig[kinds.KindTerm] = make(map[string]string)
 
 	config := maps.CleanConfigStringMap(m)
 	for k, v := range config {
@@ -417,8 +418,8 @@ func DecodePermalinksConfig(m map[string]any) (map[string]map[string]string, err
 			//   key = '...'
 
 			// To sucessfully be backward compatible, "default" patterns need to be set for both page and term
-			permalinksConfig[KindPage][k] = v
-			permalinksConfig[KindTerm][k] = v
+			permalinksConfig[kinds.KindPage][k] = v
+			permalinksConfig[kinds.KindTerm][k] = v
 
 		case maps.Params:
 			// [permalinks.key]