Reimplement and simplify Hugo's template system

See #13541 for details.

Fixes #13545
Fixes #13515
Closes #7964
Closes #13365
Closes #12988
Closes #4891

media/builtin.go

@@ -5,6 +5,7 @@ type BuiltinTypes struct {
 	CSSType        Type
 	SCSSType       Type
 	SASSType       Type
+	GotmplType     Type
 	CSVType        Type
 	HTMLType       Type
 	JavascriptType Type
@@ -60,6 +61,7 @@ var Builtin = BuiltinTypes{
 	CSSType:        Type{Type: "text/css"},
 	SCSSType:       Type{Type: "text/x-scss"},
 	SASSType:       Type{Type: "text/x-sass"},
+	GotmplType:     Type{Type: "text/x-gotmpl"},
 	CSVType:        Type{Type: "text/csv"},
 	HTMLType:       Type{Type: "text/html"},
 	JavascriptType: Type{Type: "text/javascript"},
@@ -121,6 +123,7 @@ var defaultMediaTypesConfig = map[string]any{
 	"text/typescript": map[string]any{"suffixes": []string{"ts"}},
 	"text/tsx":        map[string]any{"suffixes": []string{"tsx"}},
 	"text/jsx":        map[string]any{"suffixes": []string{"jsx"}},
+	"text/x-gotmpl":   map[string]any{"suffixes": []string{"gotmpl"}},
 
 	"application/json":          map[string]any{"suffixes": []string{"json"}},
 	"application/manifest+json": map[string]any{"suffixes": []string{"webmanifest"}},

media/config.go

@@ -17,6 +17,7 @@ import (
 	"fmt"
 	"path/filepath"
 	"reflect"
+	"slices"
 	"sort"
 	"strings"
 
@@ -26,7 +27,6 @@ import (
 
 	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/cast"
-	"slices"
 )
 
 // DefaultTypes is the default media types supported by Hugo.
@@ -271,4 +271,7 @@ var DefaultPathParser = &paths.PathParser{
 	IsContentExt: func(ext string) bool {
 		panic("not supported")
 	},
+	IsOutputFormat: func(name, ext string) bool {
+		panic("DefaultPathParser: not supported")
+	},
 }

media/config_test.go

@@ -151,5 +151,5 @@ func TestDefaultTypes(t *testing.T) {
 
 	}
 
-	c.Assert(len(DefaultTypes), qt.Equals, 40)
+	c.Assert(len(DefaultTypes), qt.Equals, 41)
 }

media/mediaType.go

@@ -282,7 +282,7 @@ func (t Types) BySuffix(suffix string) []Type {
 	suffix = t.normalizeSuffix(suffix)
 	var types []Type
 	for _, tt := range t {
-		if tt.hasSuffix(suffix) {
+		if tt.HasSuffix(suffix) {
 			types = append(types, tt)
 		}
 	}
@@ -293,7 +293,7 @@ func (t Types) BySuffix(suffix string) []Type {
 func (t Types) GetFirstBySuffix(suffix string) (Type, SuffixInfo, bool) {
 	suffix = t.normalizeSuffix(suffix)
 	for _, tt := range t {
-		if tt.hasSuffix(suffix) {
+		if tt.HasSuffix(suffix) {
 			return tt, SuffixInfo{
 				FullSuffix: tt.Delimiter + suffix,
 				Suffix:     suffix,
@@ -310,7 +310,7 @@ func (t Types) GetFirstBySuffix(suffix string) (Type, SuffixInfo, bool) {
 func (t Types) GetBySuffix(suffix string) (tp Type, si SuffixInfo, found bool) {
 	suffix = t.normalizeSuffix(suffix)
 	for _, tt := range t {
-		if tt.hasSuffix(suffix) {
+		if tt.HasSuffix(suffix) {
 			if found {
 				// ambiguous
 				found = false
@@ -330,14 +330,14 @@ func (t Types) GetBySuffix(suffix string) (tp Type, si SuffixInfo, found bool) {
 func (t Types) IsTextSuffix(suffix string) bool {
 	suffix = t.normalizeSuffix(suffix)
 	for _, tt := range t {
-		if tt.hasSuffix(suffix) {
+		if tt.HasSuffix(suffix) {
 			return tt.IsText()
 		}
 	}
 	return false
 }
 
-func (m Type) hasSuffix(suffix string) bool {
+func (m Type) HasSuffix(suffix string) bool {
 	return strings.Contains(","+m.SuffixesCSV+",", ","+suffix+",")
 }