Create lightweight forks of text/template and html/template

This commit also removes support for Ace and Amber templates.

Updates #6594

scripts/fork_go_templates/main.go

@@ -0,0 +1,207 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/gohugoio/hugo/common/hugio"
+
+	"github.com/spf13/afero"
+)
+
+func main() {
+	// TODO(bep) git checkout tag
+	// The current is built with Go version 9341fe073e6f7742c9d61982084874560dac2014 / go1.13.5
+	fmt.Println("Forking ...")
+	defer fmt.Println("Done ...")
+
+	cleanFork()
+
+	htmlRoot := filepath.Join(forkRoot, "htmltemplate")
+
+	for _, pkg := range goPackages {
+		copyGoPackage(pkg.dstPkg, pkg.srcPkg)
+	}
+
+	for _, pkg := range goPackages {
+		doWithGoFiles(pkg.dstPkg, pkg.rewriter, pkg.replacer)
+	}
+
+	goimports(htmlRoot)
+	gofmt(forkRoot)
+
+}
+
+const (
+	// TODO(bep)
+	goSource = "/Users/bep/dev/go/dump/go/src"
+	forkRoot = "../../tpl/internal/go_templates"
+)
+
+type goPackage struct {
+	srcPkg   string
+	dstPkg   string
+	replacer func(name, content string) string
+	rewriter func(name string)
+}
+
+var (
+	textTemplateReplacers = strings.NewReplacer(
+		`"text/template/`, `"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/`,
+		`"internal/fmtsort"`, `"github.com/gohugoio/hugo/tpl/internal/go_templates/fmtsort"`,
+		// Rename types and function that we want to overload.
+		"type state struct", "type stateOld struct",
+	)
+
+	htmlTemplateReplacers = strings.NewReplacer(
+		`. "html/template"`, `. "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"`,
+		`"html/template"`, `template "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"`,
+		"\"text/template\"\n", "template \"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate\"\n",
+		`"html/template"`, `htmltemplate "html/template"`,
+		`"fmt"`, `htmltemplate "html/template"`,
+	)
+)
+
+func commonReplace(name, content string) string {
+	if strings.HasSuffix(name, "_test.go") {
+		content = strings.Replace(content, "package template\n", `// +build go1.13,!windows
+
+package template
+`, 1)
+		content = strings.Replace(content, "package template_test\n", `// +build go1.13
+
+package template_test
+`, 1)
+
+		content = strings.Replace(content, "package parse\n", `// +build go1.13
+
+package parse
+`, 1)
+
+	}
+
+	return content
+
+}
+
+var goPackages = []goPackage{
+	goPackage{srcPkg: "text/template", dstPkg: "texttemplate",
+		replacer: func(name, content string) string { return textTemplateReplacers.Replace(commonReplace(name, content)) }},
+	goPackage{srcPkg: "html/template", dstPkg: "htmltemplate", replacer: func(name, content string) string {
+		if strings.HasSuffix(name, "content.go") {
+			// Remove template.HTML types. We need to use the Go types.
+			content = removeAll(`(?s)// Strings of content.*?\)\n`, content)
+		}
+
+		content = commonReplace(name, content)
+
+		return htmlTemplateReplacers.Replace(content)
+	},
+		rewriter: func(name string) {
+			for _, s := range []string{"CSS", "HTML", "HTMLAttr", "JS", "JSStr", "URL", "Srcset"} {
+				rewrite(name, fmt.Sprintf("%s -> htmltemplate.%s", s, s))
+			}
+			rewrite(name, `"text/template/parse" -> "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"`)
+		}},
+	goPackage{srcPkg: "internal/fmtsort", dstPkg: "fmtsort", rewriter: func(name string) {
+		rewrite(name, `"internal/fmtsort" -> "github.com/gohugoio/hugo/tpl/internal/go_templates/fmtsort"`)
+	}},
+}
+
+var fs = afero.NewOsFs()
+
+// Removes all non-Hugo files in the go_templates folder.
+func cleanFork() {
+	must(filepath.Walk(filepath.Join(forkRoot), func(path string, info os.FileInfo, err error) error {
+		if !info.IsDir() && len(path) > 10 && !strings.Contains(path, "hugo") {
+			must(fs.Remove(path))
+		}
+		return nil
+	}))
+}
+
+func must(err error, what ...string) {
+	if err != nil {
+		log.Fatal(what, " ERROR: ", err)
+	}
+}
+
+func copyGoPackage(dst, src string) {
+	from := filepath.Join(goSource, src)
+	to := filepath.Join(forkRoot, dst)
+	fmt.Println("Copy", from, "to", to)
+	must(hugio.CopyDir(fs, from, to, func(s string) bool { return true }))
+}
+
+func doWithGoFiles(dir string,
+	rewrite func(name string),
+	transform func(name, in string) string) {
+	if rewrite == nil && transform == nil {
+		return
+	}
+	must(filepath.Walk(filepath.Join(forkRoot, dir), func(path string, info os.FileInfo, err error) error {
+		if info.IsDir() {
+			return nil
+		}
+
+		if !strings.HasSuffix(path, ".go") || strings.Contains(path, "hugo_") {
+			return nil
+		}
+
+		fmt.Println("Handle", path)
+
+		if rewrite != nil {
+			rewrite(path)
+		}
+
+		if transform == nil {
+			return nil
+		}
+
+		data, err := ioutil.ReadFile(path)
+		must(err)
+		f, err := os.Create(path)
+		must(err)
+		defer f.Close()
+		_, err = f.WriteString(transform(path, string(data)))
+		must(err)
+
+		return nil
+	}))
+}
+
+func removeAll(expression, content string) string {
+	re := regexp.MustCompile(expression)
+	return re.ReplaceAllString(content, "")
+
+}
+
+func rewrite(filename, rule string) {
+	cmf := exec.Command("gofmt", "-w", "-r", rule, filename)
+	out, err := cmf.CombinedOutput()
+	if err != nil {
+		log.Fatal("gofmt failed:", string(out))
+	}
+}
+
+func goimports(dir string) {
+	cmf := exec.Command("goimports", "-w", dir)
+	out, err := cmf.CombinedOutput()
+	if err != nil {
+		log.Fatal("goimports failed:", string(out))
+	}
+}
+
+func gofmt(dir string) {
+	cmf := exec.Command("gofmt", "-w", dir)
+	out, err := cmf.CombinedOutput()
+	if err != nil {
+		log.Fatal("gofmt failed:", string(out))
+	}
+}