fix: prevent HTML4 doctypes from causing generation errors

a-h · a-h · commit 09e79ccc3186 · 2025-03-12T23:31:06.000Z
diff --git a/.version b/.version
@@ -1 +1 @@
-0.3.836
+0.3.840
diff --git a/generator/generator.go b/generator/generator.go
@@ -671,12 +671,17 @@ func (g *generator) writeWhitespaceTrailer(indentLevel int, n parser.TrailingSpa
 }
 
 func (g *generator) writeDocType(indentLevel int, n parser.DocType) (err error) {
-	if _, err = g.w.WriteStringLiteral(indentLevel, fmt.Sprintf("<!doctype %s>", n.Value)); err != nil {
+	if _, err = g.w.WriteStringLiteral(indentLevel, fmt.Sprintf("<!doctype %s>", escapeQuotes(n.Value))); err != nil {
 		return err
 	}
 	return nil
 }
 
+func escapeQuotes(s string) string {
+	quoted := strconv.Quote(s)
+	return quoted[1 : len(quoted)-1]
+}
+
 func (g *generator) writeIfExpression(indentLevel int, n parser.IfExpression, nextNode parser.Node) (err error) {
 	var r parser.Range
 	// if
@@ -1129,8 +1134,7 @@ func (g *generator) writeBoolConstantAttribute(indentLevel int, attr parser.Bool
 func (g *generator) writeConstantAttribute(indentLevel int, attr parser.ConstantAttribute) (err error) {
 	name := html.EscapeString(attr.Name)
 	value := html.EscapeString(attr.Value)
-	value = strconv.Quote(value)
-	value = value[1 : len(value)-1]
+	value = escapeQuotes(value)
 	if _, err = g.w.WriteStringLiteral(indentLevel, fmt.Sprintf(` %s=\"%s\"`, name, value)); err != nil {
 		return err
 	}
@@ -1515,8 +1519,7 @@ func (g *generator) writeWhitespace(indentLevel int, n parser.Whitespace) (err e
 }
 
 func (g *generator) writeText(indentLevel int, n parser.Text) (err error) {
-	quoted := strconv.Quote(n.Value)
-	_, err = g.w.WriteStringLiteral(indentLevel, quoted[1:len(quoted)-1])
+	_, err = g.w.WriteStringLiteral(indentLevel, escapeQuotes(n.Value))
 	return err
 }
 
diff --git a/generator/test-doctype-html4/expected.html b/generator/test-doctype-html4/expected.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>title</title>
+  </head>
+  <body>content</body>
+</html>
diff --git a/generator/test-doctype-html4/render_test.go b/generator/test-doctype-html4/render_test.go
@@ -0,0 +1,23 @@
+package testdoctype
+
+import (
+	_ "embed"
+	"testing"
+
+	"github.com/a-h/templ/generator/htmldiff"
+)
+
+//go:embed expected.html
+var expected string
+
+func Test(t *testing.T) {
+	component := Layout("title", "content")
+
+	diff, err := htmldiff.Diff(component, expected)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if diff != "" {
+		t.Error(diff)
+	}
+}
diff --git a/generator/test-doctype-html4/template.templ b/generator/test-doctype-html4/template.templ
@@ -0,0 +1,14 @@
+package testdoctype
+
+templ Layout(title, content string) {
+	<!DOCTYPE HTML PUBLIC "http://www.w3.org/TR/html4/loose.dtd">
+	<html lang="en">
+		<head>
+			<meta charset="UTF-8"/>
+			<meta http-equiv="X-UA-Compatible" content="IE=edge"/>
+			<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
+			<title>{ title }</title>
+		</head>
+		<body>{ content }</body>
+	</html>
+}
diff --git a/generator/test-doctype-html4/template_templ.go b/generator/test-doctype-html4/template_templ.go

Original file line number	Diff line number	Diff line change
`@@ -671,12 +671,17 @@ func (g *generator) writeWhitespaceTrailer(indentLevel int, n parser.TrailingSpa`
`671`	`671`	`}`
`672`	`672`
`673`	`673`	`func (g *generator) writeDocType(indentLevel int, n parser.DocType) (err error) {`
`674`		`- if _, err = g.w.WriteStringLiteral(indentLevel, fmt.Sprintf("<!doctype %s>", n.Value)); err != nil {`
	`674`	`+ if _, err = g.w.WriteStringLiteral(indentLevel, fmt.Sprintf("<!doctype %s>", escapeQuotes(n.Value))); err != nil {`
`675`	`675`	`return err`
`676`	`676`	`}`
`677`	`677`	`return nil`
`678`	`678`	`}`
`679`	`679`
	`680`	`+func escapeQuotes(s string) string {`
	`681`	`+ quoted := strconv.Quote(s)`
	`682`	`+ return quoted[1 : len(quoted)-1]`
	`683`	`+}`
	`684`	`+`
`680`	`685`	`func (g *generator) writeIfExpression(indentLevel int, n parser.IfExpression, nextNode parser.Node) (err error) {`
`681`	`686`	`var r parser.Range`
`682`	`687`	`// if`
`@@ -1129,8 +1134,7 @@ func (g *generator) writeBoolConstantAttribute(indentLevel int, attr parser.Bool`
`1129`	`1134`	`func (g *generator) writeConstantAttribute(indentLevel int, attr parser.ConstantAttribute) (err error) {`
`1130`	`1135`	`name := html.EscapeString(attr.Name)`
`1131`	`1136`	`value := html.EscapeString(attr.Value)`
`1132`		`- value = strconv.Quote(value)`
`1133`		`- value = value[1 : len(value)-1]`
	`1137`	`+ value = escapeQuotes(value)`
`1134`	`1138`	if _, err = g.w.WriteStringLiteral(indentLevel, fmt.Sprintf(` %s=\"%s\"`, name, value)); err != nil {
`1135`	`1139`	`return err`
`1136`	`1140`	`}`
`@@ -1515,8 +1519,7 @@ func (g *generator) writeWhitespace(indentLevel int, n parser.Whitespace) (err e`
`1515`	`1519`	`}`
`1516`	`1520`
`1517`	`1521`	`func (g *generator) writeText(indentLevel int, n parser.Text) (err error) {`
`1518`		`- quoted := strconv.Quote(n.Value)`
`1519`		`- _, err = g.w.WriteStringLiteral(indentLevel, quoted[1:len(quoted)-1])`
	`1522`	`+ _, err = g.w.WriteStringLiteral(indentLevel, escapeQuotes(n.Value))`
`1520`	`1523`	`return err`
`1521`	`1524`	`}`
`1522`	`1525`