Merge pull request '[PORT] gitea#30139: Refactor markdown render' (#3259) from algernon/forgejo:gitea/port/30139 into forgejo

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/3259
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>

modules/markup/markdown/goldmark.go

@@ -4,17 +4,12 @@
 package markdown
 
 import (
-	"bytes"
 	"fmt"
 	"regexp"
-	"slices"
 	"strings"
 
-	"code.gitea.io/gitea/modules/container"
 	"code.gitea.io/gitea/modules/markup"
-	"code.gitea.io/gitea/modules/markup/common"
 	"code.gitea.io/gitea/modules/setting"
-	giteautil "code.gitea.io/gitea/modules/util"
 
 	"github.com/yuin/goldmark/ast"
 	east "github.com/yuin/goldmark/extension/ast"
@@ -30,6 +25,12 @@ var byteMailto = []byte("mailto:")
 // ASTTransformer is a default transformer of the goldmark tree.
 type ASTTransformer struct{}
 
+func (g *ASTTransformer) applyElementDir(n ast.Node) {
+	if markup.DefaultProcessorHelper.ElementDir != "" {
+		n.SetAttributeString("dir", []byte(markup.DefaultProcessorHelper.ElementDir))
+	}
+}
+
 // Transform transforms the given AST tree.
 func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc parser.Context) {
 	firstChild := node.FirstChild()
@@ -46,12 +47,6 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 		tocMode = rc.TOC
 	}
 
-	applyElementDir := func(n ast.Node) {
-		if markup.DefaultProcessorHelper.ElementDir != "" {
-			n.SetAttributeString("dir", []byte(markup.DefaultProcessorHelper.ElementDir))
-		}
-	}
-
 	_ = ast.Walk(node, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
 		if !entering {
 			return ast.WalkContinue, nil
@@ -59,135 +54,15 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 
 		switch v := n.(type) {
 		case *ast.Heading:
-			for _, attr := range v.Attributes() {
-				if _, ok := attr.Value.([]byte); !ok {
-					v.SetAttribute(attr.Name, []byte(fmt.Sprintf("%v", attr.Value)))
-				}
-			}
-			txt := n.Text(reader.Source())
-			header := markup.Header{
-				Text:  util.BytesToReadOnlyString(txt),
-				Level: v.Level,
-			}
-			if id, found := v.AttributeString("id"); found {
-				header.ID = util.BytesToReadOnlyString(id.([]byte))
-			}
-			tocList = append(tocList, header)
-			applyElementDir(v)
+			g.transformHeading(ctx, v, reader, &tocList)
 		case *ast.Paragraph:
-			applyElementDir(v)
+			g.applyElementDir(v)
 		case *ast.Image:
-			// Images need two things:
-			//
-			// 1. Their src needs to munged to be a real value
-			// 2. If they're not wrapped with a link they need a link wrapper
-
-			// Check if the destination is a real link
-			if len(v.Destination) > 0 && !markup.IsLink(v.Destination) {
-				v.Destination = []byte(giteautil.URLJoin(
-					ctx.Links.ResolveMediaLink(ctx.IsWiki),
-					strings.TrimLeft(string(v.Destination), "/"),
-				))
-			}
-
-			parent := n.Parent()
-			// Create a link around image only if parent is not already a link
-			if _, ok := parent.(*ast.Link); !ok && parent != nil {
-				next := n.NextSibling()
-
-				// Create a link wrapper
-				wrap := ast.NewLink()
-				wrap.Destination = v.Destination
-				wrap.Title = v.Title
-				wrap.SetAttributeString("target", []byte("_blank"))
-
-				// Duplicate the current image node
-				image := ast.NewImage(ast.NewLink())
-				image.Destination = v.Destination
-				image.Title = v.Title
-				for _, attr := range v.Attributes() {
-					image.SetAttribute(attr.Name, attr.Value)
-				}
-				for child := v.FirstChild(); child != nil; {
-					next := child.NextSibling()
-					image.AppendChild(image, child)
-					child = next
-				}
-
-				// Append our duplicate image to the wrapper link
-				wrap.AppendChild(wrap, image)
-
-				// Wire in the next sibling
-				wrap.SetNextSibling(next)
-
-				// Replace the current node with the wrapper link
-				parent.ReplaceChild(parent, n, wrap)
-
-				// But most importantly ensure the next sibling is still on the old image too
-				v.SetNextSibling(next)
-			}
+			g.transformImage(ctx, v, reader)
 		case *ast.Link:
-			// Links need their href to munged to be a real value
-			link := v.Destination
-
-			// Do not process the link if it's not a link, starts with an hashtag
-			// (indicating it's an anchor link), starts with `mailto:` or any of the
-			// custom markdown URLs.
-			processLink := len(link) > 0 && !markup.IsLink(link) &&
-				link[0] != '#' && !bytes.HasPrefix(link, byteMailto) &&
-				!slices.ContainsFunc(setting.Markdown.CustomURLSchemes, func(s string) bool {
-					return bytes.HasPrefix(link, []byte(s+":"))
-				})
-
-			if processLink {
-				var base string
-				if ctx.IsWiki {
-					base = ctx.Links.WikiLink()
-				} else if ctx.Links.HasBranchInfo() {
-					base = ctx.Links.SrcLink()
-				} else {
-					base = ctx.Links.Base
-				}
-
-				link = []byte(giteautil.URLJoin(base, string(link)))
-			}
-			if len(link) > 0 && link[0] == '#' {
-				link = []byte("#user-content-" + string(link)[1:])
-			}
-			v.Destination = link
+			g.transformLink(ctx, v, reader)
 		case *ast.List:
-			if v.HasChildren() {
-				children := make([]ast.Node, 0, v.ChildCount())
-				child := v.FirstChild()
-				for child != nil {
-					children = append(children, child)
-					child = child.NextSibling()
-				}
-				v.RemoveChildren(v)
-
-				for _, child := range children {
-					listItem := child.(*ast.ListItem)
-					if !child.HasChildren() || !child.FirstChild().HasChildren() {
-						v.AppendChild(v, child)
-						continue
-					}
-					taskCheckBox, ok := child.FirstChild().FirstChild().(*east.TaskCheckBox)
-					if !ok {
-						v.AppendChild(v, child)
-						continue
-					}
-					newChild := NewTaskCheckBoxListItem(listItem)
-					newChild.IsChecked = taskCheckBox.IsChecked
-					newChild.SetAttributeString("class", []byte("task-list-item"))
-					segments := newChild.FirstChild().Lines()
-					if segments.Len() > 0 {
-						segment := segments.At(0)
-						newChild.SourcePosition = rc.metaLength + segment.Start
-					}
-					v.AppendChild(v, newChild)
-				}
-			}
-			applyElementDir(v)
+			g.transformList(ctx, v, reader, rc)
 		case *ast.Text:
 			if v.SoftLineBreak() && !v.HardLineBreak() {
 				if ctx.Metas["mode"] != "document" {
@@ -197,10 +72,7 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 				}
 			}
 		case *ast.CodeSpan:
-			colorContent := n.Text(reader.Source())
-			if matchColor(strings.ToLower(string(colorContent))) {
-				v.AppendChild(v, NewColorPreview(colorContent))
-			}
+			g.transformCodeSpan(ctx, v, reader)
 		}
 		return ast.WalkContinue, nil
 	})
@@ -222,50 +94,6 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 	}
 }
 
-type prefixedIDs struct {
-	values container.Set[string]
-}
-
-// Generate generates a new element id.
-func (p *prefixedIDs) Generate(value []byte, kind ast.NodeKind) []byte {
-	dft := []byte("id")
-	if kind == ast.KindHeading {
-		dft = []byte("heading")
-	}
-	return p.GenerateWithDefault(value, dft)
-}
-
-// Generate generates a new element id.
-func (p *prefixedIDs) GenerateWithDefault(value, dft []byte) []byte {
-	result := common.CleanValue(value)
-	if len(result) == 0 {
-		result = dft
-	}
-	if !bytes.HasPrefix(result, []byte("user-content-")) {
-		result = append([]byte("user-content-"), result...)
-	}
-	if p.values.Add(util.BytesToReadOnlyString(result)) {
-		return result
-	}
-	for i := 1; ; i++ {
-		newResult := fmt.Sprintf("%s-%d", result, i)
-		if p.values.Add(newResult) {
-			return []byte(newResult)
-		}
-	}
-}
-
-// Put puts a given element id to the used ids table.
-func (p *prefixedIDs) Put(value []byte) {
-	p.values.Add(util.BytesToReadOnlyString(value))
-}
-
-func newPrefixedIDs() *prefixedIDs {
-	return &prefixedIDs{
-		values: make(container.Set[string]),
-	}
-}
-
 // NewHTMLRenderer creates a HTMLRenderer to render
 // in the gitea form.
 func NewHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
@@ -295,38 +123,6 @@ func (r *HTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
 	reg.Register(east.KindTaskCheckBox, r.renderTaskCheckBox)
 }
 
-// renderCodeSpan renders CodeSpan elements (like goldmark upstream does) but also renders ColorPreview elements.
-// See #21474 for reference
-func (r *HTMLRenderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
-	if entering {
-		if n.Attributes() != nil {
-			_, _ = w.WriteString("<code")
-			html.RenderAttributes(w, n, html.CodeAttributeFilter)
-			_ = w.WriteByte('>')
-		} else {
-			_, _ = w.WriteString("<code>")
-		}
-		for c := n.FirstChild(); c != nil; c = c.NextSibling() {
-			switch v := c.(type) {
-			case *ast.Text:
-				segment := v.Segment
-				value := segment.Value(source)
-				if bytes.HasSuffix(value, []byte("\n")) {
-					r.Writer.RawWrite(w, value[:len(value)-1])
-					r.Writer.RawWrite(w, []byte(" "))
-				} else {
-					r.Writer.RawWrite(w, value)
-				}
-			case *ColorPreview:
-				_, _ = w.WriteString(fmt.Sprintf(`<span class="color-preview" style="background-color: %v"></span>`, string(v.Color)))
-			}
-		}
-		return ast.WalkSkipChildren, nil
-	}
-	_, _ = w.WriteString("</code>")
-	return ast.WalkContinue, nil
-}
-
 func (r *HTMLRenderer) renderDocument(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Document)
 
@@ -415,38 +211,3 @@ func (r *HTMLRenderer) renderIcon(w util.BufWriter, source []byte, node ast.Node
 
 	return ast.WalkContinue, nil
 }
-
-func (r *HTMLRenderer) renderTaskCheckBoxListItem(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
-	n := node.(*TaskCheckBoxListItem)
-	if entering {
-		if n.Attributes() != nil {
-			_, _ = w.WriteString("<li")
-			html.RenderAttributes(w, n, html.ListItemAttributeFilter)
-			_ = w.WriteByte('>')
-		} else {
-			_, _ = w.WriteString("<li>")
-		}
-		fmt.Fprintf(w, `<input type="checkbox" disabled="" data-source-position="%d"`, n.SourcePosition)
-		if n.IsChecked {
-			_, _ = w.WriteString(` checked=""`)
-		}
-		if r.XHTML {
-			_, _ = w.WriteString(` />`)
-		} else {
-			_ = w.WriteByte('>')
-		}
-		fc := n.FirstChild()
-		if fc != nil {
-			if _, ok := fc.(*ast.TextBlock); !ok {
-				_ = w.WriteByte('\n')
-			}
-		}
-	} else {
-		_, _ = w.WriteString("</li>\n")
-	}
-	return ast.WalkContinue, nil
-}
-
-func (r *HTMLRenderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
-	return ast.WalkContinue, nil
-}

modules/markup/markdown/prefixed_id.go

@@ -0,0 +1,59 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"bytes"
+	"fmt"
+
+	"code.gitea.io/gitea/modules/container"
+	"code.gitea.io/gitea/modules/markup/common"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/util"
+)
+
+type prefixedIDs struct {
+	values container.Set[string]
+}
+
+// Generate generates a new element id.
+func (p *prefixedIDs) Generate(value []byte, kind ast.NodeKind) []byte {
+	dft := []byte("id")
+	if kind == ast.KindHeading {
+		dft = []byte("heading")
+	}
+	return p.GenerateWithDefault(value, dft)
+}
+
+// GenerateWithDefault generates a new element id.
+func (p *prefixedIDs) GenerateWithDefault(value, dft []byte) []byte {
+	result := common.CleanValue(value)
+	if len(result) == 0 {
+		result = dft
+	}
+	if !bytes.HasPrefix(result, []byte("user-content-")) {
+		result = append([]byte("user-content-"), result...)
+	}
+	if p.values.Add(util.BytesToReadOnlyString(result)) {
+		return result
+	}
+	for i := 1; ; i++ {
+		newResult := fmt.Sprintf("%s-%d", result, i)
+		if p.values.Add(newResult) {
+			return []byte(newResult)
+		}
+	}
+}
+
+// Put puts a given element id to the used ids table.
+func (p *prefixedIDs) Put(value []byte) {
+	p.values.Add(util.BytesToReadOnlyString(value))
+}
+
+func newPrefixedIDs() *prefixedIDs {
+	return &prefixedIDs{
+		values: make(container.Set[string]),
+	}
+}

modules/markup/markdown/transform_codespan.go

@@ -0,0 +1,56 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/modules/markup"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+// renderCodeSpan renders CodeSpan elements (like goldmark upstream does) but also renders ColorPreview elements.
+// See #21474 for reference
+func (r *HTMLRenderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		if n.Attributes() != nil {
+			_, _ = w.WriteString("<code")
+			html.RenderAttributes(w, n, html.CodeAttributeFilter)
+			_ = w.WriteByte('>')
+		} else {
+			_, _ = w.WriteString("<code>")
+		}
+		for c := n.FirstChild(); c != nil; c = c.NextSibling() {
+			switch v := c.(type) {
+			case *ast.Text:
+				segment := v.Segment
+				value := segment.Value(source)
+				if bytes.HasSuffix(value, []byte("\n")) {
+					r.Writer.RawWrite(w, value[:len(value)-1])
+					r.Writer.RawWrite(w, []byte(" "))
+				} else {
+					r.Writer.RawWrite(w, value)
+				}
+			case *ColorPreview:
+				_, _ = w.WriteString(fmt.Sprintf(`<span class="color-preview" style="background-color: %v"></span>`, string(v.Color)))
+			}
+		}
+		return ast.WalkSkipChildren, nil
+	}
+	_, _ = w.WriteString("</code>")
+	return ast.WalkContinue, nil
+}
+
+func (g *ASTTransformer) transformCodeSpan(ctx *markup.RenderContext, v *ast.CodeSpan, reader text.Reader) {
+	colorContent := v.Text(reader.Source())
+	if matchColor(strings.ToLower(string(colorContent))) {
+		v.AppendChild(v, NewColorPreview(colorContent))
+	}
+}

modules/markup/markdown/transform_heading.go

@@ -0,0 +1,32 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/modules/markup"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+func (g *ASTTransformer) transformHeading(ctx *markup.RenderContext, v *ast.Heading, reader text.Reader, tocList *[]markup.Header) {
+	for _, attr := range v.Attributes() {
+		if _, ok := attr.Value.([]byte); !ok {
+			v.SetAttribute(attr.Name, []byte(fmt.Sprintf("%v", attr.Value)))
+		}
+	}
+	txt := v.Text(reader.Source())
+	header := markup.Header{
+		Text:  util.BytesToReadOnlyString(txt),
+		Level: v.Level,
+	}
+	if id, found := v.AttributeString("id"); found {
+		header.ID = util.BytesToReadOnlyString(id.([]byte))
+	}
+	*tocList = append(*tocList, header)
+	g.applyElementDir(v)
+}

modules/markup/markdown/transform_image.go

@@ -0,0 +1,66 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"strings"
+
+	"code.gitea.io/gitea/modules/markup"
+	giteautil "code.gitea.io/gitea/modules/util"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
+)
+
+func (g *ASTTransformer) transformImage(ctx *markup.RenderContext, v *ast.Image, reader text.Reader) {
+	// Images need two things:
+	//
+	// 1. Their src needs to munged to be a real value
+	// 2. If they're not wrapped with a link they need a link wrapper
+
+	// Check if the destination is a real link
+	if len(v.Destination) > 0 && !markup.IsLink(v.Destination) {
+		v.Destination = []byte(giteautil.URLJoin(
+			ctx.Links.ResolveMediaLink(ctx.IsWiki),
+			strings.TrimLeft(string(v.Destination), "/"),
+		))
+	}
+
+	parent := v.Parent()
+	// Create a link around image only if parent is not already a link
+	if _, ok := parent.(*ast.Link); !ok && parent != nil {
+		next := v.NextSibling()
+
+		// Create a link wrapper
+		wrap := ast.NewLink()
+		wrap.Destination = v.Destination
+		wrap.Title = v.Title
+		wrap.SetAttributeString("target", []byte("_blank"))
+
+		// Duplicate the current image node
+		image := ast.NewImage(ast.NewLink())
+		image.Destination = v.Destination
+		image.Title = v.Title
+		for _, attr := range v.Attributes() {
+			image.SetAttribute(attr.Name, attr.Value)
+		}
+		for child := v.FirstChild(); child != nil; {
+			next := child.NextSibling()
+			image.AppendChild(image, child)
+			child = next
+		}
+
+		// Append our duplicate image to the wrapper link
+		wrap.AppendChild(wrap, image)
+
+		// Wire in the next sibling
+		wrap.SetNextSibling(next)
+
+		// Replace the current node with the wrapper link
+		parent.ReplaceChild(parent, v, wrap)
+
+		// But most importantly ensure the next sibling is still on the old image too
+		v.SetNextSibling(next)
+	}
+}

modules/markup/markdown/transform_link.go

@@ -0,0 +1,47 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"bytes"
+	"slices"
+
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/setting"
+	giteautil "code.gitea.io/gitea/modules/util"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
+)
+
+func (g *ASTTransformer) transformLink(ctx *markup.RenderContext, v *ast.Link, reader text.Reader) {
+	// Links need their href to munged to be a real value
+	link := v.Destination
+
+	// Do not process the link if it's not a link, starts with an hashtag
+	// (indicating it's an anchor link), starts with `mailto:` or any of the
+	// custom markdown URLs.
+	processLink := len(link) > 0 && !markup.IsLink(link) &&
+		link[0] != '#' && !bytes.HasPrefix(link, byteMailto) &&
+		!slices.ContainsFunc(setting.Markdown.CustomURLSchemes, func(s string) bool {
+			return bytes.HasPrefix(link, []byte(s+":"))
+		})
+
+	if processLink {
+		var base string
+		if ctx.IsWiki {
+			base = ctx.Links.WikiLink()
+		} else if ctx.Links.HasBranchInfo() {
+			base = ctx.Links.SrcLink()
+		} else {
+			base = ctx.Links.Base
+		}
+
+		link = []byte(giteautil.URLJoin(base, string(link)))
+	}
+	if len(link) > 0 && link[0] == '#' {
+		link = []byte("#user-content-" + string(link)[1:])
+	}
+	v.Destination = link
+}

modules/markup/markdown/transform_list.go

@@ -0,0 +1,86 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/modules/markup"
+
+	"github.com/yuin/goldmark/ast"
+	east "github.com/yuin/goldmark/extension/ast"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+func (r *HTMLRenderer) renderTaskCheckBoxListItem(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*TaskCheckBoxListItem)
+	if entering {
+		if n.Attributes() != nil {
+			_, _ = w.WriteString("<li")
+			html.RenderAttributes(w, n, html.ListItemAttributeFilter)
+			_ = w.WriteByte('>')
+		} else {
+			_, _ = w.WriteString("<li>")
+		}
+		fmt.Fprintf(w, `<input type="checkbox" disabled="" data-source-position="%d"`, n.SourcePosition)
+		if n.IsChecked {
+			_, _ = w.WriteString(` checked=""`)
+		}
+		if r.XHTML {
+			_, _ = w.WriteString(` />`)
+		} else {
+			_ = w.WriteByte('>')
+		}
+		fc := n.FirstChild()
+		if fc != nil {
+			if _, ok := fc.(*ast.TextBlock); !ok {
+				_ = w.WriteByte('\n')
+			}
+		}
+	} else {
+		_, _ = w.WriteString("</li>\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *HTMLRenderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	return ast.WalkContinue, nil
+}
+
+func (g *ASTTransformer) transformList(ctx *markup.RenderContext, v *ast.List, reader text.Reader, rc *RenderConfig) {
+	if v.HasChildren() {
+		children := make([]ast.Node, 0, v.ChildCount())
+		child := v.FirstChild()
+		for child != nil {
+			children = append(children, child)
+			child = child.NextSibling()
+		}
+		v.RemoveChildren(v)
+
+		for _, child := range children {
+			listItem := child.(*ast.ListItem)
+			if !child.HasChildren() || !child.FirstChild().HasChildren() {
+				v.AppendChild(v, child)
+				continue
+			}
+			taskCheckBox, ok := child.FirstChild().FirstChild().(*east.TaskCheckBox)
+			if !ok {
+				v.AppendChild(v, child)
+				continue
+			}
+			newChild := NewTaskCheckBoxListItem(listItem)
+			newChild.IsChecked = taskCheckBox.IsChecked
+			newChild.SetAttributeString("class", []byte("task-list-item"))
+			segments := newChild.FirstChild().Lines()
+			if segments.Len() > 0 {
+				segment := segments.At(0)
+				newChild.SourcePosition = rc.metaLength + segment.Start
+			}
+			v.AppendChild(v, newChild)
+		}
+	}
+	g.applyElementDir(v)
+}