Revert "markup/tableofcontents: Skip empty TOC levels"

This reverts commit 7d4af7a179.

Closes #14898

markup/goldmark/toc_integration_test.go

@@ -305,101 +305,6 @@ title: home
 	b.AssertFileExists("public/index.html", true)
 }
 
-func TestTableOfContentsSkippedHeadingLevelsIssue7128(t *testing.T) {
-	t.Parallel()
-
-	filesTemplate := `
--- hugo.toml --
-disableKinds = ['home','rss','section','sitemap','taxonomy','term']
-TOC_CONFIG
--- layouts/page.html --
-{{ .TableOfContents }}
--- content/p1.md --
----
-title: p1
----
-## Extra-Curriculars
-
-#### Heading Four Here without Heading Three Before It
-
-## Technology
-
-#### Heading Four Here without Heading Three Before It
-`
-
-	t.Run("default end level", func(t *testing.T) {
-		t.Parallel()
-
-		files := strings.ReplaceAll(filesTemplate, "TOC_CONFIG", "")
-		b := hugolib.Test(t, files)
-
-		b.AssertFileContentExact("public/p1/index.html", `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#extra-curriculars">Extra-Curriculars</a></li>
-    <li><a href="#technology">Technology</a></li>
-  </ul>
-</nav>`)
-	})
-
-	t.Run("include skipped level", func(t *testing.T) {
-		t.Parallel()
-
-		files := strings.ReplaceAll(filesTemplate, "TOC_CONFIG", `
-[markup.tableOfContents]
-startLevel = 2
-endLevel = -1`)
-		b := hugolib.Test(t, files)
-
-		b.AssertFileContentExact("public/p1/index.html", `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#extra-curriculars">Extra-Curriculars</a>
-      <ul>
-        <li><a href="#heading-four-here-without-heading-three-before-it">Heading Four Here without Heading Three Before It</a></li>
-      </ul>
-    </li>
-    <li><a href="#technology">Technology</a>
-      <ul>
-        <li><a href="#heading-four-here-without-heading-three-before-it-1">Heading Four Here without Heading Three Before It</a></li>
-      </ul>
-    </li>
-  </ul>
-</nav>`)
-	})
-
-	t.Run("starts at h4", func(t *testing.T) {
-		t.Parallel()
-
-		files := `
--- hugo.toml --
-disableKinds = ['home','rss','section','sitemap','taxonomy','term']
-[markup.tableOfContents]
-startLevel = 2
-endLevel = -1
--- layouts/page.html --
-{{ .TableOfContents }}
--- content/p1.md --
----
-title: p1
----
-#### Heading Four First
-
-###### Heading Six After Heading Four
-`
-
-		b := hugolib.Test(t, files)
-
-		b.AssertFileContentExact("public/p1/index.html", `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#heading-four-first">Heading Four First</a>
-      <ul>
-        <li><a href="#heading-six-after-heading-four">Heading Six After Heading Four</a></li>
-      </ul>
-    </li>
-  </ul>
-</nav>`)
-	})
-}
-
 // Issue 12605
 func TestTableOfContentsWithGoldmarkExtras(t *testing.T) {
 	t.Parallel()

markup/tableofcontents/tableofcontents.go

@@ -195,13 +195,23 @@ func (b *tocBuilder) Build() {
 
 func (b *tocBuilder) writeNav(h Headings) {
 	b.s.WriteString("<nav id=\"TableOfContents\">")
-	b.writeHeadings(1, 0, h)
+	b.writeHeadings(1, 0, b.h)
 	b.s.WriteString("</nav>")
 }
 
 func (b *tocBuilder) writeHeadings(level, indent int, h Headings) {
-	headings := b.collectHeadings(level, h)
-	hasChildren := len(headings) > 0
+	if level < b.startLevel {
+		for _, h := range h {
+			b.writeHeadings(level+1, indent, h.Headings)
+		}
+		return
+	}
+
+	if b.stopLevel != -1 && level > b.stopLevel {
+		return
+	}
+
+	hasChildren := len(h) > 0
 
 	if hasChildren {
 		b.s.WriteString("\n")
@@ -213,8 +223,8 @@ func (b *tocBuilder) writeHeadings(level, indent int, h Headings) {
 		}
 	}
 
-	for _, h := range headings {
-		b.writeHeading(h.level, indent+2, h.h)
+	for _, h := range h {
+		b.writeHeading(level+1, indent+2, h)
 	}
 
 	if hasChildren {
@@ -229,35 +239,13 @@ func (b *tocBuilder) writeHeadings(level, indent int, h Headings) {
 	}
 }
 
-type tocHeading struct {
-	h     *Heading
-	level int
-}
-
-func (b *tocBuilder) collectHeadings(level int, h Headings) []tocHeading {
-	var out []tocHeading
-
-	for _, h := range h {
-		if h.IsZero() || level < b.startLevel {
-			out = append(out, b.collectHeadings(level+1, h.Headings)...)
-			continue
-		}
-
-		if b.stopLevel != -1 && level > b.stopLevel {
-			continue
-		}
-
-		out = append(out, tocHeading{h: h, level: level})
-	}
-
-	return out
-}
-
 func (b *tocBuilder) writeHeading(level, indent int, h *Heading) {
 	b.indent(indent)
 	b.s.WriteString("<li>")
-	b.s.WriteString("<a href=\"#" + h.ID + "\">" + h.Title + "</a>")
-	b.writeHeadings(level+1, indent, h.Headings)
+	if !h.IsZero() {
+		b.s.WriteString("<a href=\"#" + h.ID + "\">" + h.Title + "</a>")
+	}
+	b.writeHeadings(level, indent, h.Headings)
 	b.s.WriteString("</li>\n")
 }
 

markup/tableofcontents/tableofcontents_test.go

@@ -14,7 +14,6 @@
 package tableofcontents
 
 import (
-	"strings"
 	"testing"
 
 	qt "github.com/frankban/quicktest"
@@ -128,9 +127,21 @@ func TestTocMissingParent(t *testing.T) {
 	got := string(tocHTML)
 	c.Assert(got, qt.Equals, `<nav id="TableOfContents">
   <ul>
-    <li><a href="#h2">H2</a></li>
-    <li><a href="#h3">H3</a></li>
-    <li><a href="#h3">H3</a></li>
+    <li>
+      <ul>
+        <li><a href="#h2">H2</a></li>
+      </ul>
+    </li>
+    <li>
+      <ul>
+        <li>
+          <ul>
+            <li><a href="#h3">H3</a></li>
+            <li><a href="#h3">H3</a></li>
+          </ul>
+        </li>
+      </ul>
+    </li>
   </ul>
 </nav>`, qt.Commentf(got))
 
@@ -147,159 +158,25 @@ func TestTocMissingParent(t *testing.T) {
 	got = string(tocHTML)
 	c.Assert(got, qt.Equals, `<nav id="TableOfContents">
   <ol>
-    <li><a href="#h2">H2</a></li>
-    <li><a href="#h3">H3</a></li>
-    <li><a href="#h3">H3</a></li>
+    <li>
+      <ol>
+        <li><a href="#h2">H2</a></li>
+      </ol>
+    </li>
+    <li>
+      <ol>
+        <li>
+          <ol>
+            <li><a href="#h3">H3</a></li>
+            <li><a href="#h3">H3</a></li>
+          </ol>
+        </li>
+      </ol>
+    </li>
   </ol>
 </nav>`, qt.Commentf(got))
 }
 
-func TestTocMissingIntermediateLevels(t *testing.T) {
-	c := qt.New(t)
-
-	type item struct {
-		title string
-		id    string
-		row   int
-		level int
-	}
-
-	for _, test := range []struct {
-		name     string
-		items    []item
-		expected string
-	}{
-		{
-			name: "h2 to h4",
-			items: []item{
-				{title: "H2", id: "h2", level: 1},
-				{title: "H4", id: "h4", level: 3},
-			},
-			expected: `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h2">H2</a>
-      <ul>
-        <li><a href="#h4">H4</a></li>
-      </ul>
-    </li>
-  </ul>
-</nav>`,
-		},
-		{
-			name: "h2 to h5",
-			items: []item{
-				{title: "H2", id: "h2", level: 1},
-				{title: "H5", id: "h5", level: 4},
-			},
-			expected: `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h2">H2</a>
-      <ul>
-        <li><a href="#h5">H5</a></li>
-      </ul>
-    </li>
-  </ul>
-</nav>`,
-		},
-		{
-			name: "h2 to h6",
-			items: []item{
-				{title: "H2", id: "h2", level: 1},
-				{title: "H6", id: "h6", level: 5},
-			},
-			expected: `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h2">H2</a>
-      <ul>
-        <li><a href="#h6">H6</a></li>
-      </ul>
-    </li>
-  </ul>
-</nav>`,
-		},
-		{
-			name: "h3 to h5",
-			items: []item{
-				{title: "H3", id: "h3", level: 2},
-				{title: "H5", id: "h5", level: 4},
-			},
-			expected: `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h3">H3</a>
-      <ul>
-        <li><a href="#h5">H5</a></li>
-      </ul>
-    </li>
-  </ul>
-</nav>`,
-		},
-		{
-			name: "starts at h4",
-			items: []item{
-				{title: "H4", id: "h4", level: 3},
-			},
-			expected: `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h4">H4</a></li>
-  </ul>
-</nav>`,
-		},
-		{
-			name: "starts at h6",
-			items: []item{
-				{title: "H6", id: "h6", level: 5},
-			},
-			expected: `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h6">H6</a></li>
-  </ul>
-</nav>`,
-		},
-	} {
-		c.Run(test.name, func(c *qt.C) {
-			toc := &Fragments{}
-			for _, item := range test.items {
-				toc.addAt(&Heading{Title: item.title, ID: item.id}, item.row, item.level)
-			}
-
-			tocHTML, err := toc.ToHTML(2, -1, false)
-			c.Assert(err, qt.IsNil)
-			got := string(tocHTML)
-			c.Assert(got, qt.Equals, test.expected, qt.Commentf(got))
-			c.Assert(got, qt.Not(qt.Contains), "<li>\n")
-			c.Assert(hasListItemWithoutAnchor(got), qt.Equals, false)
-		})
-	}
-
-	toc := &Fragments{}
-	toc.addAt(&Heading{Title: "H2", ID: "h2"}, 0, 1)
-	toc.addAt(&Heading{Title: "H4", ID: "h4"}, 0, 3)
-
-	tocHTML, err := toc.ToHTML(2, 3, false)
-	c.Assert(err, qt.IsNil)
-	got := string(tocHTML)
-	c.Assert(got, qt.Equals, `<nav id="TableOfContents">
-  <ul>
-    <li><a href="#h2">H2</a></li>
-  </ul>
-</nav>`, qt.Commentf(got))
-	c.Assert(got, qt.Not(qt.Contains), "<li>\n")
-	c.Assert(hasListItemWithoutAnchor(got), qt.Equals, false)
-}
-
-func hasListItemWithoutAnchor(s string) bool {
-	for {
-		i := strings.Index(s, "<li>")
-		if i == -1 {
-			return false
-		}
-		s = s[i+len("<li>"):]
-		if !strings.HasPrefix(strings.TrimLeft(s, " \n\t\r"), "<a ") {
-			return true
-		}
-	}
-}
-
 func TestTocMisc(t *testing.T) {
 	c := qt.New(t)