fix: render link in heading correctly in TOC (#6853)

- When you use a link in a heading such as `# [Text](link)` (instead of the conventional `# Text`) the TOC should only show `Text` and not `[Text](link)`.
- Use the `mdutil.Text` to only get the text from actual text nodes and not the text that was provided in the markdown input.
- Regression of e2fddcf681
- Resolves forgejo/forgejo#6847
- Added integration test.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/6853
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

modules/markup/markdown/transform_heading.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 
 	"code.gitea.io/gitea/modules/markup"
+	mdutil "code.gitea.io/gitea/modules/markup/markdown/util"
 	"code.gitea.io/gitea/modules/util"
 
 	"github.com/yuin/goldmark/ast"
@@ -19,7 +20,7 @@ func (g *ASTTransformer) transformHeading(_ *markup.RenderContext, v *ast.Headin
 			v.SetAttribute(attr.Name, []byte(fmt.Sprintf("%v", attr.Value)))
 		}
 	}
-	txt := v.Lines().Value(reader.Source())
+	txt := mdutil.Text(v, reader.Source())
 	header := markup.Header{
 		Text:  util.UnsafeBytesToString(txt),
 		Level: v.Level,

tests/integration/repo_wiki_test.go

@@ -89,3 +89,27 @@ func TestWikiBranchNormalize(t *testing.T) {
 	assert.Equal(t, setting.Repository.DefaultBranch, repo.GetWikiBranchName())
 	assertNormalizeButton(false)
 }
+
+func TestWikiTOC(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	username := "user2"
+	session := loginUser(t, username)
+
+	t.Run("Link in heading", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		req := NewRequestWithValues(t, "POST", "/user2/repo1/wiki/Home?action=_edit", map[string]string{
+			"_csrf":   GetCSRF(t, session, "/user2/repo1/wiki/Home"),
+			"title":   "Home",
+			"content": "# [Helpdesk](Helpdesk)",
+		})
+		session.MakeRequest(t, req, http.StatusSeeOther)
+
+		req = NewRequest(t, "GET", "/user2/repo1/wiki/Home")
+		resp := MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+
+		assert.EqualValues(t, "Helpdesk", htmlDoc.Find(".wiki-content-toc a").Text())
+	})
+}