Fix footnote jump behavior on the issue page.

modules/markup/html.go

@@ -320,6 +320,8 @@ func visitNode(ctx *RenderContext, procs []processor, node *html.Node) *html.Nod
 	}
 
 	processNodeAttrID(node)
+	processFootnoteID(ctx, node)
+	processFootnoteBackHref(ctx, node)
 
 	if isEmojiNode(node) {
 		// TextNode emoji will be converted to `<span class="emoji">`, then the next iteration will visit the "span"

modules/markup/html_issue_test.go

@@ -30,6 +30,7 @@ func TestRender_IssueList(t *testing.T) {
 		rctx := markup.NewTestRenderContext(markup.TestAppURL, map[string]string{
 			"user": "test-user", "repo": "test-repo",
 			"markupAllowShortIssuePattern": "true",
+			"issue_comment_id":             "12345",
 		})
 		out, err := markdown.RenderString(rctx, input)
 		require.NoError(t, err)
@@ -69,4 +70,22 @@ func TestRender_IssueList(t *testing.T) {
 </ul>`,
 		)
 	})
+
+	t.Run("IssueFootnote", func(t *testing.T) {
+		test(
+			"foo[^1][^2]\n\n[^1]: bar\n[^2]: baz",
+			`<p>foo<sup id="fnref:user-content-1-12345"><a href="#fn:user-content-1-12345" rel="nofollow">1</a></sup><sup id="fnref:user-content-2-12345"><a href="#fn:user-content-2-12345" rel="nofollow">2</a></sup></p>
+<div>
+<hr/>
+<ol>
+<li id="fn:user-content-1-12345">
+<p>bar <a href="#fnref:user-content-1-12345" rel="nofollow">↩︎</a></p>
+</li>
+<li id="fn:user-content-2-12345">
+<p>baz <a href="#fnref:user-content-2-12345" rel="nofollow">↩︎</a></p>
+</li>
+</ol>
+</div>`,
+		)
+	})
 }

modules/markup/html_node.go

@@ -15,6 +15,14 @@ func isAnchorIDUserContent(s string) bool {
 	return strings.HasPrefix(s, "user-content-") || strings.Contains(s, ":user-content-")
 }
 
+func isAnchorIDFootnote(s string) bool {
+	return strings.HasPrefix(s, "fnref:user-content-") || strings.HasPrefix(s, "fn:user-content-")
+}
+
+func isAnchorHrefFootnote(s string) bool {
+	return strings.HasPrefix(s, "#fnref:user-content-") || strings.HasPrefix(s, "#fn:user-content-")
+}
+
 func processNodeAttrID(node *html.Node) {
 	// Add user-content- to IDs and "#" links if they don't already have them,
 	// and convert the link href to a relative link to the host root
@@ -27,6 +35,34 @@ func processNodeAttrID(node *html.Node) {
 	}
 }
 
+func processFootnoteID(ctx *RenderContext, node *html.Node) {
+	for idx, attr := range node.Attr {
+		if attr.Key == "id" {
+			if !isAnchorIDFootnote(attr.Val) {
+				return
+			}
+			if issueNum, ok := ctx.RenderOptions.Metas["issue_comment_id"]; ok {
+				node.Attr[idx].Val = attr.Val + "-" + issueNum
+			}
+			return
+		}
+	}
+}
+
+func processFootnoteBackHref(ctx *RenderContext, node *html.Node) {
+	for idx, attr := range node.Attr {
+		if attr.Key == "href" {
+			if !isAnchorHrefFootnote(attr.Val) {
+				return
+			}
+			if issueNum, ok := ctx.RenderOptions.Metas["issue_comment_id"]; ok {
+				node.Attr[idx].Val = attr.Val + "-" + issueNum
+			}
+			return
+		}
+	}
+}
+
 func processNodeA(ctx *RenderContext, node *html.Node) {
 	for idx, attr := range node.Attr {
 		if attr.Key == "href" {

routers/web/repo/issue_view.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"sort"
+	"strconv"
 
 	activities_model "code.gitea.io/gitea/models/activities"
 	"code.gitea.io/gitea/models/db"
@@ -625,6 +626,7 @@ func prepareIssueViewCommentsAndSidebarParticipants(ctx *context.Context, issue
 
 		if comment.Type == issues_model.CommentTypeComment || comment.Type == issues_model.CommentTypeReview {
 			rctx := renderhelper.NewRenderContextRepoComment(ctx, issue.Repo)
+			rctx.RenderOptions.Metas["issue_comment_id"] = strconv.FormatInt(comment.ID, 10)
 			comment.RenderedContent, err = markdown.RenderString(rctx, comment.Content)
 			if err != nil {
 				ctx.ServerError("RenderString", err)
@@ -982,6 +984,8 @@ func preparePullViewReviewAndMerge(ctx *context.Context, issue *issues_model.Iss
 func prepareIssueViewContent(ctx *context.Context, issue *issues_model.Issue) {
 	var err error
 	rctx := renderhelper.NewRenderContextRepoComment(ctx, ctx.Repo.Repository)
+	// the first issue index set to 0
+	rctx.RenderOptions.Metas["issue_comment_id"] = "0"
 	issue.RenderedContent, err = markdown.RenderString(rctx, issue.Content)
 	if err != nil {
 		ctx.ServerError("RenderString", err)

web_src/js/markup/anchors.ts

@@ -6,7 +6,8 @@ const hasPrefix = (str: string): boolean => str.startsWith('user-content-');
 
 // scroll to anchor while respecting the `user-content` prefix that exists on the target
 function scrollToAnchor(encodedId: string): void {
-  if (!encodedId) return;
+  // Ignore the footnote case, as the link is rendered by the backend.
+  if (!encodedId || encodedId.startsWith('fn:') || encodedId.startsWith('fnref:')) return;
   const id = decodeURIComponent(encodedId);
   const prefixedId = addPrefix(id);
   let el = document.querySelector(`#${prefixedId}`);