Fixed emoji alias not parsed in links (#16221)

* Do not skip links.

* Restrict text in links to emojis.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>

modules/markup/html.go

@@ -322,7 +322,7 @@ func postProcess(ctx *RenderContext, procs []processor, input io.Reader, output
 		node = node.FirstChild
 	}
 
-	visitNode(ctx, procs, node, true)
+	visitNode(ctx, procs, procs, node)
 
 	newNodes := make([]*html.Node, 0, 5)
 
@@ -354,7 +354,7 @@ func postProcess(ctx *RenderContext, procs []processor, input io.Reader, output
 	return nil
 }
 
-func visitNode(ctx *RenderContext, procs []processor, node *html.Node, visitText bool) {
+func visitNode(ctx *RenderContext, procs, textProcs []processor, node *html.Node) {
 	// Add user-content- to IDs if they don't already have them
 	for idx, attr := range node.Attr {
 		if attr.Key == "id" && !(strings.HasPrefix(attr.Val, "user-content-") || blackfridayExtRegex.MatchString(attr.Val)) {
@@ -362,16 +362,14 @@ func visitNode(ctx *RenderContext, procs []processor, node *html.Node, visitText
 		}
 
 		if attr.Key == "class" && attr.Val == "emoji" {
-			visitText = false
+			textProcs = nil
 		}
 	}
 
-	// We ignore code, pre and already generated links.
+	// We ignore code and pre.
 	switch node.Type {
 	case html.TextNode:
-		if visitText {
-			textNode(ctx, procs, node)
-		}
+		textNode(ctx, textProcs, node)
 	case html.ElementNode:
 		if node.Data == "img" {
 			for i, attr := range node.Attr {
@@ -390,7 +388,8 @@ func visitNode(ctx *RenderContext, procs []processor, node *html.Node, visitText
 				node.Attr[i] = attr
 			}
 		} else if node.Data == "a" {
-			visitText = false
+			// Restrict text in links to emojis
+			textProcs = emojiProcessors
 		} else if node.Data == "code" || node.Data == "pre" {
 			return
 		} else if node.Data == "i" {
@@ -416,7 +415,7 @@ func visitNode(ctx *RenderContext, procs []processor, node *html.Node, visitText
 			}
 		}
 		for n := node.FirstChild; n != nil; n = n.NextSibling {
-			visitNode(ctx, procs, n, visitText)
+			visitNode(ctx, procs, textProcs, n)
 		}
 	}
 	// ignore everything else

modules/markup/markdown/markdown_test.go

@@ -391,5 +391,13 @@ func TestRenderSiblingImages_Issue12925(t *testing.T) {
 	res, err := RenderRawString(&markup.RenderContext{}, testcase)
 	assert.NoError(t, err)
 	assert.Equal(t, expected, res)
+}
 
+func TestRenderEmojiInLinks_Issue12331(t *testing.T) {
+	testcase := `[Link with emoji :moon: in text](https://gitea.io)`
+	expected := `<p><a href="https://gitea.io" rel="nofollow">Link with emoji <span class="emoji" aria-label="waxing gibbous moon">🌔</span> in text</a></p>
+`
+	res, err := RenderString(&markup.RenderContext{}, testcase)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, res)
 }