Make blockquote attention recognize more syntaxes (#31240) (#31250)

Backport #31240 by wxiaoguang

Fix #31214

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/markup/markdown/markdown_test.go

@@ -1010,4 +1010,10 @@ func TestAttention(t *testing.T) {
 	test(`> [!important]`, renderAttention("important", "octicon-report")+"\n</blockquote>")
 	test(`> [!warning]`, renderAttention("warning", "octicon-alert")+"\n</blockquote>")
 	test(`> [!caution]`, renderAttention("caution", "octicon-stop")+"\n</blockquote>")
+
+	// escaped by mdformat
+	test(`> \[!NOTE\]`, renderAttention("note", "octicon-info")+"\n</blockquote>")
+
+	// legacy GitHub style
+	test(`> **warning**`, renderAttention("warning", "octicon-alert")+"\n</blockquote>")
 }

modules/markup/markdown/math/block_parser.go

@@ -31,10 +31,16 @@ func (b *blockParser) Open(parent ast.Node, reader text.Reader, pc parser.Contex
 		return nil, parser.NoChildren
 	}
 
-	dollars := false
+	var dollars bool
 	if b.parseDollars && line[pos] == '$' && line[pos+1] == '$' {
 		dollars = true
-	} else if line[pos] != '\\' || line[pos+1] != '[' {
+	} else if line[pos] == '\\' && line[pos+1] == '[' {
+		if len(line[pos:]) >= 3 && line[pos+2] == '!' && bytes.Contains(line[pos:], []byte(`\]`)) {
+			// do not process escaped attention block: "> \[!NOTE\]"
+			return nil, parser.NoChildren
+		}
+		dollars = false
+	} else {
 		return nil, parser.NoChildren
 	}
 

modules/markup/markdown/transform_blockquote.go

@@ -15,7 +15,7 @@ import (
 	"golang.org/x/text/language"
 )
 
-// renderAttention renders a quote marked with i.e. "> **Note**" or "> **Warning**" with a corresponding svg
+// renderAttention renders a quote marked with i.e. "> **Note**" or "> [!Warning]" with a corresponding svg
 func (r *HTMLRenderer) renderAttention(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	if entering {
 		n := node.(*Attention)
@@ -37,38 +37,93 @@ func (r *HTMLRenderer) renderAttention(w util.BufWriter, source []byte, node ast
 	return ast.WalkContinue, nil
 }
 
-func (g *ASTTransformer) transformBlockquote(v *ast.Blockquote, reader text.Reader) (ast.WalkStatus, error) {
-	// We only want attention blockquotes when the AST looks like:
-	// > Text("[") Text("!TYPE") Text("]")
+func (g *ASTTransformer) extractBlockquoteAttentionEmphasis(firstParagraph ast.Node, reader text.Reader) (string, []ast.Node) {
+	if firstParagraph.ChildCount() < 1 {
+		return "", nil
+	}
+	node1, ok := firstParagraph.FirstChild().(*ast.Emphasis)
+	if !ok {
+		return "", nil
+	}
+	val1 := string(node1.Text(reader.Source()))
+	attentionType := strings.ToLower(val1)
+	if g.attentionTypes.Contains(attentionType) {
+		return attentionType, []ast.Node{node1}
+	}
+	return "", nil
+}
 
-	// grab these nodes and make sure we adhere to the attention blockquote structure
-	firstParagraph := v.FirstChild()
-	g.applyElementDir(firstParagraph)
-	if firstParagraph.ChildCount() < 3 {
-		return ast.WalkContinue, nil
+func (g *ASTTransformer) extractBlockquoteAttention2(firstParagraph ast.Node, reader text.Reader) (string, []ast.Node) {
+	if firstParagraph.ChildCount() < 2 {
+		return "", nil
 	}
 	node1, ok := firstParagraph.FirstChild().(*ast.Text)
 	if !ok {
-		return ast.WalkContinue, nil
+		return "", nil
 	}
 	node2, ok := node1.NextSibling().(*ast.Text)
 	if !ok {
-		return ast.WalkContinue, nil
+		return "", nil
+	}
+	val1 := string(node1.Segment.Value(reader.Source()))
+	val2 := string(node2.Segment.Value(reader.Source()))
+	if strings.HasPrefix(val1, `\[!`) && val2 == `\]` {
+		attentionType := strings.ToLower(val1[3:])
+		if g.attentionTypes.Contains(attentionType) {
+			return attentionType, []ast.Node{node1, node2}
+		}
+	}
+	return "", nil
+}
+
+func (g *ASTTransformer) extractBlockquoteAttention3(firstParagraph ast.Node, reader text.Reader) (string, []ast.Node) {
+	if firstParagraph.ChildCount() < 3 {
+		return "", nil
+	}
+	node1, ok := firstParagraph.FirstChild().(*ast.Text)
+	if !ok {
+		return "", nil
+	}
+	node2, ok := node1.NextSibling().(*ast.Text)
+	if !ok {
+		return "", nil
 	}
 	node3, ok := node2.NextSibling().(*ast.Text)
 	if !ok {
-		return ast.WalkContinue, nil
+		return "", nil
 	}
 	val1 := string(node1.Segment.Value(reader.Source()))
 	val2 := string(node2.Segment.Value(reader.Source()))
 	val3 := string(node3.Segment.Value(reader.Source()))
 	if val1 != "[" || val3 != "]" || !strings.HasPrefix(val2, "!") {
-		return ast.WalkContinue, nil
+		return "", nil
 	}
 
-	// grab attention type from markdown source
 	attentionType := strings.ToLower(val2[1:])
-	if !g.attentionTypes.Contains(attentionType) {
+	if g.attentionTypes.Contains(attentionType) {
+		return attentionType, []ast.Node{node1, node2, node3}
+	}
+	return "", nil
+}
+
+func (g *ASTTransformer) transformBlockquote(v *ast.Blockquote, reader text.Reader) (ast.WalkStatus, error) {
+	// We only want attention blockquotes when the AST looks like:
+	// > Text("[") Text("!TYPE") Text("]")
+	// > Text("\[!TYPE") TEXT("\]")
+	// > Text("**TYPE**")
+
+	// grab these nodes and make sure we adhere to the attention blockquote structure
+	firstParagraph := v.FirstChild()
+	g.applyElementDir(firstParagraph)
+
+	attentionType, processedNodes := g.extractBlockquoteAttentionEmphasis(firstParagraph, reader)
+	if attentionType == "" {
+		attentionType, processedNodes = g.extractBlockquoteAttention2(firstParagraph, reader)
+	}
+	if attentionType == "" {
+		attentionType, processedNodes = g.extractBlockquoteAttention3(firstParagraph, reader)
+	}
+	if attentionType == "" {
 		return ast.WalkContinue, nil
 	}
 
@@ -88,9 +143,9 @@ func (g *ASTTransformer) transformBlockquote(v *ast.Blockquote, reader text.Read
 	attentionParagraph.AppendChild(attentionParagraph, NewAttention(attentionType))
 	attentionParagraph.AppendChild(attentionParagraph, emphasis)
 	firstParagraph.Parent().InsertBefore(firstParagraph.Parent(), firstParagraph, attentionParagraph)
-	firstParagraph.RemoveChild(firstParagraph, node1)
-	firstParagraph.RemoveChild(firstParagraph, node2)
-	firstParagraph.RemoveChild(firstParagraph, node3)
+	for _, processed := range processedNodes {
+		firstParagraph.RemoveChild(firstParagraph, processed)
+	}
 	if firstParagraph.ChildCount() == 0 {
 		firstParagraph.Parent().RemoveChild(firstParagraph.Parent(), firstParagraph)
 	}