Merge pull request #2219 from alixander/markdown-comment

markdown: sanitize links

ci/release/changelogs/next.md

@@ -9,3 +9,4 @@
 #### Bugfixes ⛑️
 
 - Imports: fixes using substitutions in `icon` values [#2207](https://github.com/terrastruct/d2/pull/2207)
+- Markdown: fixes ampersands in URLs in markdown [#2219](https://github.com/terrastruct/d2/pull/2219)

d2compiler/compile_test.go

@@ -935,6 +935,13 @@ b.(x -> y)[0]: two
 				}
 			},
 		},
+		{
+			name: "markdown_ampersand",
+			text: `memo: |md
+  <a href="https://www.google.com/search?q=d2&newwindow=1&amp;bar">d2</a>
+|
+`,
+		},
 		{
 			name: "unsemantic_markdown",
 

lib/textmeasure/links.go

@@ -0,0 +1,26 @@
+package textmeasure
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+func sanitizeLinks(input string) (string, error) {
+	re := regexp.MustCompile(`href="([^"]*)"`)
+
+	return re.ReplaceAllStringFunc(input, func(href string) string {
+		matches := re.FindStringSubmatch(href)
+		if len(matches) < 2 {
+			return href
+		}
+
+		value := matches[1]
+
+		value = strings.ReplaceAll(value, "&amp;", "TEMP_AMP")
+		value = strings.ReplaceAll(value, "&", "&amp;")
+		value = strings.ReplaceAll(value, "TEMP_AMP", "&amp;")
+
+		return fmt.Sprintf(`href="%s"`, value)
+	}), nil
+}

lib/textmeasure/markdown.go

@@ -83,7 +83,11 @@ func RenderMarkdown(m string) (string, error) {
 	if err := markdownRenderer.Convert([]byte(m), &output); err != nil {
 		return "", err
 	}
-	return output.String(), nil
+	sanitized, err := sanitizeLinks(output.String())
+	if err != nil {
+		return "", err
+	}
+	return sanitized, nil
 }
 
 func init() {