backslash in image "alt" attribute

[JohannesKaufmann]

Goldmark is a really solid library, thanks a lot for making it!

This bug is not really important, the user won't really notice. But it differs from the CommonMark implementation, so I wanted to report it nevertheless.

• \ backslash used for escaping
• ` backtick used for code

Background

First, I learned that an unescaped backtick in the image alt could (accidentally) trigger an inline code. By escaping the backtick, the markdown renders correctly (see Screenshot 1).

However the behaviour of the CommonMark Demo and Goldmark differ. In Goldmark the \ backslash stays in the rendered html (see Screenshot 2).

This causes the backslash to unexpectedly render in the browser (see Screenshot 3).

Steps to Reproduce

source := []byte("![\\`alt](https://example.com/img.png)")

var buf bytes.Buffer
if err := goldmark.Convert(source, &buf); err != nil {
  panic(err)
}

fmt.Println(buf.String())
// Got:       <p><img src="https://example.com/img.png" alt="\`alt"></p>
// Expected:  <p><img src="https://example.com/img.png" alt="`alt" /></p>

1. What version of goldmark are you using? : v1.7.2
2. What version of Go are you using? : 1.21
3. What operating system and processor architecture are you using? : MacOS ARM