NPE in ImageNode class when images do not have a src attribute

When the html code of a rich text field contains an <img> tag that does not have an src attribute, the CMS hangs and the editor cannot continue to work. This is due to a NPE that occurs in a class that is used to create the html diff of the rich text field for the compare mode.

The NPE occurs in org.outerj.daisy.diff.html.dom.ImageNode#ImageNode, where attrs.getValue("src") in this case is null.

Example of img tag without src attribute:

<picture> <source media="(max-width: 767px)" srcset="/binaries/content/gallery/myhippoproject/samples/viognier-grapes-188185_640.jpg" /> <span id="cke_bm_276S" style="display: none;"> </span><img alt="Some alt text" class="banner-image" srcset="/binaries/content/gallery/myhippoproject/samples/viognier-grapes-188185_640.jpg" /><span id="cke_bm_276E" style="display: none;"> </span> </picture>