import silently fails when opml XML is malformed

Unexpected behavior: UI display "OPML import is happening. It can take a minute. Don't reorganize your feeds until it's completed importing. Refresh to see its progress." — but no feeds appear on refresh, or ever.

Expected behavior: UI displays an error message so the user can fix the problem and try again.

This test case should reproduce the problem. Note the unescaped quotes in attributes.

<?xml version="1.0"?>
<opml version="1.0">
  <head>
    <title>feeds export</title>
  </head>
  <body>
    <outline text="fubar "baz""
        title="fubar "baz"" type="rss"
        xmlUrl="https://example.com/feed"/>
</body>
</opml>

maddyblue / goread

import silently fails when opml XML is malformed #313