title: Do I have to persist object from repository in Doctrine?
body: <p>Do I have to persist the object I fetched from a repository? For example:</p>
  <pre><code>$foo = $this-&gt;repository-&gt;find($id);
  $foo-&gt;setBar($baz);
  
  $this-&gt;flush();
  </code></pre>
  <p>Do I have to add <code>$this-&gt;persist($foo);</code>? When I don't have to persist changes?</p>