<p>Assigning to <code>tags</code> is enough to trigger deletion of the old tags I take it?</p>
<p>There is of course a fundamental difference between traces and other objects in that we don't keep multiple versions of traces - so it makes sense to have <code>from_xml</code> on a node be a constructor that creates the new object we are going to save that replaces the current version. Though I guess we don't keep history for changesets either.</p>
<p>I certainly think that if we go this route we should change the method name to <code>update_from_xml</code> or something so that we don't different models using the same name in different ways.</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br />You are receiving this because you are subscribed to this thread.<br />Reply to this email directly, <a href="https://github.com/openstreetmap/openstreetmap-website/pull/1614#issuecomment-323310333">view it on GitHub</a>, or <a href="https://github.com/notifications/unsubscribe-auth/ABWnLfTBLzZ0EmHhTyLSOqU0bzhAh0EEks5sZV2EgaJpZM4O7TcD">mute the thread</a>.<img alt="" height="1" src="https://github.com/notifications/beacon/ABWnLbVcTQl7T7EZ52VVtRYesIJ0ETtgks5sZV2EgaJpZM4O7TcD.gif" width="1" /></p>
<div itemscope itemtype="http://schema.org/EmailMessage">
<div itemprop="action" itemscope itemtype="http://schema.org/ViewAction">
  <link itemprop="url" href="https://github.com/openstreetmap/openstreetmap-website/pull/1614#issuecomment-323310333"></link>
  <meta itemprop="name" content="View Pull Request"></meta>
</div>
<meta itemprop="description" content="View this Pull Request on GitHub"></meta>
</div>

<script type="application/json" data-scope="inboxmarkup">{"api_version":"1.0","publisher":{"api_key":"05dde50f1d1a384dd78767c55493e4bb","name":"GitHub"},"entity":{"external_key":"github/openstreetmap/openstreetmap-website","title":"openstreetmap/openstreetmap-website","subtitle":"GitHub repository","main_image_url":"https://cloud.githubusercontent.com/assets/143418/17495839/a5054eac-5d88-11e6-95fc-7290892c7bb5.png","avatar_image_url":"https://cloud.githubusercontent.com/assets/143418/15842166/7c72db34-2c0b-11e6-9aed-b52498112777.png","action":{"name":"Open in GitHub","url":"https://github.com/openstreetmap/openstreetmap-website"}},"updates":{"snippets":[{"icon":"PERSON","message":"@tomhughes in #1614: Assigning to `tags` is enough to trigger deletion of the old tags I take it?\r\n\r\nThere is of course a fundamental difference between traces and other objects in that we don't keep multiple versions of traces - so it makes sense to have `from_xml` on a node be a constructor that creates the new object we are going to save that replaces the current version. Though I guess we don't keep history for changesets either.\r\n\r\nI certainly think that if we go this route we should change the method name to `update_from_xml` or something so that we don't different models using the same name in different ways."}],"action":{"name":"View Pull Request","url":"https://github.com/openstreetmap/openstreetmap-website/pull/1614#issuecomment-323310333"}}}</script>