EPUB Input: Remove non XML documents from the spine automatically, instead of erroring out

src/calibre/ebooks/oeb/reader.py

@@ -321,6 +321,12 @@ class OEBReader(object):
         if len(spine) == 0:
             raise OEBError("Spine is empty")
         self._spine_add_extra()
+        for item in spine:
+            if item.media_type.lower() not in OEB_DOCS:
+                if not hasattr(item.data, 'xpath'):
+                    self.oeb.log.warn('The item %s is not an XML document.'
+                            ' Removing it from spine.'%item.href)
+                    spine.remove(item)
 
     def _guide_from_opf(self, opf):
         guide = self.oeb.guide