Closes #2892: preserve iterparse events in case of SyntaxError.

Lib/test/test_xml_etree.py

@@ -754,6 +754,7 @@ def iterparse():
     ...     print(action, elem.tag)
     ... except ET.ParseError as v:
     ...   print(v)
+    end document
     junk after document element: line 1, column 12
     """
 

Lib/xml/etree/ElementTree.py

@@ -1250,6 +1250,7 @@ class _IterParseIterator:
         self._close_file = close_source
         self._events = []
         self._index = 0
+        self._error = None
         self.root = self._root = None
         self._parser = parser
         # wire up the parser for event reporting
@@ -1291,7 +1292,14 @@ class _IterParseIterator:
         while 1:
             try:
                 item = self._events[self._index]
+                self._index += 1
+                return item
             except IndexError:
+                pass
+            if self._error:
+                e = self._error
+                self._error = None
+                raise e
             if self._parser is None:
                 self.root = self._root
                 if self._close_file:
@@ -1302,13 +1310,13 @@ class _IterParseIterator:
             self._index = 0
             data = self._file.read(16384)
             if data:
+                try:
                     self._parser.feed(data)
+                except SyntaxError as exc:
+                    self._error = exc
             else:
                 self._root = self._parser.close()
                 self._parser = None
-            else:
-                self._index = self._index + 1
-                return item
 
     def __iter__(self):
         return self

Misc/NEWS

@@ -66,6 +66,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #2892: preserve iterparse events in case of SyntaxError.
+
 - Issue #670664: Fix HTMLParser to correctly handle the content of
   ``<script>...</script>`` and ``<style>...</style>``.
 

Modules/_elementtree.c

@@ -3000,6 +3000,7 @@ PyInit__elementtree(void)
         "  self._file = file\n"
         "  self._events = []\n"
         "  self._index = 0\n"
+        "  self._error = None\n"
         "  self.root = self._root = None\n"
         "  b = cElementTree.TreeBuilder()\n"
         "  self._parser = cElementTree.XMLParser(b)\n"
@@ -3008,7 +3009,14 @@ PyInit__elementtree(void)
         "  while 1:\n"
         "    try:\n"
         "      item = self._events[self._index]\n"
+        "      self._index += 1\n"
+        "      return item\n"
         "    except IndexError:\n"
+        "      pass\n"
+        "    if self._error:\n"
+        "      e = self._error\n"
+        "      self._error = None\n"
+        "      raise e\n"
         "    if self._parser is None:\n"
         "      self.root = self._root\n"
         "      if self._close_file:\n"
@@ -3019,13 +3027,13 @@ PyInit__elementtree(void)
         "    self._index = 0\n"
         "    data = self._file.read(16384)\n"
         "    if data:\n"
+        "      try:\n"
         "        self._parser.feed(data)\n"
+        "      except SyntaxError as exc:\n"
+        "        self._error = exc\n"
         "    else:\n"
         "      self._root = self._parser.close()\n"
         "      self._parser = None\n"
-        "    else:\n"
-        "      self._index = self._index + 1\n"
-        "      return item\n"
         " def __iter__(self):\n"
         "  return self\n"
         "cElementTree.iterparse = iterparse\n"