_exceptions: Format a missing system id as <unknown>.

expatreader: Use the error handler instead of raising exception directly.

Lib/xml/sax/_exceptions.py

@@ -79,10 +79,11 @@ class SAXParseException(SAXException):
 
     def __str__(self):
         "Create a string representation of the exception."
-        return "%s at %s:%d:%d" % (self._msg,
-                                   self.getSystemId(),
-                                   self.getLineNumber(),
-                                   self.getColumnNumber())
+        sysid = self.getSystemId()
+        if sysid is None:
+            sysid = "<unknown>"
+        return "%s:%d:%d: %s" % (sysid, self.getLineNumber(),
+                                 self.getColumnNumber(), self._msg)
 
 
 # ===== SAXNOTRECOGNIZEDEXCEPTION =====

Lib/xml/sax/expatreader.py

@@ -81,7 +81,8 @@ class ExpatParser(xmlreader.IncrementalParser, xmlreader.Locator):
             self._parser.Parse(data, isFinal)
         except expat.error:
             error_code = self._parser.ErrorCode
-            raise SAXParseException(expat.ErrorString(error_code), None, self)
+            exc = SAXParseException(expat.ErrorString(error_code), None, self)
+            self._err_handler.fatalError(exc)
 
     def close(self):
         if self._entity_stack: