Add SAXReaderNotAvailable, and use it to distinguish between an
ImportError, and a missing driver.
diff --git a/Lib/xml/sax/__init__.py b/Lib/xml/sax/__init__.py
index 1f1f58e..447420e 100644
--- a/Lib/xml/sax/__init__.py
+++ b/Lib/xml/sax/__init__.py
@@ -22,7 +22,8 @@
from xmlreader import InputSource
from handler import ContentHandler, ErrorHandler
from _exceptions import SAXException, SAXNotRecognizedException, \
- SAXParseException, SAXNotSupportedException
+ SAXParseException, SAXNotSupportedException, \
+ SAXReaderNotAvailable
def parse(source, handler, errorHandler=ErrorHandler()):
@@ -74,9 +75,17 @@
try:
return _create_parser(parser_name)
except ImportError,e:
+ import sys
+ if sys.modules.has_key(parser_name):
+ # The parser module was found, but importing it
+ # failed unexpectedly, pass this exception through
+ raise
+ except SAXReaderNotAvailable:
+ # The parser module detected that it won't work properly,
+ # so try the next one
pass
- raise SAXException("No parsers found", None)
+ raise SAXReaderNotAvailable("No parsers found", None)
# --- Internal utility methods used by make_parser
diff --git a/Lib/xml/sax/_exceptions.py b/Lib/xml/sax/_exceptions.py
index c02974f..1804f3f 100644
--- a/Lib/xml/sax/_exceptions.py
+++ b/Lib/xml/sax/_exceptions.py
@@ -104,3 +104,13 @@
perform is requested (specifically setting a state or value). SAX
applications and extensions may use this class for similar
purposes."""
+
+# ===== SAXNOTSUPPORTEDEXCEPTION =====
+
+class SAXReaderNotAvailable(SAXNotSupportedException):
+ """Exception class for a missing driver.
+
+ An XMLReader module (driver) should raise this exception when it
+ is first imported, e.g. when a support module cannot be imported.
+ It also may be raised during parsing, e.g. if executing an external
+ program is not permitted."""
diff --git a/Lib/xml/sax/expatreader.py b/Lib/xml/sax/expatreader.py
index 2fc2b7c..eb46bcd 100644
--- a/Lib/xml/sax/expatreader.py
+++ b/Lib/xml/sax/expatreader.py
@@ -6,7 +6,10 @@
version = "0.20"
from xml.sax._exceptions import *
-from xml.parsers import expat
+try:
+ from xml.parsers import expat
+except ImportError:
+ raise SAXReaderNotAvailable("expat not supported",None)
from xml.sax import xmlreader, saxutils, handler
AttributesImpl = xmlreader.AttributesImpl