bpo-30485: Change the prefix for defining the default namespace in ElementPath from None to '' since there is existing code that uses that and it's more convenient to have an all-string-keys dict (e.g. when sorting items etc.). (#12860)
diff --git a/Doc/library/xml.etree.elementtree.rst b/Doc/library/xml.etree.elementtree.rst
index c83e719..9e2c295 100644
--- a/Doc/library/xml.etree.elementtree.rst
+++ b/Doc/library/xml.etree.elementtree.rst
@@ -764,7 +764,7 @@
Finds the first subelement matching *match*. *match* may be a tag name
or a :ref:`path <elementtree-xpath>`. Returns an element instance
or ``None``. *namespaces* is an optional mapping from namespace prefix
- to full name. Pass ``None`` as prefix to move all unprefixed tag names
+ to full name. Pass ``''`` as prefix to move all unprefixed tag names
in the expression into the given namespace.
@@ -773,7 +773,7 @@
Finds all matching subelements, by tag name or
:ref:`path <elementtree-xpath>`. Returns a list containing all matching
elements in document order. *namespaces* is an optional mapping from
- namespace prefix to full name. Pass ``None`` as prefix to move all
+ namespace prefix to full name. Pass ``''`` as prefix to move all
unprefixed tag names in the expression into the given namespace.
@@ -784,7 +784,7 @@
of the first matching element, or *default* if no element was found.
Note that if the matching element has no text content an empty string
is returned. *namespaces* is an optional mapping from namespace prefix
- to full name. Pass ``None`` as prefix to move all unprefixed tag names
+ to full name. Pass ``''`` as prefix to move all unprefixed tag names
in the expression into the given namespace.
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
index f5b118b..14ce32a 100644
--- a/Lib/test/test_xml_etree.py
+++ b/Lib/test/test_xml_etree.py
@@ -2463,7 +2463,7 @@
nsmap = {'xx': 'Y'}
self.assertEqual(len(root.findall(".//xx:b", namespaces=nsmap)), 1)
self.assertEqual(len(root.findall(".//b", namespaces=nsmap)), 2)
- nsmap = {'xx': 'X', None: 'Y'}
+ nsmap = {'xx': 'X', '': 'Y'}
self.assertEqual(len(root.findall(".//xx:b", namespaces=nsmap)), 2)
self.assertEqual(len(root.findall(".//b", namespaces=nsmap)), 1)
diff --git a/Lib/xml/etree/ElementPath.py b/Lib/xml/etree/ElementPath.py
index 4d231a7..b670d58 100644
--- a/Lib/xml/etree/ElementPath.py
+++ b/Lib/xml/etree/ElementPath.py
@@ -71,7 +71,7 @@
)
def xpath_tokenizer(pattern, namespaces=None):
- default_namespace = namespaces.get(None) if namespaces else None
+ default_namespace = namespaces.get('') if namespaces else None
for token in xpath_tokenizer_re.findall(pattern):
tag = token[1]
if tag and tag[0] != "{":
@@ -275,11 +275,7 @@
cache_key = (path,)
if namespaces:
- if None in namespaces:
- cache_key += (namespaces[None],) + tuple(sorted(
- item for item in namespaces.items() if item[0] is not None))
- else:
- cache_key += tuple(sorted(namespaces.items()))
+ cache_key += tuple(sorted(namespaces.items()))
try:
selector = _cache[cache_key]
diff --git a/Misc/NEWS.d/next/Library/2019-04-13-23-42-33.bpo-30485.JHhjJS.rst b/Misc/NEWS.d/next/Library/2019-04-13-23-42-33.bpo-30485.JHhjJS.rst
index 6c82efd..900edf8 100644
--- a/Misc/NEWS.d/next/Library/2019-04-13-23-42-33.bpo-30485.JHhjJS.rst
+++ b/Misc/NEWS.d/next/Library/2019-04-13-23-42-33.bpo-30485.JHhjJS.rst
@@ -1,3 +1,3 @@
Path expressions in xml.etree.ElementTree can now avoid explicit namespace
prefixes for tags (or the "{namespace}tag" notation) by passing a default
-namespace with a 'None' prefix.
+namespace with an empty string prefix.