bpo-34789: make xml.sax.make_parser accept iterables of all types (GH-9576)

Doc/library/xml.sax.rst

@@ -40,10 +40,13 @@ The convenience functions are:
 
    Create and return a SAX :class:`~xml.sax.xmlreader.XMLReader` object.  The
    first parser found will
-   be used.  If *parser_list* is provided, it must be a sequence of strings which
+   be used.  If *parser_list* is provided, it must be an iterable of strings which
    name modules that have a function named :func:`create_parser`.  Modules listed
    in *parser_list* will be used before modules in the default list of parsers.
 
+   .. versionchanged:: 3.8
+      The *parser_list* argument can be any iterable, not just a list.
+
 
 .. function:: parse(filename_or_stream, handler, error_handler=handler.ErrorHandler())
 

Lib/test/test_sax.py

@@ -254,6 +254,34 @@ class MakeParserTest(unittest.TestCase):
         from xml.sax import make_parser
         p = make_parser()
 
+    def test_make_parser3(self):
+        # Testing that make_parser can handle different types of
+        # iterables.
+        make_parser(['module'])
+        make_parser(('module', ))
+        make_parser({'module'})
+        make_parser(frozenset({'module'}))
+        make_parser({'module': None})
+        make_parser(iter(['module']))
+
+    def test_make_parser4(self):
+        # Testing that make_parser can handle empty iterables.
+        make_parser([])
+        make_parser(tuple())
+        make_parser(set())
+        make_parser(frozenset())
+        make_parser({})
+        make_parser(iter([]))
+
+    def test_make_parser5(self):
+        # Testing that make_parser can handle iterables with more than
+        # one item.
+        make_parser(['module1', 'module2'])
+        make_parser(('module1', 'module2'))
+        make_parser({'module1', 'module2'})
+        make_parser(frozenset({'module1', 'module2'}))
+        make_parser({'module1': None, 'module2': None})
+        make_parser(iter(['module1', 'module2']))
 
 # ===========================================================================
 #

Lib/xml/sax/__init__.py

@@ -67,15 +67,15 @@ if sys.platform[:4] == "java" and sys.registry.containsKey(_key):
     default_parser_list = sys.registry.getProperty(_key).split(",")
 
 
-def make_parser(parser_list = []):
+def make_parser(parser_list=()):
     """Creates and returns a SAX parser.
 
     Creates the first parser it is able to instantiate of the ones
-    given in the list created by doing parser_list +
-    default_parser_list.  The lists must contain the names of Python
+    given in the iterable created by chaining parser_list and
+    default_parser_list.  The iterables must contain the names of Python
     modules containing both a SAX parser and a create_parser function."""
 
-    for parser_name in parser_list + default_parser_list:
+    for parser_name in list(parser_list) + default_parser_list:
         try:
             return _create_parser(parser_name)
         except ImportError as e:

Misc/NEWS.d/next/Library/2018-09-25-15-48-50.bpo-34789.rPOEj5.rst

+:func:`xml.sax.make_parser` now accepts any iterable as its *parser_list*
+argument.  Patch by Andrés Delfino.