Issue #18896: Python function can now have more than 255 parameters.

collections.namedtuple() now supports tuples with more than 255 elements.

Lib/test/test_collections.py

@@ -319,8 +319,7 @@ class TestNamedTuple(unittest.TestCase):
         self.assertEqual(Dot(1)._replace(d=999), (999,))
         self.assertEqual(Dot(1)._fields, ('d',))
 
-        # n = 5000
-        n = 254 # SyntaxError: more than 255 arguments:
+        n = 5000
         names = list(set(''.join([choice(string.ascii_letters)
                                   for j in range(10)]) for i in range(n)))
         n = len(names)

Lib/test/test_compile.py

@@ -401,16 +401,9 @@ if 1:
         self.assertNotIn((Ellipsis, Ellipsis), d)
 
     def test_annotation_limit(self):
-        # 16 bits are available for # of annotations, but only 8 bits are
-        # available for the parameter count, hence 255
-        # is the max. Ensure the result of too many annotations is a
-        # SyntaxError.
+        # more than 255 annotations, should compile ok
         s = "def f(%s): pass"
-        s %= ', '.join('a%d:%d' % (i,i) for i in range(256))
-        self.assertRaises(SyntaxError, compile, s, '?', 'exec')
-        # Test that the max # of annotations compiles.
-        s = "def f(%s): pass"
-        s %= ', '.join('a%d:%d' % (i,i) for i in range(255))
+        s %= ', '.join('a%d:%d' % (i,i) for i in range(300))
         compile(s, '?', 'exec')
 
     def test_mangling(self):

Lib/test/test_keywordonlyarg.py

@@ -51,24 +51,12 @@ class KeywordOnlyArgTestCase(unittest.TestCase):
         self.assertRaisesSyntaxError("def f(p, *, (k1, k2), **kw):\n  pass\n")
 
     def testSyntaxForManyArguments(self):
-        fundef = "def f("
-        for i in range(255):
-            fundef += "i%d, "%i
-        fundef += "*, key=100):\n pass\n"
-        self.assertRaisesSyntaxError(fundef)
-
-        fundef2 = "def foo(i,*,"
-        for i in range(255):
-            fundef2 += "i%d, "%i
-        fundef2 += "lastarg):\n  pass\n"
-        self.assertRaisesSyntaxError(fundef2)
-
-        # exactly 255 arguments, should compile ok
-        fundef3 = "def f(i,*,"
-        for i in range(253):
-            fundef3 += "i%d, "%i
-        fundef3 += "lastarg):\n  pass\n"
-        compile(fundef3, "<test>", "single")
+        # more than 255 positional arguments, should compile ok
+        fundef = "def f(%s):\n  pass\n" % ', '.join('i%d' % i for i in range(300))
+        compile(fundef, "<test>", "single")
+        # more than 255 keyword-only arguments, should compile ok
+        fundef = "def f(*, %s):\n  pass\n" % ', '.join('i%d' % i for i in range(300))
+        compile(fundef, "<test>", "single")
 
     def testTooManyPositionalErrorMessage(self):
         def f(a, b=None, *, c=None):

Lib/test/test_sys.py

@@ -926,7 +926,7 @@ class SizeofTest(unittest.TestCase):
             def inner():
                 return x
             return inner
-        check(get_cell2.__code__, size('6i13P') + 1)
+        check(get_cell2.__code__, size('6i13P') + calcsize('n'))
         # complex
         check(complex(0,1), size('2d'))
         # method_descriptor (descriptor object)