Issue #5463: Remove _PY_STRUCT_RANGE_CHECKING constant from struct

module, and remove associated code from test_struct.  This was a
mechanism for skipping some of the tests for overflow behaviour when
packing integers; it's no longer necessary.

Doc/library/struct.rst

@@ -134,6 +134,16 @@ make it fit. For unpacking, the resulting bytes object always has exactly the
 specified number of bytes.  As a special case, ``'0s'`` means a single, empty
 string (while ``'0c'`` means 0 characters).
 
+When packing a value ``x`` using one of the integer formats (``'b'``,
+``'B'``, ``'h'``, ``'H'``, ``'i'``, ``'I'``, ``'l'``, ``'L'``,
+``'q'``, ``'Q'``), if ``x`` is outside the valid range for that format
+then :exc:`struct.error` is raised.
+
+.. versionchanged:: 3.1
+   In 3.0, some of the integer formats wrapped out-of-range values and
+   raised :exc:`DeprecationWarning` instead of :exc:`struct.error`.
+
+
 The ``'p'`` format character encodes a "Pascal string", meaning a short
 variable-length string stored in a fixed number of bytes. The count is the total
 number of bytes stored.  The first byte stored is the length of the string, or

Lib/test/test_struct.py

@@ -14,10 +14,8 @@ del sys
 try:
     import _struct
 except ImportError:
-    PY_STRUCT_RANGE_CHECKING = 0
     PY_STRUCT_FLOAT_COERCE = 2
 else:
-    PY_STRUCT_RANGE_CHECKING = getattr(_struct, '_PY_STRUCT_RANGE_CHECKING', 0)
     PY_STRUCT_FLOAT_COERCE = getattr(_struct, '_PY_STRUCT_FLOAT_COERCE', 0)
 
 def string_reverse(s):
@@ -40,20 +38,6 @@ def with_warning_restore(func):
             return func(*args, **kw)
     return decorator
 
-@with_warning_restore
-def deprecated_err(func, *args):
-    try:
-        func(*args)
-    except (struct.error, OverflowError):
-        pass
-    except DeprecationWarning:
-        raise TestFailed("%s%s expected to raise DeprecationWarning" % (
-                func.__name__, args))
-    else:
-        raise TestFailed("%s%s did not raise error" % (
-            func.__name__, args))
-
-
 class StructTest(unittest.TestCase):
 
     @with_warning_restore
@@ -222,12 +206,6 @@ class StructTest(unittest.TestCase):
 
         class IntTester(unittest.TestCase):
 
-            # XXX Most std integer modes fail to test for out-of-range.
-            # The "i" and "l" codes appear to range-check OK on 32-bit boxes, but
-            # fail to check correctly on some 64-bit ones (Tru64 Unix + Compaq C
-            # reported by Mark Favas).
-            BUGGY_RANGE_CHECK = "bBhHiIlL"
-
             def __init__(self, formatpair, bytesize):
                 self.assertEqual(len(formatpair), 2)
                 self.formatpair = formatpair
@@ -291,12 +269,10 @@ class StructTest(unittest.TestCase):
 
                 else:
                     # x is out of range -- verify pack realizes that.
-                    if not PY_STRUCT_RANGE_CHECKING and code in self.BUGGY_RANGE_CHECK:
-                        if verbose:
-                            print("Skipping buggy range check for code", code)
-                    else:
-                        deprecated_err(pack, ">" + code, x)
-                        deprecated_err(pack, "<" + code, x)
+                    self.assertRaises((struct.error, OverflowError),
+                                      pack, ">" + code, x)
+                    self.assertRaises((struct.error, OverflowError),
+                                      pack, "<" + code, x)
 
                 # Much the same for unsigned.
                 code = self.unsigned_code
@@ -340,12 +316,10 @@ class StructTest(unittest.TestCase):
 
                 else:
                     # x is out of range -- verify pack realizes that.
-                    if not PY_STRUCT_RANGE_CHECKING and code in self.BUGGY_RANGE_CHECK:
-                        if verbose:
-                            print("Skipping buggy range check for code", code)
-                    else:
-                        deprecated_err(pack, ">" + code, x)
-                        deprecated_err(pack, "<" + code, x)
+                    self.assertRaises((struct.error, OverflowError),
+                                      pack, ">" + code, x)
+                    self.assertRaises((struct.error, OverflowError),
+                                      pack, "<" + code, x)
 
             def run(self):
                 from random import randrange
@@ -443,20 +417,24 @@ class StructTest(unittest.TestCase):
         big = math.ldexp(big, 127 - 24)
         self.assertRaises(OverflowError, struct.pack, ">f", big)
 
-    if PY_STRUCT_RANGE_CHECKING:
-        def test_1229380(self):
-            # SF bug 1229380. No struct.pack exception for some out of
-            # range integers
-            import sys
-            for endian in ('', '>', '<'):
-                for fmt in ('B', 'H', 'I', 'L'):
-                    deprecated_err(struct.pack, endian + fmt, -1)
-
-                deprecated_err(struct.pack, endian + 'B', 300)
-                deprecated_err(struct.pack, endian + 'H', 70000)
-
-                deprecated_err(struct.pack, endian + 'I', sys.maxsize * 4)
-                deprecated_err(struct.pack, endian + 'L', sys.maxsize * 4)
+    def test_1229380(self):
+        # SF bug 1229380. No struct.pack exception for some out of
+        # range integers
+        import sys
+        for endian in ('', '>', '<'):
+            for fmt in ('B', 'H', 'I', 'L'):
+                self.assertRaises((struct.error, OverflowError), struct.pack,
+                                  endian + fmt, -1)
+
+            self.assertRaises((struct.error, OverflowError), struct.pack,
+                              endian + 'B', 300)
+            self.assertRaises((struct.error, OverflowError), struct.pack,
+                              endian + 'H', 70000)
+
+            self.assertRaises((struct.error, OverflowError), struct.pack,
+                              endian + 'I', sys.maxsize * 4)
+            self.assertRaises((struct.error, OverflowError), struct.pack,
+                              endian + 'L', sys.maxsize * 4)
 
     def XXXtest_1530559(self):
         # XXX This is broken: see the bug report

Misc/NEWS

@@ -73,7 +73,9 @@ Extension Modules
 
 - Issue #5463: In struct module, remove deprecated overflow wrapping
   when packing an integer: struct.pack('=L', -1) now raises
-  struct.error instead of returning b'\xff\xff\xff\xff'.
+  struct.error instead of returning b'\xff\xff\xff\xff'.  The
+  _PY_STRUCT_RANGE_CHECKING and _PY_STRUCT_OVERFLOW_MASKING constants
+  have been removed from the struct module.
 
 
 What's New in Python 3.1 alpha 1

Modules/_struct.c

@@ -2028,7 +2028,6 @@ PyInit__struct(void)
 
 	PyModule_AddObject(m, "__version__", ver);
 
-	PyModule_AddIntConstant(m, "_PY_STRUCT_RANGE_CHECKING", 1);
 #ifdef PY_STRUCT_FLOAT_COERCE
 	PyModule_AddIntConstant(m, "_PY_STRUCT_FLOAT_COERCE", 1);
 #endif