address review: use z option for twos complement interpretation

Author: skirpichev

Lib/test/test_format.py

@@ -620,9 +620,10 @@ def test_specifier_z_error(self):
         with self.assertRaisesRegex(ValueError, error_msg):
             f"{0:fz}"  # wrong position
 
-        error_msg = re.escape("Negative zero coercion (z) not allowed")
+        error_msg = re.escape("'z' option not allowed with 'c', 'd' and 'n'")
         with self.assertRaisesRegex(ValueError, error_msg):
             f"{0:zd}"  # can't apply to int presentation type
+        error_msg = re.escape("Negative zero coercion (z) not allowed")
         with self.assertRaisesRegex(ValueError, error_msg):
             f"{'x':zs}"  # can't apply to string
 

Lib/test/test_long.py

@@ -707,9 +707,9 @@ def test__format__(self):
         self.assertRaises(ValueError, format, 1234567890, ',x')
         self.assertEqual(format(1234567890, '_x'), '4996_02d2')
         self.assertEqual(format(1234567890, '_X'), '4996_02D2')
-        self.assertEqual(format(8086, '#.8x'), '0x00001f96')
-        self.assertEqual(format(2048, '.3x'), '0800')
-        self.assertEqual(format(-2049, '.3x'), '17ff')
+        self.assertEqual(format(8086, 'z#.8x'), '0x00001f96')
+        self.assertEqual(format(2048, 'z.3x'), '0800')
+        self.assertEqual(format(-2049, 'z.3x'), '17ff')
 
         # octal
         self.assertEqual(format(3, "o"), "3")
@@ -724,9 +724,9 @@ def test__format__(self):
         self.assertEqual(format(-1234, "+o"), "-2322")
         self.assertRaises(ValueError, format, 1234567890, ',o')
         self.assertEqual(format(1234567890, '_o'), '111_4540_1322')
-        self.assertEqual(format(18, '#.3o'), '0o022')
-        self.assertEqual(format(256, '.3o'), '0400')
-        self.assertEqual(format(-257, '.3o'), '1377')
+        self.assertEqual(format(18, 'z#.3o'), '0o022')
+        self.assertEqual(format(256, 'z.3o'), '0400')
+        self.assertEqual(format(-257, 'z.3o'), '1377')
 
         # binary
         self.assertEqual(format(3, "b"), "11")
@@ -741,13 +741,13 @@ def test__format__(self):
         self.assertEqual(format(-1234, "+b"), "-10011010010")
         self.assertRaises(ValueError, format, 1234567890, ',b')
         self.assertEqual(format(12345, '_b'), '11_0000_0011_1001')
-        self.assertEqual(format(-12, '.8b'), '11110100')
-        self.assertEqual(format(73, '.8b'), '01001001')
-        self.assertEqual(format(73, '#.8b'), '0b01001001')
-        self.assertEqual(format(300, '.8b'), '100101100')
-        self.assertEqual(format(-200, '.8b'), '100111000')
-        self.assertEqual(format(128, '.8b'), '010000000')
-        self.assertEqual(format(-129, '.8b'), '101111111')
+        self.assertEqual(format(-12, 'z.8b'), '11110100')
+        self.assertEqual(format(73, 'z.8b'), '01001001')
+        self.assertEqual(format(73, 'z#.8b'), '0b01001001')
+        self.assertEqual(format(300, 'z.8b'), '100101100')
+        self.assertEqual(format(-200, 'z.8b'), '100111000')
+        self.assertEqual(format(128, 'z.8b'), '010000000')
+        self.assertEqual(format(-129, 'z.8b'), '101111111')
 
         # make sure these are errors
         self.assertRaises(ValueError, format, 3, "1.3c")  # precision disallowed with 'c',

Python/formatter_unicode.c

@@ -988,10 +988,12 @@ format_long_internal(PyObject *value, const InternalFormatSpec *format,
     }
 
     /* no negative zero coercion on integers */
-    if (format->no_neg_0) {
+    if (format->no_neg_0 && format->type != 'b' && format->type != 'o'
+        && format->type != 'x' && format->type != 'X')
+    {
         PyErr_SetString(PyExc_ValueError,
-                        "Negative zero coercion (z) not allowed in integer"
-                        " format specifier");
+                        "'z' option not allowed with 'c', 'd' and 'n' "
+                        "integer format specifier");
         goto done;
     }
 
@@ -1084,8 +1086,9 @@ format_long_internal(PyObject *value, const InternalFormatSpec *format,
             int64_t precision = Py_MAX(1, format->precision);
 
             /* Use two's complement for 'b', 'o' and 'x' formatting types */
-            if (format->type == 'b' || format->type == 'x'
-                || format->type == 'o' || format->type == 'X')
+            if (format->no_neg_0 && (format->type == 'b' || format->type == 'x'
+                                     || format->type == 'o'
+                                     || format->type == 'X'))
             {
                 int64_t shift = precision;
                 int incr = 1;