SF #660455 : patch by NNorwitz.

gvanrossum · gvanrossum · commit 66b1259dbc2c · 2003-02-12T16:57:47.000Z
"Unsigned" (i.e., positive-looking, but really negative) hex/oct
constants with a leading minus sign are once again properly negated.
The micro-optimization for negated numeric constants did the wrong
thing for such hex/oct constants.  The patch avoids the optimization
for all hex/oct constants.

This needs to be backported to Python 2.2!
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
@@ -133,9 +133,12 @@ def expect_same(test_source, expected):
 expect_same("000000000000008.", 8.)
 expect_same("000000000000009.", 9.)
 
-## # Verify treatment of unary minus on negative numbers SF bug #660455
-## import warnings
-## warnings.filterwarnings("ignore", "hex/oct constants", FutureWarning)
-## # XXX Of course the following test will have to be changed in Python 2.4
-## expect_same("0xffffffff", -1)
-## expect_same("-0xffffffff", 1)
+# Verify treatment of unary minus on negative numbers SF bug #660455
+import warnings
+warnings.filterwarnings("ignore", "hex/oct constants", FutureWarning)
+# XXX Of course the following test will have to be changed in Python 2.4
+# This test is in a <string> so the filterwarnings() can affect it
+exec """
+expect_same("0xffffffff", -1)
+expect_same("-0xffffffff", 1)
+"""
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
@@ -37,7 +37,9 @@
 except ImportError:
     maxint = 2147483647
 if maxint == 2147483647:
-    if -2147483647-1 != -020000000000: raise TestFailed, 'max negative int'
+    # The following test will start to fail in Python 2.4;
+    # change the 020000000000 to -020000000000
+    if -2147483647-1 != 020000000000: raise TestFailed, 'max negative int'
     # XXX -2147483648
     if 037777777777 != -1: raise TestFailed, 'oct -1'
     if 0xffffffff != -1: raise TestFailed, 'hex -1'
diff --git a/Python/compile.c b/Python/compile.c
@@ -2069,7 +2069,8 @@ com_factor(struct compiling *c, node *n)
  	    && NCH(ppower) == 1
 	    && TYPE((patom = CHILD(ppower, 0))) == atom
 	    && TYPE((pnum = CHILD(patom, 0))) == NUMBER
-	    && !(childtype == MINUS && is_float_zero(STR(pnum)))) {
+	    && !(childtype == MINUS &&
+		 (STR(pnum)[0] == '0' || is_float_zero(STR(pnum))))) {
 		if (childtype == TILDE) {
 			com_invert_constant(c, pnum);
 			return;
