SF bug #477221: abs and divmod act oddly with -0.0.

Partial fix.
float_abs():  ensure abs(-0.0) returns +0.0.
Bugfix candidate.

diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index b8c37721dbeaeb46e712fda81db515e39d704160..82aa963a88de747168f0c3c1854190d73cef6043 100644 (file)
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -114,7 +114,7 @@ PyFloat_FromString(PyObject *v, char **pend)
                }
                if (PyUnicode_EncodeDecimal(PyUnicode_AS_UNICODE(v),
                                            PyUnicode_GET_SIZE(v),
-                                           s_buffer, 
+                                           s_buffer,
                                            NULL))
                        return NULL;
                s = s_buffer;
@@ -196,16 +196,16 @@ PyFloat_AsDouble(PyObject *op)
        PyNumberMethods *nb;
        PyFloatObject *fo;
        double val;
-       
+
        if (op && PyFloat_Check(op))
                return PyFloat_AS_DOUBLE((PyFloatObject*) op);
-       
+
        if (op == NULL || (nb = op->ob_type->tp_as_number) == NULL ||
            nb->nb_float == NULL) {
                PyErr_BadArgument();
                return -1;
        }
-       
+
        fo = (PyFloatObject*) (*nb->nb_float) (op);
        if (fo == NULL)
                return -1;
@@ -214,10 +214,10 @@ PyFloat_AsDouble(PyObject *op)
                                "nb_float should return float object");
                return -1;
        }
-       
+
        val = PyFloat_AS_DOUBLE(fo);
        Py_DECREF(fo);
-       
+
        return val;
 }
 
@@ -505,7 +505,7 @@ float_pow(PyObject *v, PyObject *w, PyObject *z)
                else
                        ix = 1.0;
                PyFPE_END_PROTECT(ix)
-               return PyFloat_FromDouble(ix); 
+               return PyFloat_FromDouble(ix);
        }
        if (iv == 0.0) {  /* 0**w is error if w<0, else 1 */
                if (iw < 0.0) {
@@ -537,7 +537,7 @@ static PyObject *
 float_int_div(PyObject *v, PyObject *w)
 {
        PyObject *t, *r;
-       
+
        t = float_divmod(v, w);
        if (t != NULL) {
                r = PyTuple_GET_ITEM(t, 0);
@@ -570,8 +570,10 @@ float_abs(PyFloatObject *v)
 {
        if (v->ob_fval < 0)
                return float_neg(v);
-       else
+       else if (v->ob_fval > 0)
                return float_pos(v);
+       else /* ensure abs(-0) is +0 */
+               return PyFloat_FromDouble(+0.0);
 }
 
 static int