Issue #8748: Fix two issues with comparisons between complex and integer

objects.  (1) The comparison could incorrectly return True in some cases
(2**53+1 == complex(2**53) == 2**53), breaking transivity of equality.
(2) The comparison raised an OverflowError for large integers, leading
to unpredictable exceptions when combining integers and complex objects
in sets or dicts.

Patch by Meador Inge.

1 files changed, 44 insertions, 8 deletions

diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index ec26e0a700..9e1e217856 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -620,22 +620,58 @@ static PyObject *
 complex_richcompare(PyObject *v, PyObject *w, int op)
 {
     PyObject *res;
-    Py_complex i, j;
-    TO_COMPLEX(v, i);
-    TO_COMPLEX(w, j);
+    Py_complex i;
+    int equal;
 
     if (op != Py_EQ && op != Py_NE) {
-        Py_INCREF(Py_NotImplemented);
-        return Py_NotImplemented;
+        goto Unimplemented;
     }
 
-    if ((i.real == j.real && i.imag == j.imag) == (op == Py_EQ))
-        res = Py_True;
+    assert(PyComplex_Check(v));
+    TO_COMPLEX(v, i);
+
+    if (PyLong_Check(w)) {
+        /* Check for 0.0 imaginary part first to avoid the rich
+         * comparison when possible.
+         */
+        if (i.imag == 0.0) {
+            PyObject *j, *sub_res;
+            j = PyFloat_FromDouble(i.real);
+            if (j == NULL)
+                return NULL;
+
+            sub_res = PyObject_RichCompare(j, w, op);
+            Py_DECREF(j);
+            return sub_res;
+        }
+        else {
+            equal = 0;
+        }
+    }
+    else if (PyFloat_Check(w)) {
+        equal = (i.real == PyFloat_AsDouble(w) && i.imag == 0.0);
+    }
+    else if (PyComplex_Check(w)) {
+        Py_complex j;
+
+        TO_COMPLEX(w, j);
+        equal = (i.real == j.real && i.imag == j.imag);
+    }
+    else {
+        goto Unimplemented;
+    }
+
+    if (equal == (op == Py_EQ))
+         res = Py_True;
     else
-        res = Py_False;
+         res = Py_False;
 
     Py_INCREF(res);
     return res;
+
+Unimplemented:
+    Py_INCREF(Py_NotImplemented);
+    return Py_NotImplemented;
 }
 
 static PyObject *