Issue #5829: don't raise OverflowError for complex('1e500'). Backport of r72803.

Lib/test/test_complex.py

@@ -429,6 +429,13 @@ class ComplexTest(unittest.TestCase):
             self.assertEquals(atan2(z1.imag, -1.), atan2(0., -1.))
             self.assertEquals(atan2(z2.imag, -1.), atan2(-0., -1.))
 
+    @unittest.skipUnless(float.__getformat__("double").startswith("IEEE"),
+                         "test requires IEEE 754 doubles")
+    def test_overflow(self):
+        self.assertEqual(complex("1e500"), complex(INF, 0.0))
+        self.assertEqual(complex("-1e500j"), complex(0.0, -INF))
+        self.assertEqual(complex("-1e500+1.8e308j"), complex(-INF, INF))
+
     @unittest.skipUnless(float.__getformat__("double").startswith("IEEE"),
                          "test requires IEEE 754 doubles")
     def test_repr_roundtrip(self):

Misc/NEWS

@@ -12,6 +12,10 @@ What's New in Python 2.7 alpha 1
 Core and Builtins
 -----------------
 
+- Issue #5829: complex("1e500") no longer raises OverflowError.  This
+  makes it consistent with float("1e500") and interpretation of real
+  and imaginary literals.
+
 - Issue #3527: Removed Py_WIN_WIDE_FILENAMES which is not used any more.
 
 - __instancecheck__ and __subclasscheck__ are now completely ignored on classic

Objects/complexobject.c

@@ -989,8 +989,6 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
 	z = PyOS_ascii_strtod(s, &end);
 	if (end == s && errno == ENOMEM)
 		return PyErr_NoMemory();
-	if (errno == ERANGE && fabs(z) >= 1.0)
-		goto overflow;
 
 	if (end != s) {
 		/* all 4 forms starting with <float> land here */
@@ -1002,8 +1000,6 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
 			y = PyOS_ascii_strtod(s, &end);
 			if (end == s && errno == ENOMEM)
 				return PyErr_NoMemory();
-			if (errno == ERANGE && fabs(y) >= 1.0)
-				goto overflow;
 			if (end != s)
 				/* <float><signed-float>j */
 				s = end;
@@ -1063,11 +1059,6 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
 	PyErr_SetString(PyExc_ValueError,
 			"complex() arg is a malformed string");
 	return NULL;
-
-  overflow:
-	PyErr_SetString(PyExc_OverflowError,
-			"complex() arg overflow");
-	return NULL;
 }
 
 static PyObject *