From: Guido van Rossum <guido@python.org>
Date: Sun, 2 Mar 2003 13:51:47 +0000 (+0000)
Subject: Fix from Greg Chapman from SF bug #695651: a complex subclass
X-Git-Tag: v2.3c1~1621
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4eadfa2b2eeca190546261149cbf1607488dea0a;p=python

Fix from Greg Chapman from SF bug #695651: a complex subclass
constructor, when passed a single complex argument, returns the
argument unchanged.  This should be done only for the complex base
class; a complex subclass should of course cast the value to the
subclass in this case.

The fix also revealed a segfault in complex_getnewargs(): the argument
for the Py_BuildValue() format code "D" is the *address* of a
Py_complex struct, not the value.  (This corroborated by the API
documentation.)

I expect this needs to be backported to 2.2.3.
---

diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index 201da4d3fe..a346ac25a6 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -642,7 +642,7 @@ complex_conjugate(PyObject *self)
 static PyObject *
 complex_getnewargs(PyComplexObject *v)
 {
-	return Py_BuildValue("(D)", v->cval);
+	return Py_BuildValue("(D)", &v->cval);
 }
 
 static PyMethodDef complex_methods[] = {
@@ -832,7 +832,8 @@ complex_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 		return NULL;
 
 	/* Special-case for single argumet that is already complex */
-	if (PyComplex_CheckExact(r) && i == NULL) {
+	if (PyComplex_CheckExact(r) && i == NULL &&
+	    type == &PyComplex_Type) {
 		/* Note that we can't know whether it's safe to return
 		   a complex *subclass* instance as-is, hence the restriction
 		   to exact complexes here.  */