Charles Waldman writes:

"""
Running "test_extcall" repeatedly results in memory leaks.

One of these can't be fixed (at least not easily!), it happens since
this code:

def saboteur(**kw):
    kw['x'] = locals()
d = {}
saboteur(a=1, **d)

creates a circular reference - d['x']['d']==d

The others are due to some missing decrefs in ceval.c, fixed by the
patch attached below.

Note:  I originally wrote this without the "goto", just adding the
missing decref's where needed.  But I think the goto is justified in
keeping the executable code size of ceval as small as possible.
"""

[I think the circular reference is more like kw['x']['kw'] == kw. --GvR]

diff --git a/Python/ceval.c b/Python/ceval.c
index 989e17f9bfd097e9ab88acd52a15f48924048cae..d0958bdfcf319e6d9b4b9c54f804907fc0a8c079 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1623,8 +1623,7 @@ eval_code2(co, globals, locals,
                            if (!PyDict_Check(kwdict)) {
                                PyErr_SetString(PyExc_TypeError,
                                        "** argument must be a dictionary");
-                               x = NULL;
-                               break;
+                               goto extcall_fail;
                            }
                        }
                        if (flags & 1) {
@@ -1632,39 +1631,34 @@ eval_code2(co, globals, locals,
                            if (!PySequence_Check(stararg)) {
                                PyErr_SetString(PyExc_TypeError,
                                        "* argument must be a sequence");
-                               x = NULL;
-                               break;
+                               goto extcall_fail;
                            }
                            /* Convert abstract sequence to concrete tuple */
                            if (!PyTuple_Check(stararg)) {
                                PyObject *t = NULL;
                                t = PySequence_Tuple(stararg);
                                if (t == NULL) {
-                                   x = NULL;
-                                   break;
+                                   goto extcall_fail;
                                }
                                Py_DECREF(stararg);
                                stararg = t;
                            }
                            nstar = PyTuple_GET_SIZE(stararg);
                            if (nstar < 0) {
-                               x = NULL;
-                               break;
+                               goto extcall_fail;
                            }
                        }
                        if (nk > 0) {
                            if (kwdict == NULL) {
                                kwdict = PyDict_New();
                                if (kwdict == NULL) {
-                                   x = NULL;
-                                   break;
+                                   goto extcall_fail;
                                }
                            }
                            else {
                                    PyObject *d = PyDict_Copy(kwdict);
                                    if (d == NULL) {
-                                           x = NULL;
-                                           break;
+                                           goto extcall_fail;
                                    }
                                    Py_DECREF(kwdict);
                                    kwdict = d;
@@ -1680,7 +1674,7 @@ eval_code2(co, globals, locals,
                                                 PyString_AsString(key));
                                    Py_DECREF(key);
                                    Py_DECREF(value);
-                                   break;
+                                   goto extcall_fail;
                                }
                                err = PyDict_SetItem(kwdict, key, value);
                                Py_DECREF(key);
@@ -1689,7 +1683,11 @@ eval_code2(co, globals, locals,
                                    break;
                            }
                            if (err) {
-                               Py_DECREF(kwdict);
+                             extcall_fail:
+                               Py_XDECREF(kwdict);
+                               Py_XDECREF(stararg);
+                               Py_DECREF(func);
+                               x=NULL;
                                break;
                            }
                        }
@@ -2382,6 +2380,7 @@ PyEval_CallObjectWithKeywords(func, arg, kw)
        if (kw != NULL && !PyDict_Check(kw)) {
                PyErr_SetString(PyExc_TypeError,
                                "keyword list must be a dictionary");
+               Py_DECREF(arg);
                return NULL;
        }