BUG/MEDIUM: spoa/python: Fixing PyObject_Call positional arguments

As per https://docs.python.org/3/c-api/object.html#c.PyObject_Call,
positional arguments should be an empty tuple when not used.
Previously the code had a dictionary instead of tuple. This commit is to
fix it and use tuple to avoid unexpected consequences

This patch must be backported as far as 2.0.

(cherry picked from commit 042f697a0fce0255b569786d29e929a4a41cbc46)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/contrib/spoa_server/ps_python.c b/contrib/spoa_server/ps_python.c
index f2ddc16..20861d6 100644 (file)
--- a/contrib/spoa_server/ps_python.c
+++ b/contrib/spoa_server/ps_python.c
@@ -43,7 +43,7 @@ static PyObject *module_ipaddress;
 static PyObject *ipv4_address;
 static PyObject *ipv6_address;
 static PyObject *spoa_error;
-static PyObject *empty_array;
+static PyObject *empty_tuple;
 static struct worker *worker;
 
 static int ps_python_start_worker(struct worker *w);
@@ -522,8 +522,8 @@ static int ps_python_start_worker(struct worker *w)
                return 0;
        }
 
-       empty_array = PyDict_New();
-       if (empty_array == NULL) {
+       empty_tuple = PyTuple_New(0);
+       if (empty_tuple == NULL) {
                PyErr_Print();
                return 0;
        }
@@ -710,7 +710,7 @@ static int ps_python_exec_message(struct worker *w, void *ref, int nargs, struct
                                PyErr_Print();
                                return 0;
                        }
-                       value = PyObject_Call(func, empty_array, ip_dict);
+                       value = PyObject_Call(func, empty_tuple, ip_dict);
                        Py_DECREF(func);
                        Py_DECREF(ip_dict);
                        break;
@@ -780,7 +780,7 @@ static int ps_python_exec_message(struct worker *w, void *ref, int nargs, struct
                return 0;
        }
 
-       result = PyObject_Call(python_ref, empty_array, fkw);
+       result = PyObject_Call(python_ref, empty_tuple, fkw);
        Py_DECREF(fkw);
        if (result == NULL) {
                PyErr_Print();