BUG/MEDIUM: spoa/python: Fixing references to None

As per https://docs.python.org/3/c-api/none.html, None has to be treated
exactly like other objects for reference counting.
So, when we use it, we need to INCREF and when we are done, DECREF

This patch must be backported as far as 2.0.

(cherry picked from commit bdd034947c4a3a6f8c41af9bf6e62b7a74b4ebbc)
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 20861d6..04b21f1 100644 (file)
--- a/contrib/spoa_server/ps_python.c
+++ b/contrib/spoa_server/ps_python.c
@@ -634,6 +634,7 @@ static int ps_python_exec_message(struct worker *w, void *ref, int nargs, struct
 
                switch (args[i].value.type) {
                case SPOE_DATA_T_NULL:
+                       Py_INCREF(Py_None);
                        value = Py_None;
                        break;
                case SPOE_DATA_T_BOOL:
@@ -722,6 +723,7 @@ static int ps_python_exec_message(struct worker *w, void *ref, int nargs, struct
                        value = PY_BYTES_FROM_STRING_AND_SIZE(args[i].value.u.buffer.str, args[i].value.u.buffer.len);
                        break;
                default:
+                       Py_INCREF(Py_None);
                        value = Py_None;
                        break;
                }
@@ -786,9 +788,7 @@ static int ps_python_exec_message(struct worker *w, void *ref, int nargs, struct
                PyErr_Print();
                return 0;
        }
-       if (result != Py_None) {
-               Py_DECREF(result);
-       }
+       Py_DECREF(result);
 
        return 1;
 }