bpo-38304: Add PyConfig.struct_size (GH-16451)

Add a new struct_size field to PyPreConfig and PyConfig structures to
allow to modify these structures in the future without breaking the
backward compatibility.

* Replace private _config_version field with public struct_size field
  in PyPreConfig and PyConfig.
* Public PyPreConfig_InitIsolatedConfig() and
  PyPreConfig_InitPythonConfig()
  return type becomes PyStatus, instead of void.
* Internal _PyConfig_InitCompatConfig(),
  _PyPreConfig_InitCompatConfig(), _PyPreConfig_InitFromConfig(),
  _PyPreConfig_InitFromPreConfig() return type becomes PyStatus,
  instead of void.
* Remove _Py_CONFIG_VERSION
* Update the Initialization Configuration documentation.

1 files changed, 7 insertions, 1 deletions

diff --git a/Python/pystate.c b/Python/pystate.c
index 7dd8b7f..0f0cb22 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -60,7 +60,12 @@ _PyRuntimeState_Init_impl(_PyRuntimeState *runtime)
 
     _PyGC_Initialize(&runtime->gc);
     _PyEval_Initialize(&runtime->ceval);
-    PyPreConfig_InitPythonConfig(&runtime->preconfig);
+
+    runtime->preconfig.struct_size = sizeof(PyPreConfig);
+    PyStatus status = PyPreConfig_InitPythonConfig(&runtime->preconfig);
+    if (_PyStatus_EXCEPTION(status)) {
+        return status;
+    }
 
     runtime->gilstate.check_enabled = 1;
 
@@ -204,6 +209,7 @@ PyInterpreterState_New(void)
     memset(interp, 0, sizeof(*interp));
     interp->id_refcount = -1;
 
+    interp->config.struct_size = sizeof(PyConfig);
     PyStatus status = PyConfig_InitPythonConfig(&interp->config);
     if (_PyStatus_EXCEPTION(status)) {
         /* Don't report status to caller: PyConfig_InitPythonConfig()