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, 8 insertions, 1 deletions

diff --git a/Modules/main.c b/Modules/main.c
index fdc7e0d..ef6c66a 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -53,13 +53,20 @@ pymain_init(const _PyArgv *args)
 #endif
 
     PyPreConfig preconfig;
-    PyPreConfig_InitPythonConfig(&preconfig);
+    preconfig.struct_size = sizeof(PyPreConfig);
+
+    status = PyPreConfig_InitPythonConfig(&preconfig);
+    if (_PyStatus_EXCEPTION(status)) {
+        return status;
+    }
+
     status = _Py_PreInitializeFromPyArgv(&preconfig, args);
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
 
     PyConfig config;
+    config.struct_size = sizeof(PyConfig);
     status = PyConfig_InitPythonConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
         goto done;