bpo-36763: Add _PyCoreConfig_InitPythonConfig() (GH-13388)

Add new functions to get the Python interpreter behavior:

* _PyPreConfig_InitPythonConfig()
* _PyCoreConfig_InitPythonConfig()

Add new functions to get an isolated configuration:

* _PyPreConfig_InitIsolatedConfig()
* _PyCoreConfig_InitIsolatedConfig()

Replace _PyPreConfig_INIT and _PyCoreConfig_INIT with new functions
_PyPreConfig_Init() and _PyCoreConfig_Init().

_PyCoreConfig: set configure_c_stdio and parse_argv to 0 by default
to behave as Python 3.6 in the default configuration.

_PyCoreConfig_Read() no longer sets coerce_c_locale_warn to 1 if it's
equal to 0. coerce_c_locale_warn must now be set to -1 (ex: using
_PyCoreConfig_InitPythonConfig()) to enable C locale coercion
warning.

Add unit tests for _PyCoreConfig_InitPythonConfig()
and _PyCoreConfig_InitIsolatedConfig().

Changes:

* Rename _PyCoreConfig_GetCoreConfig() to _PyPreConfig_GetCoreConfig()
* Fix core_read_precmdline(): handle parse_argv=0
* Fix _Py_PreInitializeFromCoreConfig(): pass coreconfig.argv
  to _Py_PreInitializeFromPyArgv(), except if parse_argv=0

1 files changed, 20 insertions, 8 deletions

diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index eecb439a11..231706d2ab 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -701,7 +701,8 @@ _Py_PreInitializeFromPyArgv(const _PyPreConfig *src_config, const _PyArgv *args)
         return _Py_INIT_OK();
     }
 
-    _PyPreConfig config = _PyPreConfig_INIT;
+    _PyPreConfig config;
+    _PyPreConfig_Init(&config);
 
     if (src_config) {
         if (_PyPreConfig_Copy(&config, src_config) < 0) {
@@ -752,13 +753,22 @@ _PyInitError
 _Py_PreInitializeFromCoreConfig(const _PyCoreConfig *coreconfig,
                                 const _PyArgv *args)
 {
-    _PyPreConfig config = _PyPreConfig_INIT;
+    _PyPreConfig config;
+    _PyPreConfig_Init(&config);
     if (coreconfig != NULL) {
-        _PyCoreConfig_GetCoreConfig(&config, coreconfig);
+        _PyPreConfig_GetCoreConfig(&config, coreconfig);
+    }
+
+    if (args == NULL && coreconfig != NULL && coreconfig->parse_argv) {
+        _PyArgv config_args = {
+            .use_bytes_argv = 0,
+            .argc = coreconfig->argv.length,
+            .wchar_argv = coreconfig->argv.items};
+        return _Py_PreInitializeFromPyArgv(&config, &config_args);
+    }
+    else {
+        return _Py_PreInitializeFromPyArgv(&config, args);
     }
-    return _Py_PreInitializeFromPyArgv(&config, args);
-    /* No need to clear config:
-       _PyCoreConfig_GetCoreConfig() doesn't allocate memory */
 }
 
 
@@ -829,7 +839,8 @@ _Py_InitializeCore(_PyRuntimeState *runtime,
         return err;
     }
 
-    _PyCoreConfig local_config = _PyCoreConfig_INIT;
+    _PyCoreConfig local_config;
+    _PyCoreConfig_Init(&local_config);
     err = pyinit_coreconfig(runtime, &local_config, src_config, args, interp_p);
     _PyCoreConfig_Clear(&local_config);
     return err;
@@ -1051,7 +1062,8 @@ Py_InitializeEx(int install_sigs)
         return;
     }
 
-    _PyCoreConfig config = _PyCoreConfig_INIT;
+    _PyCoreConfig config;
+    _PyCoreConfig_Init(&config);
     config.install_signal_handlers = install_sigs;
 
     err = _Py_InitializeFromConfig(&config);