bpo-36763: Use _PyCoreConfig_InitPythonConfig() (GH-13398)

_PyPreConfig_InitPythonConfig() and _PyCoreConfig_InitPythonConfig()
no longer inherit their values from global configuration variables.

Changes:

* _PyPreCmdline_Read() now ignores -X dev and PYTHONDEVMODE
  if dev_mode is already set.
* Inline _PyPreConfig_INIT macro into _PyPreConfig_Init() function.
* Inline _PyCoreConfig_INIT macro into _PyCoreConfig_Init() function.
* Replace _PyCoreConfig_Init() with _PyCoreConfig_InitPythonConfig()
  in most tests of _testembed.c.
* Replace _PyCoreConfig_Init() with _PyCoreConfig_InitIsolatedConfig()
  in _freeze_importlib.c.
* Move some initialization functions from the internal
  to the private API.

3 files changed, 78 insertions, 24 deletions

diff --git a/Python/coreconfig.c b/Python/coreconfig.c
index fd45726..3678d12 100644
--- a/Python/coreconfig.c
+++ b/Python/coreconfig.c
@@ -551,14 +551,69 @@ _PyCoreConfig_Clear(_PyCoreConfig *config)
 void
 _PyCoreConfig_Init(_PyCoreConfig *config)
 {
-    *config = _PyCoreConfig_INIT;
+    memset(config, 0, sizeof(*config));
+
+    config->_config_version = _Py_CONFIG_VERSION;
+    config->isolated = -1;
+    config->use_environment = -1;
+    config->dev_mode = -1;
+    config->install_signal_handlers = 1;
+    config->use_hash_seed = -1;
+    config->faulthandler = -1;
+    config->tracemalloc = -1;
+    config->use_module_search_paths = 0;
+    config->parse_argv = 0;
+    config->site_import = -1;
+    config->bytes_warning = -1;
+    config->inspect = -1;
+    config->interactive = -1;
+    config->optimization_level = -1;
+    config->parser_debug= -1;
+    config->write_bytecode = -1;
+    config->verbose = -1;
+    config->quiet = -1;
+    config->user_site_directory = -1;
+    config->configure_c_stdio = 0;
+    config->buffered_stdio = -1;
+    config->_install_importlib = 1;
+    config->check_hash_pycs_mode = NULL;
+    config->pathconfig_warnings = -1;
+    config->_init_main = 1;
+#ifdef MS_WINDOWS
+    config->legacy_windows_stdio = -1;
+#endif
+}
+
+
+static void
+_PyCoreConfig_InitDefaults(_PyCoreConfig *config)
+{
+    _PyCoreConfig_Init(config);
+
+    config->isolated = 0;
+    config->use_environment = 1;
+    config->site_import = 1;
+    config->bytes_warning = 0;
+    config->inspect = 0;
+    config->interactive = 0;
+    config->optimization_level = 0;
+    config->parser_debug= 0;
+    config->write_bytecode = 1;
+    config->verbose = 0;
+    config->quiet = 0;
+    config->user_site_directory = 1;
+    config->buffered_stdio = 1;
+    config->pathconfig_warnings = 1;
+#ifdef MS_WINDOWS
+    config->legacy_windows_stdio = 0;
+#endif
 }
 
 
 _PyInitError
 _PyCoreConfig_InitPythonConfig(_PyCoreConfig *config)
 {
-    _PyCoreConfig_Init(config);
+    _PyCoreConfig_InitDefaults(config);
 
     config->configure_c_stdio = 1;
     config->parse_argv = 1;
@@ -570,30 +625,16 @@ _PyCoreConfig_InitPythonConfig(_PyCoreConfig *config)
 _PyInitError
 _PyCoreConfig_InitIsolatedConfig(_PyCoreConfig *config)
 {
-    _PyCoreConfig_Init(config);
+    _PyCoreConfig_InitDefaults(config);
 
-    /* set to 1 */
     config->isolated = 1;
-    config->site_import = 1;
-    config->write_bytecode = 1;
-    config->buffered_stdio = 1;
-
-    /* set to 0 */
     config->use_environment = 0;
+    config->user_site_directory = 0;
     config->dev_mode = 0;
     config->install_signal_handlers = 0;
     config->use_hash_seed = 0;
     config->faulthandler = 0;
     config->tracemalloc = 0;
-    config->bytes_warning = 0;
-    config->inspect = 0;
-    config->interactive = 0;
-    config->optimization_level = 0;
-    config->parser_debug = 0;
-    config->verbose = 0;
-    config->quiet = 0;
-    config->user_site_directory = 0;
-    config->configure_c_stdio = 0;
     config->pathconfig_warnings = 0;
 #ifdef MS_WINDOWS
     config->legacy_windows_stdio = 0;
diff --git a/Python/frozenmain.c b/Python/frozenmain.c
index 7b232bb..a51fb58 100644
--- a/Python/frozenmain.c
+++ b/Python/frozenmain.c
@@ -40,7 +40,7 @@ Py_FrozenMain(int argc, char **argv)
     }
 
     _PyCoreConfig config;
-    _PyCoreConfig_Init(&config);
+    _PyCoreConfig_InitPythonConfig(&config);
     config.pathconfig_warnings = 0;   /* Suppress errors from getpath.c */
 
     if ((p = Py_GETENV("PYTHONINSPECT")) && *p != '\0')
diff --git a/Python/preconfig.c b/Python/preconfig.c
index b7bcfeb..0f4bd8e 100644
--- a/Python/preconfig.c
+++ b/Python/preconfig.c
@@ -241,8 +241,9 @@ _PyPreCmdline_Read(_PyPreCmdline *cmdline,
     }
 
     /* dev_mode */
-    if ((cmdline && _Py_get_xoption(&cmdline->xoptions, L"dev"))
-        || _Py_GetEnv(cmdline->use_environment, "PYTHONDEVMODE"))
+    if ((cmdline->dev_mode < 0)
+        && (_Py_get_xoption(&cmdline->xoptions, L"dev")
+            || _Py_GetEnv(cmdline->use_environment, "PYTHONDEVMODE")))
     {
         cmdline->dev_mode = 1;
     }
@@ -260,10 +261,22 @@ _PyPreCmdline_Read(_PyPreCmdline *cmdline,
 
 /* --- _PyPreConfig ----------------------------------------------- */
 
+
 void
 _PyPreConfig_Init(_PyPreConfig *config)
 {
-    *config = _PyPreConfig_INIT;
+    memset(config, 0, sizeof(*config));
+
+    config->_config_version = _Py_CONFIG_VERSION;
+    config->isolated = -1;
+    config->use_environment = -1;
+    config->configure_locale = 1;
+    config->utf8_mode = -2;
+    config->dev_mode = -1;
+    config->allocator = PYMEM_ALLOCATOR_NOT_SET;
+#ifdef MS_WINDOWS
+    config->legacy_windows_fs_encoding = -1;
+#endif
 }
 
 
@@ -289,11 +302,11 @@ _PyPreConfig_InitIsolatedConfig(_PyPreConfig *config)
     config->configure_locale = 0;
     config->isolated = 1;
     config->use_environment = 0;
+    config->utf8_mode = 0;
+    config->dev_mode = 0;
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = 0;
 #endif
-    config->utf8_mode = 0;
-    config->dev_mode = 0;
 }