bpo-32030: _PyPathConfig_Init() sets home and program_name (#4673)

_PyPathConfig_Init() now also initialize home and program_name:

* Rename existing _PyPathConfig_Init() to _PyPathConfig_Calculate().
  Add a new _PyPathConfig_Init() function in pathconfig.c which
  handles the _Py_path_config variable and call
  _PyPathConfig_Calculate().
* Add home and program_name fields to _PyPathConfig.home
* _PyPathConfig_Init() now initialize home and program_name
  from main_config
* Py_SetProgramName(), Py_SetPythonHome() and Py_GetPythonHome() now
  calls Py_FatalError() on failure, instead of silently ignoring
  failures.
* config_init_home() now gets directly _Py_path_config.home to only
  get the value set by Py_SetPythonHome(), or NULL if
  Py_SetPythonHome() was not called.
* config_get_program_name() now gets directly
  _Py_path_config.program_name to only get the value set by
  Py_SetProgramName(), or NULL if Py_SetProgramName() was not called.
* pymain_init_python() doesn't call Py_SetProgramName() anymore,
  _PyPathConfig_Init() now always sets the program name
* Call _PyMainInterpreterConfig_Read() in
  pymain_parse_cmdline_envvars_impl() to control the memory allocator
* C API documentation: it's no more safe to call Py_GetProgramName()
  before Py_Initialize().

1 files changed, 6 insertions, 1 deletions

diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 8d71154c56..523397f126 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -804,7 +804,12 @@ _PyMainInterpreterConfig_Read(_PyMainInterpreterConfig *config)
     }
 
     if (config->program_name == NULL) {
-        config->program_name = _PyMem_RawWcsdup(Py_GetProgramName());
+#ifdef MS_WINDOWS
+        const wchar_t *program_name = L"python";
+#else
+        const wchar_t *program_name = L"python3";
+#endif
+        config->program_name = _PyMem_RawWcsdup(program_name);
         if (config->program_name == NULL) {
             return _Py_INIT_NO_MEMORY();
         }