bpo-32030: Split Py_Main() into subfunctions (#4399)

* Don't use "Python runtime" anymore to parse command line options or
  to get environment variables: pymain_init() is now a strict
  separation.
* Use an error message rather than "crashing" directly with
  Py_FatalError(). Limit the number of calls to Py_FatalError(). It
  prepares the code to handle errors more nicely later.
* Warnings options (-W, PYTHONWARNINGS) and "XOptions" (-X) are now
  only added to the sys module once Python core is properly
  initialized.
* _PyMain is now the well identified owner of some important strings
  like: warnings options, XOptions, and the "program name". The
  program name string is now properly freed at exit.
  pymain_free() is now responsible to free the "command" string.
* Rename most methods in Modules/main.c to use a "pymain_" prefix to
  avoid conflits and ease debug.
* Replace _Py_CommandLineDetails_INIT with memset(0)
* Reorder a lot of code to fix the initialization ordering. For
  example, initializing standard streams now comes before parsing
  PYTHONWARNINGS.
* Py_Main() now handles errors when adding warnings options and
  XOptions.
* Add _PyMem_GetDefaultRawAllocator() private function.
* Cleanup _PyMem_Initialize(): remove useless global constants: move
  them into _PyMem_Initialize().
* Call _PyRuntime_Initialize() as soon as possible:
  _PyRuntime_Initialize() now returns an error message on failure.
* Add _PyInitError structure and following macros:

  * _Py_INIT_OK()
  * _Py_INIT_ERR(msg)
  * _Py_INIT_USER_ERR(msg): "user" error, don't abort() in that case
  * _Py_INIT_FAILED(err)

1 files changed, 20 insertions, 13 deletions

diff --git a/Python/import.c b/Python/import.c
index 950c872ccb..fe60844ef1 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -42,19 +42,23 @@ module _imp
 
 /* Initialize things */
 
-void
+_PyInitError
 _PyImport_Init(void)
 {
     PyInterpreterState *interp = PyThreadState_Get()->interp;
     initstr = PyUnicode_InternFromString("__init__");
-    if (initstr == NULL)
-        Py_FatalError("Can't initialize import variables");
+    if (initstr == NULL) {
+        return _Py_INIT_ERR("Can't initialize import variables");
+    }
+
     interp->builtins_copy = PyDict_Copy(interp->builtins);
-    if (interp->builtins_copy == NULL)
-        Py_FatalError("Can't backup builtins dict");
+    if (interp->builtins_copy == NULL) {
+        return _Py_INIT_ERR("Can't backup builtins dict");
+    }
+    return _Py_INIT_OK();
 }
 
-void
+_PyInitError
 _PyImportHooks_Init(void)
 {
     PyObject *v, *path_hooks = NULL;
@@ -80,15 +84,18 @@ _PyImportHooks_Init(void)
         goto error;
     err = PySys_SetObject("path_hooks", path_hooks);
     if (err) {
-  error:
-    PyErr_Print();
-    Py_FatalError("initializing sys.meta_path, sys.path_hooks, "
-                  "or path_importer_cache failed");
+        goto error;
     }
     Py_DECREF(path_hooks);
+    return _Py_INIT_OK();
+
+  error:
+    PyErr_Print();
+    return _Py_INIT_ERR("initializing sys.meta_path, sys.path_hooks, "
+                        "or path_importer_cache failed");
 }
 
-void
+_PyInitError
 _PyImportZip_Init(void)
 {
     PyObject *path_hooks, *zimpimport;
@@ -133,11 +140,11 @@ _PyImportZip_Init(void)
         }
     }
 
-    return;
+    return _Py_INIT_OK();
 
   error:
     PyErr_Print();
-    Py_FatalError("initializing zipimport failed");
+    return _Py_INIT_ERR("initializing zipimport failed");
 }
 
 /* Locking primitives to prevent parallel imports of the same module