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, 35 insertions, 9 deletions

diff --git a/Include/pylifecycle.h b/Include/pylifecycle.h
index f7286f3764..a75b77cc73 100644
--- a/Include/pylifecycle.h
+++ b/Include/pylifecycle.h
@@ -20,18 +20,44 @@ PyAPI_FUNC(wchar_t *) Py_GetPythonHome(void);
 PyAPI_FUNC(int) Py_SetStandardStreamEncoding(const char *encoding,
                                              const char *errors);
 
+typedef struct {
+    const char *prefix;
+    const char *msg;
+    int user_err;
+} _PyInitError;
+
+/* Almost all errors causing Python initialization to fail */
+#ifdef _MSC_VER
+   /* Visual Studio 2015 doesn't implement C99 __func__ in C */
+#  define _Py_INIT_GET_FUNC() __FUNCTION__
+#else
+#  define _Py_INIT_GET_FUNC() __func__
+#endif
+
+#define _Py_INIT_OK() \
+    (_PyInitError){.prefix = NULL, .msg = NULL, .user_err = 0}
+#define _Py_INIT_ERR(MSG) \
+    (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 0}
+/* Error that can be fixed by the user like invalid input parameter.
+   Don't abort() the process on such error. */
+#define _Py_INIT_USER_ERR(MSG) \
+    (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 1}
+#define _Py_INIT_FAILED(err) \
+    (err.msg != NULL)
+
 /* PEP 432 Multi-phase initialization API (Private while provisional!) */
-PyAPI_FUNC(void) _Py_InitializeCore(const _PyCoreConfig *);
+PyAPI_FUNC(_PyInitError) _Py_InitializeCore(const _PyCoreConfig *);
 PyAPI_FUNC(int) _Py_IsCoreInitialized(void);
-PyAPI_FUNC(int) _Py_ReadMainInterpreterConfig(_PyMainInterpreterConfig *);
-PyAPI_FUNC(int) _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *);
+PyAPI_FUNC(_PyInitError) _Py_ReadMainInterpreterConfig(_PyMainInterpreterConfig *);
+PyAPI_FUNC(_PyInitError) _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *);
 #endif
 
 /* Initialization and finalization */
 PyAPI_FUNC(void) Py_Initialize(void);
 PyAPI_FUNC(void) Py_InitializeEx(int);
 #ifndef Py_LIMITED_API
-PyAPI_FUNC(void) _Py_InitializeEx_Private(int, int);
+PyAPI_FUNC(_PyInitError) _Py_InitializeEx_Private(int, int);
+PyAPI_FUNC(void) _Py_FatalInitError(_PyInitError err) _Py_NO_RETURN;
 #endif
 PyAPI_FUNC(void) Py_Finalize(void);
 PyAPI_FUNC(int) Py_FinalizeEx(void);
@@ -50,7 +76,7 @@ PyAPI_FUNC(void) _Py_PyAtExit(void (*func)(void));
 #endif
 PyAPI_FUNC(int) Py_AtExit(void (*func)(void));
 
-PyAPI_FUNC(void) Py_Exit(int);
+PyAPI_FUNC(void) Py_Exit(int) _Py_NO_RETURN;
 
 /* Restore signals that the interpreter has called SIG_IGN on to SIG_DFL. */
 #ifndef Py_LIMITED_API
@@ -86,15 +112,15 @@ PyAPI_FUNC(const char *) _Py_gitversion(void);
 /* Internal -- various one-time initializations */
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject *) _PyBuiltin_Init(void);
-PyAPI_FUNC(PyObject *) _PySys_BeginInit(void);
+PyAPI_FUNC(_PyInitError) _PySys_BeginInit(PyObject **sysmod);
 PyAPI_FUNC(int) _PySys_EndInit(PyObject *sysdict);
-PyAPI_FUNC(void) _PyImport_Init(void);
+PyAPI_FUNC(_PyInitError) _PyImport_Init(void);
 PyAPI_FUNC(void) _PyExc_Init(PyObject * bltinmod);
-PyAPI_FUNC(void) _PyImportHooks_Init(void);
+PyAPI_FUNC(_PyInitError) _PyImportHooks_Init(void);
 PyAPI_FUNC(int) _PyFrame_Init(void);
 PyAPI_FUNC(int) _PyFloat_Init(void);
 PyAPI_FUNC(int) PyByteArray_Init(void);
-PyAPI_FUNC(void) _Py_HashRandomization_Init(_PyCoreConfig *core_config);
+PyAPI_FUNC(_PyInitError) _Py_HashRandomization_Init(_PyCoreConfig *core_config);
 #endif
 
 /* Various internal finalizers */