bpo-32030: Enhance Py_Main() (#4412)

Parse more env vars in Py_Main():

* Add more options to _PyCoreConfig:

  * faulthandler
  * tracemalloc
  * importtime

* Move code to parse environment variables from _Py_InitializeCore()
  to Py_Main(). This change fixes a regression from Python 3.6:
  PYTHONUNBUFFERED is now read before calling pymain_init_stdio().
* _PyFaulthandler_Init() and _PyTraceMalloc_Init() now take an
  argument to decide if the module has to be enabled at startup.
* tracemalloc_start() is now responsible to check the maximum number
  of frames.

Other changes:

* Cleanup Py_Main():

  * Rename some pymain_xxx() subfunctions
  * Add pymain_run_python() subfunction

* Cleanup Py_NewInterpreter()
* _PyInterpreterState_Enable() now reports failure
* init_hash_secret() now considers pyurandom() failure as an "user
  error": don't fail with abort().
* pymain_optlist_append() and pymain_strdup() now sets err on memory
  allocation failure.

1 files changed, 6 insertions, 25 deletions

diff --git a/Python/import.c b/Python/import.c
index fe60844..fef6398 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -1675,10 +1675,9 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals,
     }
     else {
         /* 1 -- true, 0 -- false, -1 -- not initialized */
-        static int ximporttime = -1;
+        int importtime = interp->core_config.importtime;
         static int import_level;
         static _PyTime_t accumulated;
-        _Py_IDENTIFIER(importtime);
 
         _PyTime_t t1 = 0, accumulated_copy = accumulated;
 
@@ -1687,32 +1686,14 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals,
          * Anyway, importlib._find_and_load is much slower than
          * _PyDict_GetItemIdWithError().
          */
-        if (ximporttime < 0) {
-            const char *envoption = Py_GETENV("PYTHONPROFILEIMPORTTIME");
-            if (envoption != NULL && *envoption != '\0') {
-                ximporttime = 1;
-            }
-            else {
-                PyObject *xoptions = PySys_GetXOptions();
-                PyObject *value = NULL;
-                if (xoptions) {
-                    value = _PyDict_GetItemIdWithError(
-                        xoptions, &PyId_importtime);
-                }
-                if (value == NULL && PyErr_Occurred()) {
-                    goto error;
-                }
-                if (value != NULL || Py_IsInitialized()) {
-                    ximporttime = (value == Py_True);
-                }
-            }
-            if (ximporttime > 0) {
+        if (importtime) {
+            static int header = 1;
+            if (header) {
                 fputs("import time: self [us] | cumulative | imported package\n",
                       stderr);
+                header = 0;
             }
-        }
 
-        if (ximporttime > 0) {
             import_level++;
             t1 = _PyTime_GetPerfCounter();
             accumulated = 0;
@@ -1731,7 +1712,7 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals,
             PyDTrace_IMPORT_FIND_LOAD_DONE(PyUnicode_AsUTF8(abs_name),
                                            mod != NULL);
 
-        if (ximporttime > 0) {
+        if (importtime) {
             _PyTime_t cum = _PyTime_GetPerfCounter() - t1;
 
             import_level--;