Re-implement the 'warnings' module in C. This allows for usage of the

'warnings' code in places where it was previously not possible (e.g., the
parser). It could also potentially lead to a speed-up in interpreter start-up
if the C version of the code (_warnings) is imported over the use of the
Python version in key places.

Closes issue #1631171.

1 files changed, 15 insertions, 60 deletions

diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 6cc9f6df5d..a9b7f81ff7 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -83,38 +83,12 @@ int Py_IgnoreEnvironmentFlag; /* e.g. PYTHONPATH, PYTHONHOME */
   true divisions (which they will be in 2.3). */
 int _Py_QnewFlag = 0;
 
-/* Reference to 'warnings' module, to avoid importing it
-   on the fly when the import lock may be held.  See 683658/771097
-*/
-static PyObject *warnings_module = NULL;
-
-/* Returns a borrowed reference to the 'warnings' module, or NULL.
-   If the module is returned, it is guaranteed to have been obtained
-   without acquiring the import lock
-*/
-PyObject *PyModule_GetWarningsModule(void)
-{
-	PyObject *typ, *val, *tb;
-	PyObject *all_modules;
-	/* If we managed to get the module at init time, just use it */
-	if (warnings_module)
-		return warnings_module;
-	/* If it wasn't available at init time, it may be available
-	   now in sys.modules (common scenario is frozen apps: import
-	   at init time fails, but the frozen init code sets up sys.path
-	   correctly, then does an implicit import of warnings for us
-	*/
-	/* Save and restore any exceptions */
-	PyErr_Fetch(&typ, &val, &tb);
-
-	all_modules = PySys_GetObject("modules");
-	if (all_modules) {
-		warnings_module = PyDict_GetItemString(all_modules, "warnings");
-		/* We keep a ref in the global */
-		Py_XINCREF(warnings_module);
-	}
-	PyErr_Restore(typ, val, tb);
-	return warnings_module;
+/* PyModule_GetWarningsModule is no longer necessary as of 2.6
+since _warnings is builtin.  This API should not be used. */
+PyObject *
+PyModule_GetWarningsModule(void)
+{
+	return PyImport_ImportModule("warnings");
 }
 
 static int initialized = 0;
@@ -244,6 +218,15 @@ Py_InitializeEx(int install_sigs)
 
 	if (install_sigs)
 		initsigs(); /* Signal handling stuff, including initintr() */
+		
+    /* Initialize warnings. */
+    _PyWarnings_Init();
+    if (PySys_HasWarnOptions()) {
+        PyObject *warnings_module = PyImport_ImportModule("warnings");
+        if (!warnings_module)
+            PyErr_Clear();
+        Py_XDECREF(warnings_module);
+    }
 
 	initmain(); /* Module __main__ */
 	if (!Py_NoSiteFlag)
@@ -254,30 +237,6 @@ Py_InitializeEx(int install_sigs)
 	_PyGILState_Init(interp, tstate);
 #endif /* WITH_THREAD */
 
-	warnings_module = PyImport_ImportModule("warnings");
-	if (!warnings_module) {
-		PyErr_Clear();
-	}
-	else {
-		PyObject *o;
-		char *action[8];
-
-		if (Py_BytesWarningFlag > 1)
-			*action = "error";
-		else if (Py_BytesWarningFlag)
-			*action = "default";
-		else
-			*action = "ignore";
-
-		o = PyObject_CallMethod(warnings_module,
-					"simplefilter", "sO",
-					*action, PyExc_BytesWarning);
-		if (o == NULL)
-			Py_FatalError("Py_Initialize: can't initialize"
-				      "warning filter for BytesWarning.");
-		Py_DECREF(o);
-        }
-
 #if defined(Py_USING_UNICODE) && defined(HAVE_LANGINFO_H) && defined(CODESET)
 	/* On Unix, set the file system encoding according to the
 	   user's preference, if the CODESET names a well-known
@@ -397,10 +356,6 @@ Py_Finalize(void)
 	/* Disable signal handling */
 	PyOS_FiniInterrupts();
 
-	/* drop module references we saved */
-	Py_XDECREF(warnings_module);
-	warnings_module = NULL;
-
 	/* Clear type lookup cache */
 	PyType_ClearCache();