bpo-45292: [PEP 654] add the ExceptionGroup and BaseExceptionGroup classes

Doc/data/stable_abi.dat

@@ -189,6 +189,7 @@ var,PyExc_ArithmeticError,3.2,
 var,PyExc_AssertionError,3.2,
 var,PyExc_AttributeError,3.2,
 var,PyExc_BaseException,3.2,
+var,PyExc_BaseExceptionGroup,3.11,
 var,PyExc_BlockingIOError,3.7,
 var,PyExc_BrokenPipeError,3.7,
 var,PyExc_BufferError,3.2,

Include/cpython/pyerrors.h

@@ -14,6 +14,12 @@ typedef struct {
     PyException_HEAD
 } PyBaseExceptionObject;
 
+typedef struct {
+    PyException_HEAD
+    PyObject *msg;
+    PyObject *excs;
+} PyBaseExceptionGroupObject;
+
 typedef struct {
     PyException_HEAD
     PyObject *msg;

Include/internal/pycore_interp.h

@@ -205,6 +205,8 @@ struct _Py_exc_state {
     PyObject *errnomap;
     PyBaseExceptionObject *memerrors_freelist;
     int memerrors_numfree;
+    // The ExceptionGroup type
+    PyObject *PyExc_ExceptionGroup;
 };
 
 

Include/internal/pycore_pylifecycle.h

@@ -93,6 +93,7 @@ extern void _PyAsyncGen_Fini(PyInterpreterState *interp);
 extern int _PySignal_Init(int install_signal_handlers);
 extern void _PySignal_Fini(void);
 
+extern void _PyExc_ClearExceptionGroupType(PyInterpreterState *interp);
 extern void _PyExc_Fini(PyInterpreterState *interp);
 extern void _PyImport_Fini(void);
 extern void _PyImport_Fini2(void);

Include/pyerrors.h

@@ -60,11 +60,14 @@ PyAPI_FUNC(const char *) PyExceptionClass_Name(PyObject *);
 
 #define PyExceptionInstance_Class(x) ((PyObject*)Py_TYPE(x))
 
+#define _PyBaseExceptionGroup_Check(x)                   \
+    PyObject_TypeCheck(x, (PyTypeObject *)PyExc_BaseExceptionGroup)
 
 /* Predefined exceptions */
 
 PyAPI_DATA(PyObject *) PyExc_BaseException;
 PyAPI_DATA(PyObject *) PyExc_Exception;
+PyAPI_DATA(PyObject *) PyExc_BaseExceptionGroup;
 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03050000
 PyAPI_DATA(PyObject *) PyExc_StopAsyncIteration;
 #endif

Lib/test/exception_hierarchy.txt

@@ -2,7 +2,9 @@ BaseException
  ├── SystemExit
  ├── KeyboardInterrupt
  ├── GeneratorExit
+ ├── BaseExceptionGroup
  └── Exception
+      ├── ExceptionGroup [BaseExceptionGroup]
       ├── StopIteration
       ├── StopAsyncIteration
       ├── ArithmeticError

Lib/test/test_descr.py

@@ -4032,7 +4032,11 @@ def test_builtin_bases(self):
         for tp in builtin_types:
             object.__getattribute__(tp, "__bases__")
             if tp is not object:
-                self.assertEqual(len(tp.__bases__), 1, tp)
+                if tp is ExceptionGroup:
+                    num_bases = 2
+                else:
+                    num_bases = 1
+                self.assertEqual(len(tp.__bases__), num_bases, tp)
 
         class L(list):
             pass

Lib/test/test_doctest.py

@@ -668,7 +668,7 @@ def non_Python_modules(): r"""
 
     >>> import builtins
     >>> tests = doctest.DocTestFinder().find(builtins)
-    >>> 820 < len(tests) < 840 # approximate number of objects with docstrings
+    >>> 825 < len(tests) < 845 # approximate number of objects with docstrings
     True
     >>> real_tests = [t for t in tests if len(t.examples) > 0]
     >>> len(real_tests) # objects that actually have doctests