bpo-45711: Do not push/pop traceback on stack as part of exc_info

Doc/library/dis.rst

@@ -474,13 +474,15 @@ the original TOS1.
 .. opcode:: END_ASYNC_FOR
 
    Terminates an :keyword:`async for` loop.  Handles an exception raised
-   when awaiting a next item.  If TOS is :exc:`StopAsyncIteration` pop 7
+   when awaiting a next item.  If TOS is :exc:`StopAsyncIteration` pop 5
    values from the stack and restore the exception state using the second
-   three of them.  Otherwise re-raise the exception using the three values
+   two of them.  Otherwise re-raise the exception using the two values
    from the stack.  An exception handler block is removed from the block stack.
 
    .. versionadded:: 3.8
 
+    .. versionchanged:: 3.11
+       Exception representation on the stack now consist of two, not three, items.
 
 .. opcode:: BEFORE_ASYNC_WITH
 
@@ -561,8 +563,10 @@ iterations of the loop.
 
 .. opcode:: POP_EXCEPT
 
-   Pops three values from the stack, which are used to restore the exception state.
+   Pops two values from the stack, which are used to restore the exception state.
 
+    .. versionchanged:: 3.11
+       Exception representation on the stack now consist of two, not three, items.
 
 .. opcode:: RERAISE
 
@@ -572,27 +576,30 @@ iterations of the loop.
 
     .. versionadded:: 3.9
 
+    .. versionchanged:: 3.11
+       Exception representation on the stack now consist of two, not three, items.
 
 .. opcode:: PUSH_EXC_INFO
 
-    Pops the three values from the stack. Pushes the current exception to the top of the stack.
-    Pushes the three values originally popped back to the stack.
+    Pops two values from the stack. Pushes the current exception to the top of the stack.
+    Pushes the two values originally popped back to the stack.
     Used in exception handlers.
 
     .. versionadded:: 3.11
 
 
 .. opcode:: WITH_EXCEPT_START
 
-    Calls the function in position 8 on the stack with the top three
-    items on the stack as arguments.
+    Calls the function in position 6 on the stack with the top two
+    items on the stack, as well as a traceback derived from the second item,
+    as arguments.
     Used to implement the call ``context_manager.__exit__(*exc_info())`` when an exception
     has occurred in a :keyword:`with` statement.
 
     .. versionadded:: 3.9
     .. versionchanged:: 3.11
-       The ``__exit__`` function is in position 8 of the stack rather than 7.
-
+       The ``__exit__`` function is in position 6 of the stack rather than 7.
+       Exception representation on the stack now consist of two, not three, items.
 
 .. opcode:: POP_EXCEPT_AND_RERAISE
 

Include/internal/pycore_pyerrors.h

@@ -98,6 +98,10 @@ PyAPI_FUNC(void) _Py_NO_RETURN _Py_FatalRefcountErrorFunc(
 
 #define _Py_FatalRefcountError(message) _Py_FatalRefcountErrorFunc(__func__, message)
 
+
+/* number of items stored in the stack for each exception */
+#define PY_EXC_INFO_STACK_SIZE 2
+
 #ifdef __cplusplus
 }
 #endif

Lib/importlib/_bootstrap_external.py

@@ -371,6 +371,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.11a3 3464 (bpo-45636: Merge numeric BINARY_*/INPLACE_* into
 #                         BINARY_OP)
 #     Python 3.11a3 3465 (Add COPY_FREE_VARS opcode)
+#     Python 3.11a3 3466 (bpo-45711: exc_info on the stack does not include traceback)
 
 #
 # MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -380,7 +381,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3465).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3466).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'