bpo-45711: Change exc_info related APIs to derive type and traceback from the exception instance (GH-29780)

4 files changed, 47 insertions, 4 deletions

diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst
index 5d90248..27feab9 100644
--- a/Doc/c-api/exceptions.rst
+++ b/Doc/c-api/exceptions.rst
@@ -482,7 +482,6 @@ Querying the error indicator
    to an exception that was *already caught*, not to an exception that was
    freshly raised.  This function steals the references of the arguments.
    To clear the exception state, pass ``NULL`` for all three arguments.
-   For general rules about the three arguments, see :c:func:`PyErr_Restore`.
 
    .. note::
 
@@ -493,6 +492,12 @@ Querying the error indicator
 
    .. versionadded:: 3.3
 
+   .. versionchanged:: 3.11
+      The ``type`` and ``traceback`` arguments are no longer used and
+      can be NULL. The interpreter now derives them from the exception
+      instance (the ``value`` argument). The function still steals
+      references of all three arguments.
+
 
 Signal Handling
 ===============
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 175fc09..7d1b21f 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -396,9 +396,14 @@ always available.
    ``(type, value, traceback)``.  Their meaning is: *type* gets the type of the
    exception being handled (a subclass of :exc:`BaseException`); *value* gets
    the exception instance (an instance of the exception type); *traceback* gets
-   a :ref:`traceback object <traceback-objects>` which encapsulates the call
-   stack at the point where the exception originally occurred.
-
+   a :ref:`traceback object <traceback-objects>` which typically encapsulates
+   the call stack at the point where the exception last occurred.
+
+   .. versionchanged:: 3.11
+      The ``type`` and ``traceback`` fields are now derived from the ``value``
+      (the exception instance), so when an exception is modified while it is
+      being handled, the changes are reflected in the results of subsequent
+      calls to :func:`exc_info`.
 
 .. data:: exec_prefix
 
diff --git a/Doc/reference/simple_stmts.rst b/Doc/reference/simple_stmts.rst
index bb1209d..3d02074 100644
--- a/Doc/reference/simple_stmts.rst
+++ b/Doc/reference/simple_stmts.rst
@@ -655,6 +655,12 @@ and information about handling exceptions is in section :ref:`try`.
     The ``__suppress_context__`` attribute to suppress automatic display of the
     exception context.
 
+.. versionchanged:: 3.11
+    If the traceback of the active exception is modified in an :keyword:`except`
+    clause, a subsequent ``raise`` statement re-raises the exception with the
+    modified traceback. Previously, the exception was re-raised with the
+    traceback it had when it was caught.
+
 .. _break:
 
 The :keyword:`!break` statement
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
index 8db26cd..6853c04 100644
--- a/Doc/whatsnew/3.11.rst
+++ b/Doc/whatsnew/3.11.rst
@@ -181,6 +181,12 @@ Other CPython Implementation Changes
   hash-based pyc files now use ``siphash13``, too.
   (Contributed by Inada Naoki in :issue:`29410`.)
 
+* When an active exception is re-raised by a :keyword:`raise` statement with no parameters,
+  the traceback attached to this exception is now always ``sys.exc_info()[1].__traceback__``.
+  This means that changes made to the traceback in the current :keyword:`except` clause are
+  reflected in the re-raised exception.
+  (Contributed by Irit Katriel in :issue:`45711`.)
+
 New Modules
 ===========
 
@@ -266,6 +272,16 @@ sqlite3
   (Contributed by Erlend E. Aasland in :issue:`45828`.)
 
 
+sys
+---
+
+* :func:`sys.exc_info` now derives the ``type`` and ``traceback`` fields
+  from the ``value`` (the exception instance), so when an exception is
+  modified while it is being handled, the changes are reflected in
+  the results of subsequent calls to :func:`exc_info`.
+  (Contributed by Irit Katriel in :issue:`45711`.)
+
+
 threading
 ---------
 
@@ -579,6 +595,17 @@ New Features
   suspend and resume tracing and profiling.
   (Contributed by Victor Stinner in :issue:`43760`.)
 
+* :c:func:`PyErr_SetExcInfo()` no longer uses the ``type`` and ``traceback``
+  arguments, the interpreter now derives those values from the exception
+  instance (the ``value`` argument). The function still steals references
+  of all three arguments.
+  (Contributed by Irit Katriel in :issue:`45711`.)
+
+* :c:func:`PyErr_GetExcInfo()` now derives the ``type`` and ``traceback``
+  fields of the result from the exception instance (the ``value`` field).
+  (Contributed by Irit Katriel in :issue:`45711`.)
+
+
 Porting to Python 3.11
 ----------------------