gh-102755: PyErr_DisplayException only in ABI >= 3.12. Tests cover PyErr_Display as well (GH-102849)

Author: iritkatriel

Include/pythonrun.h

@@ -12,7 +12,10 @@ PyAPI_FUNC(PyObject *) Py_CompileString(const char *, const char *, int);
 PyAPI_FUNC(void) PyErr_Print(void);
 PyAPI_FUNC(void) PyErr_PrintEx(int);
 PyAPI_FUNC(void) PyErr_Display(PyObject *, PyObject *, PyObject *);
+
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030C0000
 PyAPI_FUNC(void) PyErr_DisplayException(PyObject *);
+#endif
 
 
 /* Stuff with no proper home (yet) */

Lib/test/test_traceback.py

@@ -394,18 +394,22 @@ def get_exception(self, callable, slice_start=0, slice_end=-1):
 
 
 class CAPIExceptionFormattingMixin:
+    LEGACY = 0
+
     def get_exception(self, callable, slice_start=0, slice_end=-1):
         from _testcapi import exception_print
         try:
             callable()
             self.fail("No exception thrown.")
         except Exception as e:
             with captured_output("stderr") as tbstderr:
-                exception_print(e)
+                exception_print(e, self.LEGACY)
             return tbstderr.getvalue().splitlines()[slice_start:slice_end]
 
     callable_line = get_exception.__code__.co_firstlineno + 3
 
+class CAPIExceptionFormattingLegacyMixin(CAPIExceptionFormattingMixin):
+    LEGACY = 1
 
 @requires_debug_ranges()
 class TracebackErrorLocationCaretTestBase:
@@ -912,6 +916,16 @@ class CPythonTracebackErrorCaretTests(
     Same set of tests as above but with Python's internal traceback printing.
     """
 
+@cpython_only
+@requires_debug_ranges()
+class CPythonTracebackErrorCaretTests(
+    CAPIExceptionFormattingLegacyMixin,
+    TracebackErrorLocationCaretTestBase,
+    unittest.TestCase,
+):
+    """
+    Same set of tests as above but with Python's legacy internal traceback printing.
+    """
 
 class TracebackFormatTests(unittest.TestCase):
 

Modules/_testcapi/exceptions.c

@@ -40,12 +40,22 @@ static PyObject *
 exception_print(PyObject *self, PyObject *args)
 {
     PyObject *exc;
+    int legacy = 0;
 
-    if (!PyArg_ParseTuple(args, "O:exception_print", &exc)) {
+    if (!PyArg_ParseTuple(args, "O|i:exception_print", &exc, &legacy)) {
         return NULL;
     }
-
-    PyErr_DisplayException(exc);
+    if (legacy) {
+        PyObject *tb = NULL;
+        if (PyExceptionInstance_Check(exc)) {
+            tb = PyException_GetTraceback(exc);
+        }
+        PyErr_Display((PyObject *) Py_TYPE(exc), exc, tb);
+        Py_XDECREF(tb);
+    }
+    else {
+        PyErr_DisplayException(exc);
+    }
     Py_RETURN_NONE;
 }