gh-130250: fix regression in traceback.print_last (#130318)

Author: iritkatriel

Doc/library/traceback.rst

@@ -115,14 +115,14 @@ Module-Level Functions
 
 .. function:: print_exc(limit=None, file=None, chain=True)
 
-   This is a shorthand for ``print_exception(sys.exception(), limit, file,
-   chain)``.
+   This is a shorthand for ``print_exception(sys.exception(), limit=limit, file=file,
+   chain=chain)``.
 
 
 .. function:: print_last(limit=None, file=None, chain=True)
 
-   This is a shorthand for ``print_exception(sys.last_exc, limit, file,
-   chain)``.  In general it will work only after an exception has reached
+   This is a shorthand for ``print_exception(sys.last_exc, limit=limit, file=file,
+   chain=chain)``.  In general it will work only after an exception has reached
    an interactive prompt (see :data:`sys.last_exc`).
 
 

Lib/test/test_traceback.py

@@ -510,6 +510,13 @@ def test_print_exception_exc(self):
         traceback.print_exception(Exception("projector"), file=output)
         self.assertEqual(output.getvalue(), "Exception: projector\n")
 
+    def test_print_last(self):
+        self.assertIsNone(getattr(sys, "last_exc", None))
+        sys.last_exc = ValueError(42)
+        output = StringIO()
+        traceback.print_last(file=output)
+        self.assertEqual(output.getvalue(), "ValueError: 42\n")
+
     def test_format_exception_exc(self):
         e = Exception("projector")
         output = traceback.format_exception(e)

Lib/traceback.py

@@ -204,23 +204,23 @@ def _safe_string(value, what, func=str):
 # --
 
 def print_exc(limit=None, file=None, chain=True):
-    """Shorthand for 'print_exception(sys.exception(), limit, file, chain)'."""
+    """Shorthand for 'print_exception(sys.exception(), limit=limit, file=file, chain=chain)'."""
     print_exception(sys.exception(), limit=limit, file=file, chain=chain)
 
 def format_exc(limit=None, chain=True):
     """Like print_exc() but return a string."""
     return "".join(format_exception(sys.exception(), limit=limit, chain=chain))
 
 def print_last(limit=None, file=None, chain=True):
-    """This is a shorthand for 'print_exception(sys.last_exc, limit, file, chain)'."""
+    """This is a shorthand for 'print_exception(sys.last_exc, limit=limit, file=file, chain=chain)'."""
     if not hasattr(sys, "last_exc") and not hasattr(sys, "last_type"):
         raise ValueError("no last exception")
 
     if hasattr(sys, "last_exc"):
-        print_exception(sys.last_exc, limit, file, chain)
+        print_exception(sys.last_exc, limit=limit, file=file, chain=chain)
     else:
         print_exception(sys.last_type, sys.last_value, sys.last_traceback,
-                        limit, file, chain)
+                        limit=limit, file=file, chain=chain)
 
 
 #

Misc/NEWS.d/next/Library/2025-02-19-19-29-19.gh-issue-130250.T00tql.rst

@@ -0,0 +1 @@
+Fix regression in ``traceback.print_last()``.