Fix case where some Exceptions have no traceback.

In chained exception if some exceptions does not have tracebacks,
prevent jumping to them.

We also add the assert that the main exception does have a traceback.

This is a port of python/cpython commit 5f3433f210d25d366fcebfb40adf444c8f46cd59

IPython/core/debugger.py

@@ -419,7 +419,12 b' class Pdb(OldPdb):'
                     rep = repr(exc)
                     if len(rep) > 80:
                         rep = rep[:77] + "..."
-                    self.message(f"{prompt} {ix:>3} {rep}")
+                    indicator = (
+                        "  -"
+                        if self._chained_exceptions[ix].__traceback__ is None
+                        else f"{ix:>3}"
+                    )
+                    self.message(f"{prompt} {indicator} {rep}")
             else:
                 try:
                     number = int(arg)
@@ -427,6 +432,12 b' class Pdb(OldPdb):'
                     self.error("Argument must be an integer")
                     return
                 if 0 <= number < len(self._chained_exceptions):
+                    if self._chained_exceptions[number].__traceback__ is None:
+                        self.error(
+                            "This exception does not have a traceback, cannot jump to it"
+                        )
+                        return
+
                     self._chained_exception_index = number
                     self.setup(None, self._chained_exceptions[number].__traceback__)
                     self.print_stack_entry(self.stack[self.curindex])
@@ -438,6 +449,8 b' class Pdb(OldPdb):'
             if CHAIN_EXCEPTIONS:
                 # this context manager is part of interaction in 3.13
                 _chained_exceptions, tb = self._get_tb_and_exceptions(tb_or_exc)
+                if isinstance(tb_or_exc, BaseException):
+                    assert tb is not None, "main exception must have a traceback"
                 with self._hold_exceptions(_chained_exceptions):
                     OldPdb.interaction(self, frame, tb)
             else: