Backport PR #12758: Fix issue #11615 handle unicode encode error when print stack trace

IPython/core/interactiveshell.py

@@ -2075,13 +2075,17 b' class InteractiveShell(SingletonConfigurable):'
         except KeyboardInterrupt:
             print('\n' + self.get_exception_only(), file=sys.stderr)
 
-    def _showtraceback(self, etype, evalue, stb):
+    def _showtraceback(self, etype, evalue, stb: str):
         """Actually show a traceback.
 
         Subclasses may override this method to put the traceback on a different
         place, like a side channel.
         """
-        print(self.InteractiveTB.stb2text(stb))
+        val = self.InteractiveTB.stb2text(stb)
+        try:
+            print(val)
+        except UnicodeEncodeError:
+            print(val.encode("utf-8", "backslashreplace").decode())
 
     def showsyntaxerror(self, filename=None, running_compiled_code=False):
         """Display the syntax error that just occurred.

IPython/core/tests/test_interactiveshell.py

@@ -449,6 +449,25 b' class InteractiveShellTestCase(unittest.TestCase):'
             # Reset the custom exception hook
             ip.set_custom_exc((), None)
     
+    @mock.patch("builtins.print")
+    def test_showtraceback_with_surrogates(self, mocked_print):
+        values = []
+
+        def mock_print_func(value, sep=" ", end="\n", file=sys.stdout, flush=False):
+            values.append(value)
+            if value == chr(0xD8FF):
+                raise UnicodeEncodeError("utf-8", chr(0xD8FF), 0, 1, "")
+
+        # mock builtins.print
+        mocked_print.side_effect = mock_print_func
+
+        # ip._showtraceback() is replaced in globalipapp.py.
+        # Call original method to test.
+        interactiveshell.InteractiveShell._showtraceback(ip, None, None, chr(0xD8FF))
+
+        self.assertEqual(mocked_print.call_count, 2)
+        self.assertEqual(values, [chr(0xD8FF), "\\ud8ff"])
+
     def test_mktempfile(self):
         filename = ip.mktempfile()
         # Check that we can open the file again on Windows