gh-135511 Fixed NameError and AttributeError lack of the message in IDLE

Lib/idlelib/idle_test/test_run.py

@@ -45,17 +45,24 @@ def __eq__(self, other):
             ('int.reel', AttributeError,
                  "type object 'int' has no attribute 'reel'. "
                  "Did you mean: 'real'?\n"),
+            ('raise NameError("123\\n456")', NameError, "123\n456"),
             )
 
     @force_not_colorized
     def test_get_message(self):
         for code, exc, msg in self.data:
             with self.subTest(code=code):
                 try:
-                    eval(compile(code, '', 'eval'))
+                    if "raise " not in code:
+                        eval(compile(code, '', 'eval'))
+                    else:
+                        exec(compile(code, '', 'exec'))
                 except exc:
-                    typ, val, tb = sys.exc_info()
-                    actual = run.get_message_lines(typ, val, tb)[0]
+                    if "raise " in code:
+                        actual = run.print_exception(in_test=True)
+                    else:
+                        typ, val, tb = sys.exc_info()
+                        actual = run.get_message_lines(typ, val, tb)[0]
                     expect = f'{exc.__name__}: {msg}'
                     self.assertEqual(actual, expect)
 

Lib/idlelib/run.py

@@ -240,15 +240,19 @@ def get_message_lines(typ, exc, tb):
         return traceback.format_exception_only(typ, exc)
 
 
-def print_exception():
+def print_exception(in_test=False): #Only when in test it is True, other it is False
     import linecache
     linecache.checkcache()
     flush_stdout()
-    efile = sys.stderr
+    if not in_test:
+        efile = sys.stderr
+    else:
+        efile = io.StringIO()  #If in test, anything mustn't be printed to sys.stderr
     typ, val, tb = excinfo = sys.exc_info()
     sys.last_type, sys.last_value, sys.last_traceback = excinfo
     sys.last_exc = val
     seen = set()
+    err = io.StringIO()
 
     def print_exc(typ, exc, tb):
         seen.add(id(exc))
@@ -269,13 +273,20 @@ def print_exc(typ, exc, tb):
             print('Traceback (most recent call last):', file=efile)
             exclude = ("run.py", "rpc.py", "threading.py", "queue.py",
                        "debugger_r.py", "bdb.py")
-            cleanup_traceback(tbe, exclude)
+            if not in_test:  #When in test, the rpc.objecttable has no key 'exec'
+                cleanup_traceback(tbe, exclude)
             traceback.print_list(tbe, file=efile)
-        lines = get_message_lines(typ, exc, tb)
+        if ((not isinstance(exc, NameError) and not isinstance(exc, AttributeError))
+            or "\n" not in str(exc)):
+            lines = get_message_lines(typ, exc, tb)
+        else:
+            lines = [f"{typ.__name__}: {str(exc)}"]            
         for line in lines:
             print(line, end='', file=efile)
+            print(line, end='', file=err)
 
     print_exc(typ, val, tb)
+    return err.getvalue()
 
 def cleanup_traceback(tb, exclude):
     "Remove excluded traces from beginning/end of tb; get cached lines"

Misc/NEWS.d/next/IDLE/2025-06-15-09-50-19.gh-issue-135511.2C5EX-.rst

@@ -0,0 +1 @@
+Fix display of :exc:`NameError` and :exc:`AttributeError` with multi-line message.