Enable standard library debugging via config

ipykernel/debugger.py

@@ -270,13 +270,14 @@ class Debugger:
         'richInspectVariables', 'modules'
     ]
 
-    def __init__(self, log, debugpy_stream, event_callback, shell_socket, session):
+    def __init__(self, log, debugpy_stream, event_callback, shell_socket, session, just_my_code):
         self.log = log
         self.debugpy_client = DebugpyClient(log, debugpy_stream, self._handle_event)
         self.shell_socket = shell_socket
         self.session = session
         self.is_started = False
         self.event_callback = event_callback
+        self.just_my_code = just_my_code
         self.stopped_queue = Queue()
 
         self.started_debug_handlers = {}
@@ -515,11 +516,12 @@ async def attach(self, message):
             'port': port
         }
         message['arguments']['logToFile'] = True
-        # Reverts that option for now since it leads to spurious break of the code
-        # in ipykernel source and resuming the execution leads to several errors
-        # in the kernel.
+        # Experimental option to break in non-user code.
+        # The ipykernel source is in the call stack, so the user
+        # has to manipulate the step-over and step-into in a wize way.
         # Set debugOptions for breakpoints in python standard library source.
-        # message['arguments']['debugOptions'] = [ 'DebugStdLib' ]
+        if not self.just_my_code:
+            message['arguments']['debugOptions'] = [ 'DebugStdLib' ]
         return await self._forward_message(message)
 
     async def configurationDone(self, message):

ipykernel/ipkernel.py

@@ -83,7 +83,8 @@ def __init__(self, **kwargs):
                                     self.debugpy_stream,
                                     self._publish_debug_event,
                                     self.debug_shell_socket,
-                                    self.session)
+                                    self.session,
+                                    self.debug_just_my_code)
 
         # Initialize the InteractiveShell subclass
         self.shell = self.shell_class.instance(parent=self,

ipykernel/kernelbase.py

@@ -127,6 +127,15 @@ def _default_ident(self):
     # any links that should go in the help menu
     help_links = List()
 
+    # Experimental option to break in non-user code.
+    # The ipykernel source is in the call stack, so the user
+    # has to manipulate the step-over and step-into in a wize way.
+    debug_just_my_code = Bool(True,
+        help="""Set to False if you want to debug python standard and dependent libraries.
+        """
+    ).tag(config=True)
+
+    # track associations with current request
     # Private interface
 
     _darwin_app_nap = Bool(True,