Backport PR #10261: Add Ctrl-Z shortcut (suspend) in terminal debugger

Closes gh-10254

docs/source/whatsnew/pr/debugger-ctrl-z.rst

@@ -0,0 +1,2 b''
+Pressing Ctrl-Z in the terminal debugger now suspends IPython, as it already
+does in the main terminal prompt.

IPython/terminal/debugger.py

@@ -1,88 +1,100 b''
+import signal
+import sys
+
 from IPython.core.debugger import Pdb
 
 from IPython.core.completer import IPCompleter
 from .ptutils import IPythonPTCompleter
+from .shortcuts import suspend_to_bg
 
+from prompt_toolkit.filters import Condition
+from prompt_toolkit.keys import Keys
+from prompt_toolkit.key_binding.manager import KeyBindingManager
 from prompt_toolkit.token import Token
 from prompt_toolkit.shortcuts import create_prompt_application
 from prompt_toolkit.interface import CommandLineInterface
 from prompt_toolkit.enums import EditingMode
-import sys
 
 
 class TerminalPdb(Pdb):
     def __init__(self, *args, **kwargs):
         Pdb.__init__(self, *args, **kwargs)
         self._ptcomp = None
         self.pt_init()
 
     def pt_init(self):
         def get_prompt_tokens(cli):
             return [(Token.Prompt, self.prompt)]
 
         def patch_stdout(**kwargs):
             return self.pt_cli.patch_stdout_context(**kwargs)
 
         if self._ptcomp is None:
             compl = IPCompleter(shell=self.shell,
                                         namespace={},
                                         global_namespace={},
                                         use_readline=False,
                                         parent=self.shell,
                                        )
             self._ptcomp = IPythonPTCompleter(compl, patch_stdout=patch_stdout)
 
+        kbmanager = KeyBindingManager.for_prompt()
+        supports_suspend = Condition(lambda cli: hasattr(signal, 'SIGTSTP'))
+        kbmanager.registry.add_binding(Keys.ControlZ, filter=supports_suspend
+                                      )(suspend_to_bg)
+
         self._pt_app = create_prompt_application(
                             editing_mode=getattr(EditingMode, self.shell.editing_mode.upper()),
+                            key_bindings_registry=kbmanager.registry,
                             history=self.shell.debugger_history,
                             completer= self._ptcomp,
                             enable_history_search=True,
                             mouse_support=self.shell.mouse_support,
                             get_prompt_tokens=get_prompt_tokens
         )
         self.pt_cli = CommandLineInterface(self._pt_app, eventloop=self.shell._eventloop)
 
     def cmdloop(self, intro=None):
         """Repeatedly issue a prompt, accept input, parse an initial prefix
         off the received input, and dispatch to action methods, passing them
         the remainder of the line as argument.
 
         override the same methods from cmd.Cmd to provide prompt toolkit replacement.
         """
         if not self.use_rawinput:
             raise ValueError('Sorry ipdb does not support use_rawinput=False')
 
         self.preloop()
 
         try:
             if intro is not None:
                 self.intro = intro
             if self.intro:
                 self.stdout.write(str(self.intro)+"\n")
             stop = None
             while not stop:
                 if self.cmdqueue:
                     line = self.cmdqueue.pop(0)
                 else:
                     self._ptcomp.ipy_completer.namespace = self.curframe_locals
                     self._ptcomp.ipy_completer.global_namespace = self.curframe.f_globals
                     try:
                         line = self.pt_cli.run(reset_current_buffer=True).text
                     except EOFError:
                         line = 'EOF'
                 line = self.precmd(line)
                 stop = self.onecmd(line)
                 stop = self.postcmd(stop, line)
             self.postloop()
         except Exception:
             raise
 
 
 def set_trace(frame=None):
     """
     Start debugging from `frame`.
 
     If frame is not specified, debugging starts from caller's frame.
     """
     TerminalPdb().set_trace(frame or sys._getframe().f_back)