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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"ipdb and \"--simple-prompt\" leads to an eventloop crash","articleBody":"Hi,\r\n\r\nIt does not appear to be currently possible to use the IPython debugger in conjunction with the simple-prompt mode and ipdb (from pypi : `pip install ipdb`).\r\n\r\nThis makes debugging multithreaded applications with ipdb and Emacs impossible (since the only way to break in the right thread is to put the snippet: `import ipdb; ipdb.set_trace()` in the code.\r\n\r\nIf I remove the \"--simple-prompt\" option then I get garbled text such as \"^[[6n^[[Jipdb\u003e ^[[6D^[[6C\" at the ipdb prompt in Emacs since this is a dumb terminal which doesn't understand the special character escapes sent back by prompt_toolkit.\r\n\r\nThe traceback returned when using \"--simple-prompt\" is :\r\n````\r\n [...]\r\n  File \"some_file.py\", line 30, in some_function\r\n    import ipdb; ipdb.set_trace()\r\n  File \"/home/maxim/.virtualenvs/project1/local/lib/python2.7/site-packages/ipdb/__main__.py\", line 97, in set_trace\r\n    p = _init_pdb(context).set_trace(frame)\r\n  File \"/home/maxim/.virtualenvs/project1/local/lib/python2.7/site-packages/ipdb/__main__.py\", line 77, in _init_pdb\r\n    p = debugger_cls(def_colors, context=context)\r\n  File \"/home/maxim/.virtualenvs/project1/local/lib/python2.7/site-packages/IPython/terminal/debugger.py\", line 26, in __init__\r\n    self.pt_init()\r\n  File \"/home/maxim/.virtualenvs/project1/local/lib/python2.7/site-packages/IPython/terminal/debugger.py\", line 68, in pt_init\r\n    self.pt_cli = CommandLineInterface(self._pt_app, eventloop=self.shell._eventloop)\r\nAttributeError: 'TerminalInteractiveShell' object has no attribute '_eventloop'\r\n````\r\n\r\nIt should be trivial to reproduce. Make sure you have `ipdb` installed (`pip install ipdb`).\r\n\r\n1. Create a script such as the following to a file named \"ipdb_eventloop_repro.py\":\r\n\r\n````\r\nprint 'hello'\r\nprint ''\r\nimport ipdb; ipdb.set_trace()\r\nprint 'world'\r\n````\r\n2. In a terminal, start the IPython process in 'simple-prompt' mode like this:\r\n\r\n`ipython --simple-prompt -c \"%run -d ipdb_eventloop_repro.py\"`\r\n\r\n3. Then press 'c' to trigger the crash.\r\n\r\nI'm not sure where the fix should happen: in IPython, or in ipdb? There was an attempt at fixing it on the ipdb side here: https://github.com/gotcha/ipdb/pull/130 but it causes spewing to restart in the dumb shell since it relies on the prompt_toolkit eventloop.\r\n\r\nAny suggestion of a fix? I'd really like to get ipdb + Emacs going :)","author":{"url":"https://github.com/apteryks","@type":"Person","name":"apteryks"},"datePublished":"2017-05-19T22:00:54.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/10577/ipython/issues/10577"}