python 3.4 AssertionError in pycharm debugger

Question

I have Pycharm 3.1 installed (latest version) which supposedly supports python 3.4, however, this morning it started throwing exceptions whenever I run debugger. Is there anything I can do to fix this AssertionError?

    C:\Python34\python.exe "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py" --multiproc --client 127.0.0.1 --port xx --file C:/Users/xx/PycharmProjects/drop/my_file.py
Connected to pydev debugger (build 133.881)
pydev debugger: process 8492 is connecting

None
Exception in thread pydevd.CheckAliveThread:
Traceback (most recent call last):
  File "C:\Python34\lib\threading.py", line 921, in _bootstrap_inner
    self.run()
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd_comm.py", line 252, in run
    self.OnRun()
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 187, in OnRun
    self.stop()
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd_comm.py", line 262, in stop
    _Thread_stop(self)
  File "C:\Python34\lib\threading.py", line 990, in _stop
    assert not lock.locked()
AssertionError

Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError
Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 3.1\helpers\pydev\pydevd.py", line 996, in trace_dispatch
    if not t.isAlive():
  File "C:\Python34\lib\threading.py", line 1120, in is_alive
    self._wait_for_tstate_lock(False)
  File "C:\Python34\lib\threading.py", line 1076, in _wait_for_tstate_lock
    assert self._is_stopped
AssertionError

Process finished with exit code -1

-- Edit --

I ended up deleting the .py file and recreating the code in a new file, after that, debugger works correctly. I am not sure what corrupts these files, but I have noticed it has happened on several different occasions. AssertionError was one of those times. Another time a .py file got corrupted and the interpreter was throwing an exception that I haven't defined a coding style for unicode char support, even though I had

# -*- coding: utf-8 -*-

What surprised me, even after deleting the whole code (including # -- coding: utf-8 --) and basically calling a simple print() func it would still continue throwing the error! Then again I ended up completely deleting the file and starting from scratch. I felt really shocked, I have no idea how this happened.

Answer 1

I meet this problem by using PyCharm 3.1.1 and Python 3.4.0 in Windows.

This is a bug(http://youtrack.jetbrains.com/issue/PY-12317), which is marked "Fixed in 3.1.2".

Thus, I download PyCharm 3.1.2RC2(build 133.1143) in JetBrains PyCharm Preview (EAP) page. And, that version solved this problem.