StopIteration exception

Question

function

def _copying(self):
    result = self.result.toPlainText().strip().split('\n')
    to_copy = '\n'.join(result)

    pyperclip.copy(to_copy)

in the MainWindow() of my PyQt5 project raises an exception "StopIteration" in contextlib.py _GeneratorContextManager(), line 119 'next(self.gen)'. result is a ui.TextEdit object. Could u please tell me what does it mean? Google says i should wrap my func into with-construction, but i don't really inderstand how, and don't sure it's a good idea.

Debugger says:

__exception__ = {tuple} <class 'tuple'>: (<class 'StopIteration'>, StopIteration(), <traceback object at 0x045DA918>)
 0 = {type} <class 'StopIteration'>
  args = {getset_descriptor} <attribute 'args' of 'BaseException' objects>
  value = {member_descriptor} <member 'value' of 'StopIteration' objects>
 1 = {StopIteration} 
  args = {tuple} <class 'tuple'>: ()
  value = {NoneType} None
 2 = {traceback} <traceback object at 0x045DA918>
  tb_frame = {frame} __exit__ [contextlib.py:119]  id:54111736
  tb_lasti = {int} 16
  tb_lineno = {int} 119
  tb_next = {NoneType} None
 __len__ = {int} 3

Console says nothing. But the project is crashing.

That's not a traceback. A traceback is the thing from "Traceback (most recent call last):" up to "WhateverError: stuff broke because reasons" that gets printed when an exception isn't handled. You probably can't show us one, because this exception is normal and gets handled. — user2357112, Feb 01 '19 at 07:48
What do you mean by crashing? It just stops abruptly with no exception? Do you only see the StopIteration in the debugger? — Alex Hall, Feb 01 '19 at 07:50
@AlexHall Yes, it's what i mean by crashing. And yes, i only see this exception in the debugger. Console isn't show any problems. — Age of Creations, Feb 01 '19 at 09:39
@AlexHall well. The problem is solved by herself. Obviously there's another reason of crashes. Could it be something about memory? — Age of Creations, Feb 01 '19 at 09:47

score 0 · Accepted Answer · answered Feb 01 '19 at 07:42

0

That StopIteration is completely normal and expected. It's part of the normal operation of contextlib.contextmanager. It's supposed to happen, and it's caught and handled immediately; if it doesn't happen, there's a problem.

I don't know how you've even ended up at the point where you're looking at this exception, considering how it never escapes the contextlib internals, but if you're blaming it for your code's problems, you're blaming the wrong thing.

answered Feb 01 '19 at 07:42

user2357112

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Oh wow. Now it works without any problems. I'll will reproduce the bug, but i still don'h have any ideas about the reason of crashes. Could it be something about memory? – Age of Creations Feb 01 '19 at 09:45

StopIteration exception

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