Script randomly exits for seemingly no reason with strange traceback

[Andrew Berg]

It's a rare occurrence, but sometimes my script will terminate and I get
this:

Traceback (most recent call last):
File "C:\path\to\script\script.py", line 992, in <module>

That's it. And the line number is always the last line of the file
(which in my case is a blank line). I have not seen this on Linux (where
my script can run for days or weeks on a remote server), but only on
Windows where I do most of my testing (and it typically only runs for
minutes at a time). There may be bugs in my program, but I don't see how
Python should ever print a traceback like this.

 

[Steven D'Aprano]

It's a rare occurrence, but sometimes my script will terminate and I get
this:

Traceback (most recent call last):
File "C:\path\to\script\script.py", line 992, in <module>

That's it. And the line number is always the last line of the file
(which in my case is a blank line).

Is it reproducible? That is, can you demonstrate a script which will
*always* show this failure?

I have not seen this on Linux (where
my script can run for days or weeks on a remote server), but only on
Windows where I do most of my testing (and it typically only runs for
minutes at a time). There may be bugs in my program, but I don't see how
Python should ever print a traceback like this.

Which version of Python, which version of Windows?

If you upgrade Python, does the problem go away?

If you perturb your script (add a few blank lines at the end, or a
comment), does it go away?

 

[inq1ltd]

Check your code in that module for open parenthesis something like below..
Most likely your code is looking for the closing parenthesis.
Start at the bottom and move up.

pink = str(self.RecordKey[2] <--missing ")"

jimonlinux

 

[Steven D'Aprano]

Check your code in that module for open parenthesis something like
below.. Most likely your code is looking for the closing parenthesis.
Start at the bottom and move up.

pink = str(self.RecordKey[2] <--missing ")"

If that were the case, the module wouldn't run at all, it would
consistently raise SyntaxError before running.

 

[Andrew Berg]

Which version of Python, which version of Windows?

I keep that information in my signature for every post I make to this list.
CPython 3.2.2 | Windows NT 6.1.7601.17640

If you upgrade Python, does the problem go away?

I use the most recent stable version. It would be hard to say if the
problem went away since it's rare and random AFAICT.

Do you call on potentially-buggy external modules?

It imports one module that does little more than define a few simple
functions. There's certainly no (intentional) interpreter hackery at work.

 

[Steven D'Aprano]

I keep that information in my signature for every post I make to this
list. CPython 3.2.2 | Windows NT 6.1.7601.17640

Why so you do. Did you expect that people would read it? As a rule, sigs
fade into the background -- my mail client colours it grey, my news
client colours it light blue, and I generally don't even notice it.

The Zen of Python applies here: explicit is better than implicit.

I use the most recent stable version. It would be hard to say if the
problem went away since it's rare and random AFAICT.

I suggest you raise an issue on the bug tracker. If you can't reproduce
the bug, it's unlikely to be fixed, but you might get lucky.

 

[Andrew Berg]

I suggest you raise an issue on the bug tracker. If you can't reproduce
the bug, it's unlikely to be fixed, but you might get lucky.

Since I can't narrow it down to any specific circumstance or code, I'll
gather information from a build of the interpreter with debugging
enabled first.

 

[Chris Angelico]

It imports one module that does little more than define a few simple
functions. There's certainly no (intentional) interpreter hackery at work.

If it's safe for you to do so (copyright/licence etc), it may be worth
posting the code along with your bug report, just in case. I had some
REALLY weird issues from embedding Python that derived, ultimately,
from buggy ref management - one such case came from forgetting to
incref None; it took me a long time to track it down, because the
problem didn't actually surface until the interpreter was shutting
down.

ChrisA

 

[John Nagle]

Are you doing a conditional import, one that takes place after load
time? If you do an import within a function or class, it is executed
when the code around it executes. If you import a file with a
syntax error during execution, you could get the error message you're
getting.

John Nagle

 

[Andrew Berg]

Are you doing a conditional import, one that takes place after load
time? If you do an import within a function or class, it is executed
when the code around it executes. If you import a file with a
syntax error during execution, you could get the error message you're
getting.

It does have conditional imports, but the tracebacks don't occur while
that function is running (it's executed once, and this happens well after).