excepthook blocks exceptions on Py2.6

[brian-team]

excepthook blocks exceptions on Py2.6

[mstimberg]

Do I understand you correctly that it blocks exceptions in non-Brian programs? How does the except hook get registered if Brian isn't imported?

Whatever the issue is, I think we should have a preference to switch off the except hook.

[thesamovar]

Something like this:

import brian2
raise ValueError
print "This doesn't happen"

Will just silently terminate.

I guess it's a bug in how our excepthook works on Py 2.6?

[mstimberg]

It turned out this wasn't a problem with the excepthook but a more general issue with logging: Under Python 2.7+ it's ok to use something like setLevel('DEBUG') (which we use when setting the log levels from the preference file), but in Python 2.6, while not raising an error this leads to comparisons like 10 >= 'DEBUG' later on which then results in no messages being logged :-/
I added a translation from string to number to make this work again. I added a dictionary with the translation, even though such a translation already exists in the logging module: logging.getLevelName('DEBUG') will return 10 -- but the name and the documentation only mention the other direction (logging.getLevelName(10) == 'DEBUG') so I did not want to rely on this.

And this shows a limit of our test suite by the way: We are currently testing the logging system by capturing messages with a special handler -- unfortunately this does not capture problems in the configuration of a handler, as the one in this issue...

[thesamovar]

Nice fix! I don't think we should worry about the test suite - you can never make it perfect I guess.