TODO: Decorate asserts with helpful messages

[ghost]

See changes made in #3023, #2057.

Enhancing an assert with a meaningful message
is an easy way to make your first contribution to the
pandas project.

[cpcloud]

Would a script to find such things be helpful? I think I can cook one up using ast or some such other magik.

[ghost]

if you'd like to make one, sure. we'll open another #2916 for it.
but the intent was not just re asserts lacking a message, but also those lacking a good message.

[cpcloud]

ah ok. no script for that :).

[cpcloud]

python -O is weird. Whoa, @y-p did you do all of those conversions by hand? This could probably be generalized to "Decorate explicitly raised exceptions with helpful messages". Also, getting rid of all of the generic Exception calls is probably a good idea IMHO.

[cpcloud]

Getting rid of all the generic Exception calls is probably a long term goal, since there's probably all kinds of catching these guys throughout the codebase. To the ast module, batman!

[ghost]

yea manually, with the aid of an editor macro. it's a one time thing not worth automating beyond.

as for catching Exception, I agree it's often a bad idea, and has caused some corner cases,
especially in deep call stack where unintended consequences can rise. can't be helped though,
sometimes. especially when you're speculatively relying on user provided lambdas and want to recover
gracefully.

[ghost]

Eternal, but largely addressed by #3770.