Linter diagnostics

[bojohnson5]

I'm using ruff for linting my code and see these errors pop up on various lines. I'm curious to know if others have encountered this and if there's a way to fix it. Thanks!

[jpivarski]

If cenns is a ROOT directory, then the data type of cenns['en'] etc. can't be known without reading the file. ruff does static linting, deducing the types of each variable by looking at the code and not running it—it can't possibly know if the data type of cenns['en'] is a TTree (a type that has a array method).

Rather than admitting ignorance, ruff seems to be thinking that the return value of any cenns.__getitem__ is also a directory (ReadOnlyDirectory). I don't know why it would think that: the ReadOnlyDirectory.__getitem__ method doesn't even claim what its output type might be (because it can't):

uproot5/src/uproot/reading.py

Line 2040 in ea207f9

def __getitem__(self, where):

In general, we should be telling linters that we don't have the information they need. It seems like that's the case here—I don't know why ruff thinks it knows this type.

[bojohnson5]

Thanks for the reply. I'll try and dig a little more but for the meantime have turned off the ruff linting.

[jpivarski]

I'd like to keep all Discussions open, so that other people can find them. Thanks!