How to make peace with needed nested import statements for Ruff E402?

[alanwilter]

I use this lines a lot in several projects.

import matplotlib
import numpy as np

matplotlib.use("Agg")

from matplotlib import pyplot as plt
from matplotlib.backends.backend_pdf import PdfPages

There's no other way that I know to set the matplotlib backend. But by doing so this will trigger E402.

isort has some ways of handling that (see here).

Of course I can fill lots of # noqa: E402 but this is so ugly.

Ideally, Ruff/isort should be smart enough to know these cases.

Also, perhaps, page E402 (and all others when reasonable) should show how to silence this warning if the user knows what's doing.

[konstin]

Could you share more details why matplotlib.use fails if it's after the other imports? https://matplotlib.org/stable/api/matplotlib_configuration_api.html#matplotlib.use reads like it should be possible.

isort has some ways of handling that (see here).

Of course I can fill lots of # noqa: E402 but this is so ugly.

isort action comments look similar to the noqa comments to me, could you give an example of how they are different?

[alanwilter]

If I load from matplotlib import pyplot as plt before matplotlib.use("Agg") it will be in interactive mode no matter what I do after. (ok, I can use matplotlib.pyplot.ioff()), but it will be slower to start and, if running remotely, it will start X11 service on my mac.

Another solution would be:

import matplotlib
import numpy as np

from matplotlib.backends.backend_pdf import PdfPages
from matplotlib import pyplot as plt # need to be after the line above, but Ruff isort doesn't let

[charliermarsh]

I've run into this matplotlib pattern before. I think it's actually reasonable for us to allow matplotlib.use calls to intersperse imports... In practice, I suspect it will strictly reduce false positives, with no false negatives.

[charliermarsh]

I'll PR it and see what the ecosystem checks say.

[alanwilter]

You guys are amazing. Father Xmas won't forget you ;-)