UnboundLocalError - chunk_size is not always set in middleware method

[CasperWA]

In the AddWarnings middleware, the chunk_size variable may not always be set, resulting in an UnboundLocalError exception being thrown.

The relevant lines of code can be found here.

The issue is (my guess), if the body is empty the for-loop is never entered, hence chunk_size is not set.
Solution: Any variables always reached should be preset at the beginning of functions/methods.

[ml-evs]

Written a few tests to try to trigger this, but even with an empty b"" response the first loop of response.body_iterator sets the chunk size appropriately. Do you know what triggered this for you? Obviously can just fix the code to set a default chunk_size to avoid this but just trying to understand

[CasperWA]

Huh - you can see the error from a test in the gateway repository here.
I'm testing that the response from the OPTIMADE server will time out, essentially.

If it's not the content of the response.body_iterator, then I don't know?

[ml-evs]

Huh - you can see the error from a test in the gateway repository here. I'm testing that the response from the OPTIMADE server will time out, essentially.

If it's not the content of the response.body_iterator, then I don't know?

Right, hadn't appreciated the timeout aspect. Well #1336 should fix it either way, but probably not something we can test here

[ml-evs]

Just noticed that we are running into the exact same bug with FastAPI 0.85 here: #1334

[ml-evs]

Going to reopen this until I can verify that most responses still have an appropriate chunk size, not the default of 1 byte

[ml-evs]

Going to reopen this until I can verify that most responses still have an appropriate chunk size, not the default of 1 byte

Seems fine! Tested by adding a breakpoint in the case of chunk_size = 0, launching the server then running the validator, and it wasn't triggered. Will close this and make a patch release. If I get time I'll play around with whichever test (looks like API hint tests) was actually failing in the FastAPI update PR but maybe not today!

[CasperWA]

So very much appreciated! Thank you! ❤️