logOptionsHandle -> logSend is not thread-safe about rio HOT 3 CLOSED

Can you provide a minimal repro? And do you know if you're logging in UTF-8? It's known to potentially interleave output for non-UTF-8 output.

from rio.

I've been logging to stderr in ubuntu:18.04 docker image. And it turn out that it stderr is non-UTF-8 be default:

Prelude GHC.IO.Handle.Internals GHC.IO.Handle.Types GHC.IO.Handle System.IO> wantWritableHandle "a" stderr (\x -> pure $ haCodec x)
Just ASCII

root@3b1b7a80967f:/# LANG=C.UTF-8  /usr/local/bin/stack ghci
Prelude System.IO GHC.IO.Handle GHC.IO.Handle.Internals GHC.IO.Handle.Types> wantWritableHandle "a" stderr (\x -> pure $ haCodec x)
Just UTF-8

This explains why everything worked fine on my Mac, but failed after deploying to K8.
Thank you for a prompt reply!

Is this anything that should be fixed, or just behavior by design?

from rio.

It's definitely "by design" in this case: the text package unfortunately does I/O very poorly, and we're relying on its behavior for non-UTF-8 backends. We could theoretically do some locking, but that will only fix the issue within rio; other pieces of the system still working directly with stderr could have issues. Overall, my preference is to fix this with documentation, and advertise loudly that non-interleaving is only accounted for with UTF-8 output. Would you be open to writing a PR with such a doc fix?

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