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Author dacut
Recipients aeros, asvetlov, dacut, gvanrossum, njs, pitrou, vaizki, yselivanov
Date 2019-11-20.21:04:18
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On the completely deprecate reuse_address and rewrite/force folks to use reuse_port proposals, I'm a bit dubious of this approach.

Right now, we have two knobs that directly correspond to (potential) kernel-level socket parameters, SO_REUSEADDR and SO_REUSEPORT. We just chose an unfortunate default for one of them. Otherwise, the behavior is nicely explicit.

Rewriting or forbidding it, even when the user has (essentially) acknowledged they're accepting risks by passing reuse_address=True, seems to fly in the face of this. Users get bitten when we start convoluting logic here (I was just bitten by fcntl.lockf() not actually calling lockf() last month and ended up having to call lockf() via ctypes.).

There are some platforms (Linux pre-3.9 kernels) that don't have SO_REUSEPORT. I wish I could say I don't care about such platforms; alas, I just had to compile Python 3.7 on a system running a 2.6 kernel last month at a client site.

Finally, I've only scratched the surface with my test cases, on single-homed systems, IPv4, and binding to There are a lot of parameters to try here before we decree that reuse_address has no purpose existing, and an OS could later reimplement saner defaults on SO_REUSEADDR.

Changing a default already has some controversy (Yury was -1 on this change). This seems much bigger and I'm not convinced we fully understand its ramifications.

That said, I'll happily implement whatever the consensus ends up being, or consensus as designated by the vBDFL, or wherever that decision needs to come from. :-)
Date User Action Args
2019-11-20 21:04:19dacutsetrecipients: + dacut, gvanrossum, pitrou, njs, asvetlov, yselivanov, vaizki, aeros
2019-11-20 21:04:18dacutsetmessageid: <>
2019-11-20 21:04:18dacutlinkissue37228 messages
2019-11-20 21:04:18dacutcreate