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Author trygveaa
Recipients trygveaa
Date 2021-05-05.14:22:11
SpamBayes Score -1.0
Marked as misclassified Yes
Message-id <>
This issue is a regression in Python 3.9. It was recently fixed in main/3.10, but I'm opening this issue to request that it is fixed in 3.9 as well since it breaks certain Python scripts running in WeeChat.

I have a C application which is using the Python/C API and is running multiple python subinterpreters. One of those subinterpreters is running a script which is reading data from a non-blocking ssl socket. When there is no more data to read, trying to read throws `ssl.SSLWantReadError` which is handled by the script. However, if a script in another subinterpreter imports _ssl, the SSLWantReadError exceptions thrown in the first script now have a different class instance, so they are not catched anymore.

This is a regression in 3.9. It didn't happen in 3.8. The commit that introduced the issue is
The commit that fixes the issue in 3.10 is

I have attached a C program to reproduce the issue. It seems I can only attach one file per comment, so the python script that program runs will follow in the next commit. It connects to an ssl socket, so you need to have that running first. That can be started by running this:

openssl req -x509 -nodes -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -subj '/'
openssl s_server -key key.pem -cert cert.pem -accept 1234

The script will output this when the issue is not present (so in 3.8 and main):
no data
no data

And this when the issue is present (in 3.9):
no dataunknown error: The operation did not complete (read) (_ssl.c:2627)
exception name: SSLWantReadError
SSLWantReadError id: 93893206532320
exception id: 93893207118800
Date User Action Args
2021-05-05 14:22:11trygveaasetrecipients: + trygveaa
2021-05-05 14:22:11trygveaasetmessageid: <>
2021-05-05 14:22:11trygveaalinkissue44050 messages
2021-05-05 14:22:11trygveaacreate