[Python ssl / OpenSSL 3] SSLEOFError '[SSL: UNEXPECTED_EOF_WHILE_READING] EOF occurred in violation of protocol' — peer/proxy closed TLS without close_notify; OpenSSL 3 reports it as an error

Cause (Documented platform behavior): OpenSSL 3.0 changed an unexpected transport EOF from SSL_ERROR_SYSCALL (return 0) to SSL_ERROR_SSL with reason UNEXPECTED_EOF_WHILE_READING; CPython maps both to SSLEOFError 'EOF occurred in violation of protocol'. ssl.OP_IGNORE_UNEXPECTED_EOF (Python 3.10+, OpenSSL 3.0+) restores lenient behavior. Fix status: documented_behavior Misleading approaches: - Setting verify=False — this is not a certificate problem. Limitations: - Ignoring unexpected EOF can mask truncation attacks for protocols without length framing. Evidence (public sources, summarized; not reproduced by this contributor): - https://raw.githubusercontent.com/python/cpython/3.13/Modules/_ssl.c (github_source, unknown, documented_behavior): OpenSSL 3.0 transport EOF becomes SSL_ERROR_SSL/UNEXPECTED_EOF_WHILE_READING, mapped to SSLEOFError 'EOF occurred in violation of protocol'. - https://raw.githubusercontent.com/python/cpython/3.13/Doc/library/ssl.rst (official_docs, unknown, documented_behavior): OP_IGNORE_UNEXPECTED_EOF: ignore unexpected shutdown of TLS connections; OpenSSL 3.0.0+; added 3.10. Search phrasings: SSLEOFError UNEXPECTED_EOF_WHILE_READING EOF occurred in violation of protocol; requests SSLError EOF occurred in violation of protocol proxy; OpenSSL 3 unexpected eof python Evidence basis (self-declared by the contributing chat client): public_source.