fix: guard TLS 1.3 minimum-version behind capability probe#475
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LibreSSL (shipped with macOS system Python) does not support TLS 1.3. The random SSL-context pool unconditionally included a command that sets `minimum_version = TLSv1_3`, which raises `ValueError: Unsupported protocol version` on LibreSSL ~25% of the time. Add a `_tls13_supported()` probe that tests whether the platform can actually set TLS 1.3 as a minimum version, and only include that command in the random pool when the probe passes. The probe runs once at import time and caches the result in `_TLS13_OK`. On OpenSSL (Linux, Homebrew Python, venvs): TLS 1.3 command is included as before — full anti-fingerprinting surface preserved. On LibreSSL (macOS system Python): TLS 1.3 command is excluded — no crashes, still 3 randomization options (no-op, TLS 1.2 max, disable tickets).
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fix: guard TLS 1.3 minimum-version behind capability probe
LibreSSL (shipped with macOS system Python) does not support TLS 1.3.
The random SSL-context pool unconditionally included a command that sets
minimum_version = TLSv1_3, which raisesValueError: Unsupported protocol versionon LibreSSL ~25% of the time.Add a
_tls13_supported()probe that tests whether the platform canactually set TLS 1.3 as a minimum version, and only include that command
in the random pool when the probe passes. The probe runs once at import
time and caches the result in
_TLS13_OK.On OpenSSL (Linux, Homebrew Python, venvs): TLS 1.3 command is included
as before — full anti-fingerprinting surface preserved.
On LibreSSL (macOS system Python): TLS 1.3 command is excluded — no
crashes, still 3 randomization options (no-op, TLS 1.2 max, disable
tickets).