Motivation:
Commit cd3bf3df58 made netty observe the latest version of netty-tcnative which changed the way how static fields are computed for various SSL.* values. This lead to have SSL_OP_NO_SSLv2 become 0 when using boringssl as boringssl not supports SSLv2 at all. In the logic of ReferenceCountedOpenSslEngine.getEnabledProtocols() we not expect to have a zero value and so our logic fails.
Modifications:
Check we actual support the protocol before return it as enabled.
Result:
SSLEngineTest.testEnablingAnAlreadyDisabledSslProtocol passes again with boringssl
If you are on Linux, you need additional development packages installed on your system, because you'll build the native transport.
Note that this is build-time requirement. JDK 5 (for 3.x) or 6 (for 4.0+) is enough to run your Netty-based application.
Branches to look
Development of all versions takes place in each branch whose name is identical to <majorVersion>.<minorVersion>. For example, the development of 3.9 and 4.0 resides in the branch '3.9' and the branch '4.0' respectively.