Conditionally add aliases for TLS 1.3 constants

[michaelklishin]

so that the module does not fail to load on/with older OpenSSL versions that do not support TLS 1.3.

References #629, #646.

Closes #652.

[michaelklishin]

I could not get hold of an environment that would have

• Ruby 2.6 or 2.7, and
• An OpenSSL version that does not support TLS 1.3 (so, OpenSSL 1.0.x?)

but if I extend the same idea to a hypothetical future version by adding one more snippet:

if defined?(OpenSSL::SSL::TLS1_4_VERSION)
  TLS_VERSION_ALIASES["1.4"]                        = OpenSSL::SSL::TLS1_4_VERSION
  TLS_VERSION_ALIASES[:TLSv1_4]                     = OpenSSL::SSL::TLS1_4_VERSION
  TLS_VERSION_ALIASES[OpenSSL::SSL::TLS1_4_VERSION] = OpenSSL::SSL::TLS1_4_VERSION
end

the module still loads successfully.

[michaelklishin]

@dup2 @arashm @tindron @doconnor-clintel can you please try this PR in your environments where OpenSSL does not provide TLS 1.3 support?

[tindron]

@dup2 @arashm @tindron @doconnor-clintel can you please try this PR in your environments where OpenSSL does not provide TLS 1.3 support?

The earlier lines referencing OpenSSL::SSL::TLS1_3_VERSION are still present:

randy@randy-VirtualBox:~/git/bunny$ rspec spec/unit/bunny_spec.rb 

An error occurred while loading ./spec/unit/bunny_spec.rb.
Failure/Error: TLSv1_3: OpenSSL::SSL::TLS1_3_VERSION,

NameError:
  uninitialized constant OpenSSL::SSL::TLS1_3_VERSION
  Did you mean?  OpenSSL::SSL::TLS1_1_VERSION
                 OpenSSL::SSL::TLS1_2_VERSION
                 OpenSSL::SSL::TLS1_VERSION
                 OpenSSL::SSL::SSL3_VERSION
# ./lib/bunny/transport.rb:34:in `<class:Transport>'

[michaelklishin]

@tindron good catch. I've removed them. Please try again?

[tindron]

@tindron good catch. I've removed them. Please try again?

Looks good! 👍

[dup2]

Thanks for this 👍

[michaelklishin]

Out in 2.20.3.