require Ruby 2.6 or later

Drop support for Ruby 2.3, 2.4, and 2.5.

As of 2021-10, Ruby 2.6 is the oldest version that still receives
security fixes from the Ruby core team, so it doesn't make much sense
to keep code for those ancient versions.

Author: rhenium

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest, macos-latest ]
-        ruby: [ head, "3.0", "2.7", "2.6", "2.5", "2.4", "2.3" ]
+        ruby: [ head, "3.0", "2.7", "2.6" ]
     steps:
       - name: repo checkout
         uses: actions/checkout@v2
@@ -38,7 +38,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ windows-latest ]
-        ruby: [ mswin, mingw, "3.0", "2.7", "2.6", "2.5", "2.4", "2.3" ]
+        ruby: [ mswin, mingw, "3.0", "2.7", "2.6" ]
     steps:
       - name: repo checkout
         uses: actions/checkout@v2

ext/openssl/ossl.h

@@ -155,7 +155,6 @@ void ossl_debug(const char *, ...);
  * Include all parts
  */
 #include "openssl_missing.h"
-#include "ruby_missing.h"
 #include "ossl_asn1.h"
 #include "ossl_bio.h"
 #include "ossl_bn.h"

ext/openssl/ossl_pkey_ec.c

@@ -598,9 +598,6 @@ static VALUE ossl_ec_group_initialize(int argc, VALUE *argv, VALUE self)
         ossl_raise(rb_eArgError, "wrong number of arguments");
     }
 
-#if !defined(LIKELY) && !defined(RB_LIKELY)
-#define LIKELY(x) (x)
-#endif
     ASSUME(group);
     RTYPEDDATA_DATA(self) = group;
 

ext/openssl/ruby_missing.h

@@ -99,16 +99,6 @@ def consume_rbuff(size=nil)
     end
   end
 
-  if "".respond_to?(:unpack1)
-    def unpack_byte(str)
-      str.unpack1("C")
-    end
-  else
-    def unpack_byte(str)
-      str.unpack("C").first
-    end
-  end
-
   public
 
   # call-seq:
@@ -117,7 +107,7 @@ def unpack_byte(str)
   # Get the next 8bit byte from `ssl`.  Returns `nil` on EOF
   def getbyte
     byte = read(1)
-    byte && unpack_byte(byte)
+    byte && byte.unpack1("C")
   end
 
   ##

lib/openssl/buffering.rb

@@ -15,7 +15,7 @@ Gem::Specification.new do |spec|
   spec.extra_rdoc_files = Dir["*.md"]
   spec.rdoc_options = ["--main", "README.md"]
 
-  spec.required_ruby_version = ">= 2.3.0"
+  spec.required_ruby_version = ">= 2.6.0"
 
   spec.metadata["msys2_mingw_dependencies"] = "openssl"
 end

openssl.gemspec

@@ -236,9 +236,7 @@ def start_server(verify_mode: OpenSSL::SSL::VERIFY_NONE, start_immediately: true
       threads = []
       begin
         server_thread = Thread.new do
-          if Thread.method_defined?(:report_on_exception=) # Ruby >= 2.4
-            Thread.current.report_on_exception = false
-          end
+          Thread.current.report_on_exception = false
 
           begin
             loop do
@@ -254,9 +252,7 @@ def start_server(verify_mode: OpenSSL::SSL::VERIFY_NONE, start_immediately: true
               end
 
               th = Thread.new do
-                if Thread.method_defined?(:report_on_exception=)
-                  Thread.current.report_on_exception = false
-                end
+                Thread.current.report_on_exception = false
 
                 begin
                   server_proc.call(ctx, ssl)
@@ -273,9 +269,7 @@ def start_server(verify_mode: OpenSSL::SSL::VERIFY_NONE, start_immediately: true
         end
 
         client_thread = Thread.new do
-          if Thread.method_defined?(:report_on_exception=)
-            Thread.current.report_on_exception = false
-          end
+          Thread.current.report_on_exception = false
 
           begin
             block.call(port)