require Ruby 2.6 or laterky/require-ruby-2.6

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.

7 files changed, 7 insertions, 51 deletions

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f5b6bd92..bfb77536 100644
--- a/.github/workflows/test.yml
+++ b/.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
diff --git a/ext/openssl/ossl.h b/ext/openssl/ossl.h
index 65d022c7..be9dcbdf 100644
--- a/ext/openssl/ossl.h
+++ b/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"
diff --git a/ext/openssl/ossl_pkey_ec.c b/ext/openssl/ossl_pkey_ec.c
index a4a61436..47de7ccd 100644
--- a/ext/openssl/ossl_pkey_ec.c
+++ b/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;
 
diff --git a/ext/openssl/ruby_missing.h b/ext/openssl/ruby_missing.h
deleted file mode 100644
index 069acc8b..00000000
--- a/ext/openssl/ruby_missing.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * 'OpenSSL for Ruby' project
- * Copyright (C) 2001-2003  Michal Rokos <m.rokos@sh.cvut.cz>
- * All rights reserved.
- */
-/*
- * This program is licensed under the same licence as Ruby.
- * (See the file 'LICENCE'.)
- */
-#if !defined(_OSSL_RUBY_MISSING_H_)
-#define _OSSL_RUBY_MISSING_H_
-
-/* Ruby 2.4 */
-#ifndef RB_INTEGER_TYPE_P
-# define RB_INTEGER_TYPE_P(obj) (RB_FIXNUM_P(obj) || RB_TYPE_P(obj, T_BIGNUM))
-#endif
-
-/* Ruby 2.5 */
-#ifndef ST2FIX
-# define RB_ST2FIX(h) LONG2FIX((long)(h))
-# define ST2FIX(h) RB_ST2FIX(h)
-#endif
-
-#endif /* _OSSL_RUBY_MISSING_H_ */
diff --git a/lib/openssl/buffering.rb b/lib/openssl/buffering.rb
index 116179d2..d47e1082 100644
--- a/lib/openssl/buffering.rb
+++ b/lib/openssl/buffering.rb
@@ -99,16 +99,6 @@ module OpenSSL::Buffering
     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 @@ module OpenSSL::Buffering
   # 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
 
   ##
diff --git a/openssl.gemspec b/openssl.gemspec
index e9fd351a..38bcb9db 100644
--- a/openssl.gemspec
+++ b/openssl.gemspec
@@ -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
diff --git a/test/openssl/utils.rb b/test/openssl/utils.rb
index ab5fab4b..85b771dc 100644
--- a/test/openssl/utils.rb
+++ b/test/openssl/utils.rb
@@ -236,9 +236,7 @@ class OpenSSL::SSLTestCase < OpenSSL::TestCase
       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 @@ class OpenSSL::SSLTestCase < OpenSSL::TestCase
               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 @@ class OpenSSL::SSLTestCase < OpenSSL::TestCase
         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)