Support all cgi.gem versions (#60)

Author: k0kubun

erb.gemspec

@@ -14,7 +14,6 @@ Gem::Specification.new do |spec|
   spec.summary       = %q{An easy to use but powerful templating system for Ruby.}
   spec.description   = %q{An easy to use but powerful templating system for Ruby.}
   spec.homepage      = 'https://github.com/ruby/erb'
-  spec.required_ruby_version = Gem::Requirement.new('>= 2.5.0')
   spec.licenses      = ['Ruby', 'BSD-2-Clause']
 
   spec.metadata['homepage_uri'] = spec.homepage
@@ -27,10 +26,11 @@ Gem::Specification.new do |spec|
   spec.executables   = ['erb']
   spec.require_paths = ['lib']
 
+  spec.required_ruby_version = '>= 3.2.0'
+
   if RUBY_ENGINE == 'jruby'
     spec.platform = 'java'
   else
-    spec.required_ruby_version = '>= 2.7.0'
     spec.extensions = ['ext/erb/escape/extconf.rb']
   end
 end

lib/erb.rb

@@ -12,7 +12,6 @@
 #
 # You can redistribute it and/or modify it under the same terms as Ruby.
 
-require 'cgi/escape'
 require 'erb/version'
 require 'erb/compiler'
 require 'erb/def_method'

lib/erb/util.rb

@@ -1,5 +1,13 @@
 # frozen_string_literal: true
 
+# Load CGI.escapeHTML and CGI.escapeURIComponent.
+# CRuby:
+#   cgi.gem v0.1.0+ (Ruby 2.7-3.4) and Ruby 3.5+ stdlib have 'cgi/escape' and CGI.escapeHTML.
+#   cgi.gem v0.3.3+ (Ruby 3.2-3.4) and Ruby 3.5+ stdlib have CGI.escapeURIComponent.
+# JRuby: cgi.gem has a Java extension 'cgi/escape'.
+# TruffleRuby: lib/truffle/cgi/escape.rb requires 'cgi/util'.
+require 'cgi/escape'
+
 begin
   # We don't build the C extension for JRuby, TruffleRuby, and WASM
   if $LOAD_PATH.resolve_feature_path('erb/escape')
@@ -53,8 +61,16 @@ module ERB::Util
   #
   #   Programming%20Ruby%3A%20%20The%20Pragmatic%20Programmer%27s%20Guide
   #
-  def url_encode(s)
-    CGI.escapeURIComponent(s.to_s)
+  if CGI.respond_to?(:escapeURIComponent)
+    def url_encode(s)
+      CGI.escapeURIComponent(s.to_s)
+    end
+  else # cgi.gem <= v0.3.2
+    def url_encode(s)
+      s.to_s.b.gsub(/[^a-zA-Z0-9_\-.~]/n) do |m|
+        sprintf("%%%02X", m.unpack1("C"))
+      end
+    end
   end
   alias u url_encode
   module_function :u