1 files changed, 71 insertions, 0 deletions
diff --git a/spec/ruby/command_line/feature_spec.rb b/spec/ruby/command_line/feature_spec.rb
new file mode 100644
index 0000000000..838581d04a
--- /dev/null
+++ b/spec/ruby/command_line/feature_spec.rb
@@ -0,0 +1,71 @@
+require_relative '../spec_helper'
+
+describe "The --enable and --disable flags" do
+  before :all do
+    # Since some specs disable reading RUBYOPT, we instead pass its contents as :options for those specs
+    rubyopt = [ENV["RUBYOPT"]]
+    rubyopt << ENV["#{RUBY_ENGINE.upcase}OPT"] unless RUBY_ENGINE == 'ruby'
+    @rubyopt = RUBY_ENGINE == "ruby" ? "" : rubyopt.compact.join(" ")
+  end
+
+  it "can be used with gems" do
+    ruby_exe("p defined?(Gem)", options: "--enable=gems").chomp.should == "\"constant\""
+    ruby_exe("p defined?(Gem)", options: "--disable=gems").chomp.should == "nil"
+    ruby_exe("p defined?(Gem)", options: "--enable-gems").chomp.should == "\"constant\""
+    ruby_exe("p defined?(Gem)", options: "--disable-gems").chomp.should == "nil"
+  end
+
+  it "can be used with gem" do
+    ruby_exe("p defined?(Gem)", options: "--enable=gem").chomp.should == "\"constant\""
+    ruby_exe("p defined?(Gem)", options: "--disable=gem").chomp.should == "nil"
+    ruby_exe("p defined?(Gem)", options: "--enable-gem").chomp.should == "\"constant\""
+    ruby_exe("p defined?(Gem)", options: "--disable-gem").chomp.should == "nil"
+  end
+
+  it "can be used with did_you_mean" do
+    ruby_exe("p defined?(DidYouMean)", options: "--enable=did_you_mean").chomp.should == "\"constant\""
+    ruby_exe("p defined?(DidYouMean)", options: "--disable=did_you_mean").chomp.should == "nil"
+    ruby_exe("p defined?(DidYouMean)", options: "--enable-did_you_mean").chomp.should == "\"constant\""
+    ruby_exe("p defined?(DidYouMean)", options: "--disable-did_you_mean").chomp.should == "nil"
+  end
+
+  it "can be used with rubyopt" do
+    ruby_exe("p $VERBOSE", options: "--enable=rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "true"
+    ruby_exe("p $VERBOSE", options: "#{@rubyopt} --disable=rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "false"
+    ruby_exe("p $VERBOSE", options: "--enable-rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "true"
+    ruby_exe("p $VERBOSE", options: "#{@rubyopt} --disable-rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "false"
+  end
+
+  it "can be used with frozen-string-literal" do
+    ruby_exe("p 'foo'.frozen?", options: "--enable=frozen-string-literal").chomp.should == "true"
+    ruby_exe("p 'foo'.frozen?", options: "--disable=frozen-string-literal").chomp.should == "false"
+    ruby_exe("p 'foo'.frozen?", options: "--enable-frozen-string-literal").chomp.should == "true"
+    ruby_exe("p 'foo'.frozen?", options: "--disable-frozen-string-literal").chomp.should == "false"
+  end
+
+  # frequently hangs for >60s on GitHub Actions macos-latest
+  # MinGW's YJIT support seems broken
+  platform_is_not :darwin, :mingw do
+    it "can be used with all for enable" do
+      e = "p [defined?(Gem), defined?(DidYouMean), $VERBOSE, 'foo'.frozen?]"
+      env = {'RUBYOPT' => '-w'}
+      # Use a single variant here because it can be quite slow as it might enable jit, etc
+      ruby_exe(e, options: "--enable-all", env: env).chomp.should == "[\"constant\", \"constant\", true, true]"
+    end unless defined?(RubyVM::YJIT) && defined?(RubyVM::ZJIT) && RubyVM::ZJIT.enabled? # You're not supposed to enable YJIT with --enable-all when ZJIT options are passed.
+  end
+
+  it "can be used with all for disable" do
+    e = "p [defined?(Gem), defined?(DidYouMean), $VERBOSE, 'foo'.frozen?]"
+    env = {'RUBYOPT' => '-w'}
+    ruby_exe(e, options: "#{@rubyopt} --disable=all", env: env).chomp.should == "[nil, nil, false, false]"
+    ruby_exe(e, options: "#{@rubyopt} --disable-all", env: env).chomp.should == "[nil, nil, false, false]"
+  end
+
+  it "prints a warning for unknown features" do
+    ruby_exe("p 14", options: "--enable=ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --enable')
+    ruby_exe("p 14", options: "--disable=ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --disable')
+    ruby_exe("p 14", options: "--enable-ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --enable')
+    ruby_exe("p 14", options: "--disable-ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --disable')
+  end
+
+end