Merge branch 'master' into master

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      interval: 'weekly'

.github/workflows/test.yml

@@ -3,15 +3,21 @@ name: test
 on: [push, pull_request]
 
 jobs:
-  build:
+  ruby-versions:
+    uses: ruby/actions/.github/workflows/ruby_versions.yml@master
+    with:
+      engine: cruby
+      min_version: 2.4
+  test:
+    needs: ruby-versions
     name: build (${{ matrix.ruby }} / ${{ matrix.os }})
     strategy:
       matrix:
-        ruby: [ 2.7, 2.6, 2.5, 2.4, head ]
+        ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
         os: [ ubuntu-latest, macos-latest ]
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:

LICENSE.txt → BSDL

@@ -4,10 +4,10 @@ Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 1. Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
+   notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
-notice, this list of conditions and the following disclaimer in the
-documentation and/or other materials provided with the distribution.
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
 
 THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

COPYING

@@ -0,0 +1,56 @@
+Ruby is copyrighted free software by Yukihiro Matsumoto <[email protected]>.
+You can redistribute it and/or modify it under either the terms of the
+2-clause BSDL (see the file BSDL), or the conditions below:
+
+1. You may make and give away verbatim copies of the source form of the
+   software without restriction, provided that you duplicate all of the
+   original copyright notices and associated disclaimers.
+
+2. You may modify your copy of the software in any way, provided that
+   you do at least ONE of the following:
+
+   a. place your modifications in the Public Domain or otherwise
+      make them Freely Available, such as by posting said
+      modifications to Usenet or an equivalent medium, or by allowing
+      the author to include your modifications in the software.
+
+   b. use the modified software only within your corporation or
+      organization.
+
+   c. give non-standard binaries non-standard names, with
+      instructions on where to get the original software distribution.
+
+   d. make other distribution arrangements with the author.
+
+3. You may distribute the software in object code or binary form,
+   provided that you do at least ONE of the following:
+
+   a. distribute the binaries and library files of the software,
+      together with instructions (in the manual page or equivalent)
+      on where to get the original distribution.
+
+   b. accompany the distribution with the machine-readable source of
+      the software.
+
+   c. give non-standard binaries non-standard names, with
+      instructions on where to get the original software distribution.
+
+   d. make other distribution arrangements with the author.
+
+4. You may modify and include the part of the software into any other
+   software (possibly commercial).  But some files in the distribution
+   are not written by the author, so that they are not under these terms.
+
+   For the list of those files and their copying conditions, see the
+   file LEGAL.
+
+5. The scripts and library files supplied as input to or produced as
+   output from the software do not automatically fall under the
+   copyright of the software, but belong to whomever generated them,
+   and may be sold commercially, and may be aggregated with this
+   software.
+
+6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+   IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+   PURPOSE.

lib/singleton.rb

@@ -92,7 +92,7 @@
 #    p a.strip #  => nil
 #
 module Singleton
-  VERSION = "0.1.1"
+  VERSION = "0.2.0"
 
   module SingletonInstanceMethods
     # Raises a TypeError to prevent cloning.
@@ -124,12 +124,7 @@ def _load(str)
     end
 
     def instance # :nodoc:
-      return @singleton__instance__ if @singleton__instance__
-      @singleton__mutex__.synchronize {
-        return @singleton__instance__ if @singleton__instance__
-        set_instance(new())
-      }
-      @singleton__instance__
+      @singleton__instance__ || @singleton__mutex__.synchronize { @singleton__instance__ ||= set_instance(new) }
     end
 
     private

singleton.gemspec

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 name = File.basename(__FILE__, ".gemspec")
-version = ["lib", Array.new(name.count("-")+1, "..").join("/")].find do |dir|
+version = ["lib", Array.new(name.count("-")+1, ".").join("/")].find do |dir|
   break File.foreach(File.join(__dir__, dir, "#{name.tr('-', '/')}.rb")) do |line|
     /^\s*VERSION\s*=\s*"(.*)"/ =~ line and break $1
   end rescue nil
@@ -22,7 +22,7 @@ Gem::Specification.new do |spec|
   spec.metadata["source_code_uri"] = spec.homepage
 
   spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
-    `git ls-files -z 2>/dev/null`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+    `git ls-files -z 2>#{IO::NULL}`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
   end
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }

test/test_singleton.rb

@@ -94,11 +94,32 @@ def test_inheritance_works_with_overridden_inherited_method
     assert_same a, b
   end
 
+  def test_inheritance_creates_separate_singleton
+    a = SingletonTest.instance
+    b = Class.new(SingletonTest).instance
+
+    assert_not_same a, b
+  end
+
+  def test_inheritance_instantiation
+    klass = Class.new do
+      include Singleton
+
+      public_class_method :new
+    end
+
+    assert Class.new(klass).new
+  end
+
   def test_class_level_cloning_preserves_singleton_behavior
     klass = SingletonTest.clone
 
     a = klass.instance
     b = klass.instance
     assert_same a, b
   end
+
+  def test_class_level_cloning_creates_separate_singleton
+    assert_not_same SingletonTest.instance, SingletonTest.clone.instance
+  end
 end