Promote yaml to default gems

doc/maintainers.rdoc

@@ -103,8 +103,6 @@ Zachary Scott (zzak)
   YAMADA, Akira (akira)
 [lib/weakref.rb]
   _unmaintained_
-[lib/yaml.rb, lib/yaml/*]
-  Aaron Patterson (tenderlove), Hiroshi SHIBATA (hsbt)
 
 === Extensions
 
@@ -269,6 +267,9 @@ Zachary Scott (zzak)
   Eric Wong (normalperson)
   https://bugs.ruby-lang.org/
   https://rubygems.org/gems/webrick
+[lib/yaml.rb, lib/yaml/*]
+  Aaron Patterson (tenderlove), Hiroshi SHIBATA (hsbt)
+  https://github.com/ruby/yaml
 
 === Extensions
 

doc/standard_library.rdoc

@@ -39,7 +39,6 @@ TSort:: Topological sorting using Tarjan's algorithm
 un.rb:: Utilities to replace common UNIX commands
 URI:: A Ruby module providing support for Uniform Resource Identifiers
 WeakRef:: Allows a referenced object to be garbage-collected
-YAML:: Ruby client library for the Psych YAML implementation
 
 == Extensions
 
@@ -88,6 +87,7 @@ Singleton:: Implementation of the Singleton pattern for Ruby
 Timeout:: Auto-terminate potentially long-running operations in Ruby
 Tracer:: Outputs a source level execution trace of a Ruby program
 WEBrick:: An HTTP server toolkit for Ruby
+YAML:: Ruby client library for the Psych YAML implementation
 
 == Extensions
 

lib/yaml/version.rb

@@ -0,0 +1,3 @@
+module YAML
+  VERSION = "0.1.0"
+end

lib/yaml/yaml.gemspec

@@ -0,0 +1,29 @@
+begin
+  require_relative "lib/yaml/version"
+rescue LoadError # Fallback to load version file in ruby core repository
+  require_relative "version"
+end
+
+Gem::Specification.new do |spec|
+  spec.name          = "yaml"
+  spec.version       = YAML::VERSION
+  spec.authors       = ["Aaron Patterson", "SHIBATA Hiroshi"]
+  spec.email         = ["aaron@tenderlovemaking.com", "hsbt@ruby-lang.org"]
+
+  spec.summary       = "YAML Ain't Markup Language"
+  spec.description   = spec.summary
+  spec.homepage      = "https://github.com/ruby/yaml"
+  spec.license       = "BSD-2-Clause"
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
+    `git ls-files -z`.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) }
+  spec.require_paths = ["lib"]
+end

tool/sync_default_gems.rb

@@ -46,6 +46,7 @@
 # * https://github.com/ruby/readline-ext
 # * https://github.com/ruby/observer
 # * https://github.com/ruby/timeout
+# * https://github.com/ruby/yaml
 #
 
 require 'fileutils'
@@ -99,6 +100,7 @@ $repositories = {
   readlineext: "ruby/readline-ext",
   observer: "ruby/observer",
   timeout: "ruby/timeout",
+  yaml: "ruby/yaml",
 }
 
 def sync_default_gems(gem)