Improve Array.wrap in ActiveSupport (#683)

* Improve Array.wrap in ActiveSupport

* move signature to more generic file

gems/activesupport/6.0/_test/test.rb

@@ -70,3 +70,8 @@ class TestAttrInternal
 "Matz".presence_in("Matzuyama")&.in?(%w[Yukihiro Matz Matsumoto])
 ActiveSupport::TimeZone['Asia/Tokyo'].to_s
 Time.find_zone(Object.name)
+
+Array.wrap(nil)
+Array.wrap([1, 2, 3])
+Array.wrap("hello")
+Array.wrap({a: 1, b: 2})

gems/activesupport/6.0/activesupport-generated.rbs

@@ -2138,45 +2138,6 @@ class Array[unchecked out Elem]
   def inquiry: () -> ActiveSupport::ArrayInquirer[Elem]
 end
 
-class Array[unchecked out Elem]
-  # Wraps its argument in an array unless it is already an array (or array-like).
-  #
-  # Specifically:
-  #
-  # * If the argument is +nil+ an empty array is returned.
-  # * Otherwise, if the argument responds to +to_ary+ it is invoked, and its result returned.
-  # * Otherwise, returns an array with the argument as its single element.
-  #
-  #     Array.wrap(nil)       # => []
-  #     Array.wrap([1, 2, 3]) # => [1, 2, 3]
-  #     Array.wrap(0)         # => [0]
-  #
-  # This method is similar in purpose to <tt>Kernel#Array</tt>, but there are some differences:
-  #
-  # * If the argument responds to +to_ary+ the method is invoked. <tt>Kernel#Array</tt>
-  #   moves on to try +to_a+ if the returned value is +nil+, but <tt>Array.wrap</tt> returns
-  #   an array with the argument as its single element right away.
-  # * If the returned value from +to_ary+ is neither +nil+ nor an +Array+ object, <tt>Kernel#Array</tt>
-  #   raises an exception, while <tt>Array.wrap</tt> does not, it just returns the value.
-  # * It does not call +to_a+ on the argument, if the argument does not respond to +to_ary+
-  #   it returns an array with the argument as its single element.
-  #
-  # The last point is easily explained with some enumerables:
-  #
-  #   Array(foo: :bar)      # => [[:foo, :bar]]
-  #   Array.wrap(foo: :bar) # => [{:foo=>:bar}]
-  #
-  # There's also a related idiom that uses the splat operator:
-  #
-  #   [*object]
-  #
-  # which returns <tt>[]</tt> for +nil+, but calls to <tt>Array(object)</tt> otherwise.
-  #
-  # The differences with <tt>Kernel#Array</tt> explained above
-  # apply to the rest of <tt>object</tt>s.
-  def self.wrap: (untyped object) -> untyped
-end
-
 module ActiveSupport
   module BigDecimalWithDefaultFormat
     # nodoc:

gems/activesupport/6.0/activesupport.rbs

@@ -465,6 +465,47 @@ class String
   def foreign_key: (?boolish separate_class_name_and_id_with_underscore) -> String
 end
 
+class Array[unchecked out Elem]
+  # Wraps its argument in an array unless it is already an array (or array-like).
+  #
+  # Specifically:
+  #
+  # * If the argument is +nil+ an empty array is returned.
+  # * Otherwise, if the argument responds to +to_ary+ it is invoked, and its result returned.
+  # * Otherwise, returns an array with the argument as its single element.
+  #
+  #     Array.wrap(nil)       # => []
+  #     Array.wrap([1, 2, 3]) # => [1, 2, 3]
+  #     Array.wrap(0)         # => [0]
+  #
+  # This method is similar in purpose to <tt>Kernel#Array</tt>, but there are some differences:
+  #
+  # * If the argument responds to +to_ary+ the method is invoked. <tt>Kernel#Array</tt>
+  #   moves on to try +to_a+ if the returned value is +nil+, but <tt>Array.wrap</tt> returns
+  #   an array with the argument as its single element right away.
+  # * If the returned value from +to_ary+ is neither +nil+ nor an +Array+ object, <tt>Kernel#Array</tt>
+  #   raises an exception, while <tt>Array.wrap</tt> does not, it just returns the value.
+  # * It does not call +to_a+ on the argument, if the argument does not respond to +to_ary+
+  #   it returns an array with the argument as its single element.
+  #
+  # The last point is easily explained with some enumerables:
+  #
+  #   Array(foo: :bar)      # => [[:foo, :bar]]
+  #   Array.wrap(foo: :bar) # => [{:foo=>:bar}]
+  #
+  # There's also a related idiom that uses the splat operator:
+  #
+  #   [*object]
+  #
+  # which returns <tt>[]</tt> for +nil+, but calls to <tt>Array(object)</tt> otherwise.
+  #
+  # The differences with <tt>Kernel#Array</tt> explained above
+  # apply to the rest of <tt>object</tt>s.
+  def self.wrap: (nil) -> []
+               | [T] (_ToAry[T] array_like) -> Array[T]
+               | [T] (T ele) -> [T]
+end
+
 module ActiveSupport
   # Rescuable module adds support for easier exception handling.
   module Rescuable

gems/activesupport/7.0/_test/test.rb

@@ -22,3 +22,8 @@
 ActiveSupport::TimeZone['Asia/Tokyo'].to_s
 Time.find_zone(Object.name)
 Time.zone.now.to_fs
+
+Array.wrap(nil)
+Array.wrap([1, 2, 3])
+Array.wrap("hello")
+Array.wrap({a: 1, b: 2})