[Feature #18595] Alias String#-@ as String#dedup

Merged: https://github.com/ruby/ruby/pull/5583

spec/ruby/core/string/dedup_spec.rb

@@ -0,0 +1,8 @@
+require_relative '../../spec_helper'
+require_relative 'shared/dedup'
+
+describe 'String#dedup' do
+  ruby_version_is '3.2'do
+    it_behaves_like :string_dedup, :dedup
+  end
+end

spec/ruby/core/string/shared/dedup.rb

@@ -0,0 +1,47 @@
+describe :string_dedup, shared: true do
+  it 'returns self if the String is frozen' do
+    input  = 'foo'.freeze
+    output = input.send(@method)
+
+    output.should equal(input)
+    output.should.frozen?
+  end
+
+  it 'returns a frozen copy if the String is not frozen' do
+    input  = 'foo'
+    output = input.send(@method)
+
+    output.should.frozen?
+    output.should_not equal(input)
+    output.should == 'foo'
+  end
+
+  it "returns the same object for equal unfrozen strings" do
+    origin = "this is a string"
+    dynamic = %w(this is a string).join(' ')
+
+    origin.should_not equal(dynamic)
+    origin.send(@method).should equal(dynamic.send(@method))
+  end
+
+  it "returns the same object when it's called on the same String literal" do
+    "unfrozen string".send(@method).should equal("unfrozen string".send(@method))
+    "unfrozen string".send(@method).should_not equal("another unfrozen string".send(@method))
+  end
+
+  it "deduplicates frozen strings" do
+    dynamic = %w(this string is frozen).join(' ').freeze
+
+    dynamic.should_not equal("this string is frozen".freeze)
+
+    dynamic.send(@method).should equal("this string is frozen".freeze)
+    dynamic.send(@method).should equal("this string is frozen".send(@method).freeze)
+  end
+
+  ruby_version_is "3.0" do
+    it "interns the provided string if it is frozen" do
+      dynamic = "this string is unique and frozen #{rand}".freeze
+      dynamic.send(@method).should equal(dynamic)
+    end
+  end
+end

spec/ruby/core/string/uminus_spec.rb

@@ -1,49 +1,6 @@
 require_relative '../../spec_helper'
+require_relative 'shared/dedup'
 
 describe 'String#-@' do
-  it 'returns self if the String is frozen' do
-    input  = 'foo'.freeze
-    output = -input
-
-    output.should equal(input)
-    output.should.frozen?
-  end
-
-  it 'returns a frozen copy if the String is not frozen' do
-    input  = 'foo'
-    output = -input
-
-    output.should.frozen?
-    output.should_not equal(input)
-    output.should == 'foo'
-  end
-
-  it "returns the same object for equal unfrozen strings" do
-    origin = "this is a string"
-    dynamic = %w(this is a string).join(' ')
-
-    origin.should_not equal(dynamic)
-    (-origin).should equal(-dynamic)
-  end
-
-  it "returns the same object when it's called on the same String literal" do
-    (-"unfrozen string").should equal(-"unfrozen string")
-    (-"unfrozen string").should_not equal(-"another unfrozen string")
-  end
-
-  it "deduplicates frozen strings" do
-    dynamic = %w(this string is frozen).join(' ').freeze
-
-    dynamic.should_not equal("this string is frozen".freeze)
-
-    (-dynamic).should equal("this string is frozen".freeze)
-    (-dynamic).should equal(-"this string is frozen".freeze)
-  end
-
-  ruby_version_is "3.0" do
-    it "interns the provided string if it is frozen" do
-      dynamic = "this string is unique and frozen #{rand}".freeze
-      (-dynamic).should equal(dynamic)
-    end
-  end
+  it_behaves_like :string_dedup, :-@
 end

string.c

@@ -2933,7 +2933,9 @@ str_uplus(VALUE str)
  * Returns a frozen, possibly pre-existing copy of the string.
  *
  * The returned \String will be deduplicated as long as it does not have
- * any instance variables set on it.
+ * any instance variables set on it and is not a String subclass.
+ *
+ * String#dedup is an alias for String#-@.
  */
 static VALUE
 str_uminus(VALUE str)
@@ -11879,6 +11881,7 @@ Init_String(void)
     rb_define_method(rb_cString, "freeze", rb_str_freeze, 0);
     rb_define_method(rb_cString, "+@", str_uplus, 0);
     rb_define_method(rb_cString, "-@", str_uminus, 0);
+    rb_define_alias(rb_cString, "dedup", "-@");
 
     rb_define_method(rb_cString, "to_i", rb_str_to_i, -1);
     rb_define_method(rb_cString, "to_f", rb_str_to_f, 0);