Kw/object regexp

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## [Unreleased]
 
+- Ruby 3.2+: Add back `Object#=~`
+
 ## [1.3.0] - 2024-04-16
 
 - Ruby 3.2+: Add back third argument to Regexp.new, to allow passing "n" to set `Regexp::NOENCODING`.

README.md

@@ -136,7 +136,9 @@ require 'ruby3_backward_compatibility/compatibility/i18n'
 
 The methods `Object#taint` and `Object#untaint` were no-ops for a while but started to raise deprecation warnings.
 
-To add them back as no-ops, use
+The method `Object#=~` always returned `nil` if called on anything else than a String. It was removed in Ruby 3.2.
+
+To add back `Object#taint` and `Object#untaint` as no-ops and `Object#=~` on arbitrary receivers, use
 
 ```
 require 'ruby3_backward_compatibility/compatibility/object'

lib/ruby3_backward_compatibility/compatibility/object.rb

@@ -8,6 +8,14 @@ def taint
     def untaint
       self
     end
+
+    # Make the match operator work on arbitrary receivers again.
+    def =~(regexp)
+      if Warning[:deprecated]
+        Warning.warn("deprecated Object#=~ is called on #{self.class}; it always returns nil")
+      end
+      nil
+    end
   end
 end
 

spec/ruby3_backward_compatibility/compatibility/object_spec.rb

@@ -15,5 +15,37 @@ module Ruby3BackwardCompatibility
         expect(object.untaint).to eq(object)
       end
     end
+
+    describe '#=~' do
+      it 'returns nil if called on an arbitrary Object' do
+        object = Object.new
+        expect(object =~ /asdf/).to be_nil
+      end
+
+      it 'outputs a deprecation warning if called on an arbitrary Object' do
+        begin
+          Warning[:deprecated] = true
+          hash = {}
+          expect { hash =~ /asdf/ }.to output(/deprecated.*Hash/).to_stderr
+        ensure
+          Warning[:deprecated] = false
+        end
+      end
+
+      it 'still works on String' do
+        string = '-- asdf --'
+        expect(string =~ /asdf/).to eq(3)
+      end
+
+      it "doesn't output a deprecation warning if called on a String" do
+        begin
+          Warning[:deprecated] = true
+          string = '-- asdf --'
+          expect { string =~ /asdf/ }.not_to output(/deprecated/).to_stderr
+        ensure
+          Warning[:deprecated] = false
+        end
+      end
+    end
   end
 end