Fix retaining compare_by_identity flag for Hash methods #select, #slice, #transform_values and Hash[]

Author: andrykonchin

core/hash/compact_spec.rb

@@ -35,7 +35,7 @@
       hash.compact.default_proc.should == pr
     end
 
-    it "retains compare_by_identity_flag" do
+    it "retains compare_by_identity flag" do
       hash = {}.compare_by_identity
       hash.compact.compare_by_identity?.should == true
       hash[:a] = 1

core/hash/constructor_spec.rb

@@ -118,10 +118,11 @@ def obj.to_hash() { 1 => 2, 3 => 4 } end
   end
 
   ruby_version_is '3.3' do
-    it "does not retain compare_by_identity_flag" do
-      hash = {}.compare_by_identity
+    it "does not retain compare_by_identity flag" do
+      hash = { a: 1 }.compare_by_identity
       Hash[hash].compare_by_identity?.should == false
-      hash[:a] = 1
+
+      hash = {}.compare_by_identity
       Hash[hash].compare_by_identity?.should == false
     end
   end

core/hash/except_spec.rb

@@ -29,4 +29,10 @@
     r.class.should == Hash
     r.default.should == nil
   end
+
+  it "retains compare_by_identity flag" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = h.except(:a)
+    h2.compare_by_identity?.should == true
+  end
 end

core/hash/invert_spec.rb

@@ -24,4 +24,10 @@
     HashSpecs::MyHash[1 => 2, 3 => 4].invert.class.should == Hash
     HashSpecs::MyHash[].invert.class.should == Hash
   end
+
+  it "does not retain compare_by_identity flag" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = h.invert
+    h2.compare_by_identity?.should == false
+  end
 end

core/hash/merge_spec.rb

@@ -93,6 +93,18 @@
     merged.should eql(hash)
     merged.should_not equal(hash)
   end
+
+  it "retains compare_by_identity flag" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = h.merge(b: 1, d: 2)
+    h2.compare_by_identity?.should == true
+  end
+
+  it "ignores compare_by_identity flag of an argument" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = { b: 1, d: 2 }.merge(h)
+    h2.compare_by_identity?.should == false
+  end
 end
 
 describe "Hash#merge!" do

core/hash/reject_spec.rb

@@ -44,6 +44,12 @@ def h.to_a() end
     reject_pairs.should == reject_bang_pairs
   end
 
+  it "retains compare_by_identity flag" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = h.reject { |k, _| k == :a }
+    h2.compare_by_identity?.should == true
+  end
+
   it_behaves_like :hash_iteration_no_block, :reject
   it_behaves_like :enumeratorized_with_origin_size, :reject, { 1 => 2, 3 => 4, 5 => 6 }
 end

core/hash/replace_spec.rb

@@ -23,20 +23,17 @@
     h.should == { 1 => 2 }
   end
 
-  it "transfers the compare_by_identity flag" do
-    hash_a = { a: 1 }
-    hash_b = { b: 2 }
-    hash_b.compare_by_identity
-    hash_a.should_not.compare_by_identity?
-    hash_a.replace(hash_b)
-    hash_a.should.compare_by_identity?
+  it "transfers compare_by_identity flag of an argument" do
+    h = { a: 1, c: 3 }
+    h2 = { b: 2, d: 4 }.compare_by_identity
+    h.replace(h2)
+    h.compare_by_identity?.should == true
+  end
 
-    hash_a = { a: 1 }
-    hash_b = { b: 2 }
-    hash_a.compare_by_identity
-    hash_a.should.compare_by_identity?
-    hash_a.replace(hash_b)
-    hash_a.should_not.compare_by_identity?
+  it "does not retain compare_by_identity flag" do
+    h = { a: 1, c: 3 }.compare_by_identity
+    h.replace(b: 2, d: 4)
+    h.compare_by_identity?.should == false
   end
 
   it "does not transfer default values" do

core/hash/shared/select.rb

@@ -40,6 +40,12 @@
     @empty.send(@method).should be_an_instance_of(Enumerator)
   end
 
+  it "retains compare_by_identity flag" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = h.send(@method) { |k, _| k == :a }
+    h2.compare_by_identity?.should == true
+  end
+
   it_should_behave_like :hash_iteration_no_block
 
   before :each do

core/hash/slice_spec.rb

@@ -50,4 +50,10 @@ def [](value)
 
     ScratchPad.recorded.should == []
   end
+
+  it "retains compare_by_identity flag" do
+    h = { a: 9, c: 4 }.compare_by_identity
+    h2 = h.slice(:a)
+    h2.compare_by_identity?.should == true
+  end
 end

core/hash/to_h_spec.rb

@@ -30,6 +30,11 @@
       @h.to_h.default_proc.should == prc
       @h[42].should == 84
     end
+
+    it "retains compare_by_identity flag" do
+      @h.compare_by_identity
+      @h.to_h.compare_by_identity?.should == true
+    end
   end
 
   context "with block" do
@@ -78,5 +83,11 @@
         { a: 1 }.to_h { |k| x }
       end.should raise_error(TypeError, /wrong element type MockObject/)
     end
+
+    it "does not retain compare_by_identity flag" do
+      h = { a: 9, c: 4 }.compare_by_identity
+      h2 = h.to_h { |k, v| [k.to_s, v*v]}
+      h2.compare_by_identity?.should == false
+    end
   end
 end