Livecheck::Options: Add #merge!

Library/Homebrew/livecheck/options.rb

@@ -56,6 +56,33 @@ module Homebrew
         Options.new(**new_options)
       end
 
+      # Merges values from `other` into `self` and returns `self`.
+      #
+      # `nil` values are removed from `other` before merging if it is an
+      # `Options` object, as these are unitiailized values. This ensures that
+      # existing values in `self` aren't unexpectedly overwritten with defaults.
+      sig { params(other: T.any(Options, T::Hash[Symbol, T.untyped])).returns(Options) }
+      def merge!(other)
+        return self if other.empty?
+
+        if other.is_a?(Options)
+          return self if self == other
+
+          other.instance_variables.each do |ivar|
+            next if (v = T.let(other.instance_variable_get(ivar), Object)).nil?
+
+            instance_variable_set(ivar, v)
+          end
+        else
+          other.each do |k, v|
+            cmd = :"#{k}="
+            send(cmd, v) if respond_to?(cmd)
+          end
+        end
+
+        self
+      end
+
       sig { params(other: Object).returns(T::Boolean) }
       def ==(other)
         return false unless other.is_a?(Options)

Library/Homebrew/test/livecheck/options_spec.rb

@@ -27,6 +27,10 @@ RSpec.describe Homebrew::Livecheck::Options do
   end
   let(:merged_hash) { args.merge(other_args) }
 
+  let(:base_options) { options.new(**args) }
+  let(:other_options) { options.new(**other_args) }
+  let(:merged_options) { options.new(**merged_hash) }
+
   describe "#url_options" do
     it "returns a Hash of the options that are provided as arguments to the `url` DSL method" do
       expect(options.new.url_options).to eq({
@@ -68,6 +72,40 @@ RSpec.describe Homebrew::Livecheck::Options do
     end
   end
 
+  describe "#merge!" do
+    it "merges values from `other` into `self` and returns `self`" do
+      o1 = options.new(**args)
+      expect(o1.merge!(other_options)).to eq(merged_options)
+      expect(o1).to eq(merged_options)
+
+      o2 = options.new(**args)
+      expect(o2.merge!(other_args)).to eq(merged_options)
+      expect(o2).to eq(merged_options)
+
+      o3 = options.new(**args)
+      expect(o3.merge!(base_options)).to eq(base_options)
+      expect(o3).to eq(base_options)
+
+      o4 = options.new(**args)
+      expect(o4.merge!(args)).to eq(base_options)
+      expect(o4).to eq(base_options)
+
+      o5 = options.new(**args)
+      expect(o5.merge!(options.new)).to eq(base_options)
+      expect(o5).to eq(base_options)
+
+      o6 = options.new(**args)
+      expect(o6.merge!({})).to eq(base_options)
+      expect(o6).to eq(base_options)
+    end
+
+    it "skips over hash values without a corresponding Options value" do
+      o1 = options.new(**args)
+      expect(o1.merge!({ nonexistent: true })).to eq(base_options)
+      expect(o1).to eq(base_options)
+    end
+  end
+
   describe "#==" do
     it "returns true if all instance variables are the same" do
       obj_with_args1 = options.new(**args)