feat: Define equality methods for LDContext and Reference (#232)

Author: keelerm84

contract-tests/client_entity.rb

@@ -144,6 +144,45 @@ def migration_operation(params)
     end
   end
 
+  def context_comparison(params)
+    context1 = build_context_from_params(params[:context1])
+    context2 = build_context_from_params(params[:context2])
+
+    context1 == context2
+  end
+
+  private def build_context_from_params(params)
+    return build_single_context_from_attribute_definitions(params[:single]) unless params[:single].nil?
+
+    contexts = params[:multi].map do |param|
+      build_single_context_from_attribute_definitions(param)
+    end
+
+    LaunchDarkly::LDContext.create_multi(contexts)
+  end
+
+  private def build_single_context_from_attribute_definitions(params)
+    context = {kind: params[:kind], key: params[:key]}
+
+    params[:attributes]&.each do |attribute|
+      context[attribute[:name]] = attribute[:value]
+    end
+
+    if params[:privateAttributes]
+      context[:_meta] = {
+        privateAttributes: params[:privateAttributes].map do |attribute|
+          if attribute[:literal]
+            LaunchDarkly::Reference.create_literal(attribute[:value])
+          else
+            LaunchDarkly::Reference.create(attribute[:value])
+          end
+        end,
+      }
+    end
+
+    LaunchDarkly::LDContext.create(context)
+  end
+
   def secure_mode_hash(params)
     @client.secure_mode_hash(params[:context])
   end

contract-tests/service.rb

@@ -35,6 +35,7 @@
       'tags',
       'migrations',
       'event-sampling',
+      'context-comparison',
     ],
   }.to_json
 end
@@ -109,6 +110,9 @@
   when "migrationOperation"
     response = {:result => client.migration_operation(params[:migrationOperation]).to_s}
     return [200, nil, response.to_json]
+  when "contextComparison"
+    response = {:equals => client.context_comparison(params[:contextComparison])}
+    return [200, nil, response.to_json]
   end
 
   return [400, nil, {:error => "Unknown command requested"}.to_json]

lib/ldclient-rb/context.rb

@@ -47,9 +47,6 @@ class LDContext
     # @return [String, nil] Returns the error associated with this LDContext if invalid
     attr_reader :error
 
-    # @return [Array<Reference>] Returns the private attributes associated with this LDContext
-    attr_reader :private_attributes
-
     #
     # @private
     # @param key [String, nil]
@@ -69,17 +66,27 @@ def initialize(key, fully_qualified_key, kind, name = nil, anonymous = nil, attr
       @name = name
       @anonymous = anonymous || false
       @attributes = attributes
-      @private_attributes = []
+      @private_attributes = Set.new
       (private_attributes || []).each do |attribute|
         reference = Reference.create(attribute)
-        @private_attributes << reference if reference.error.nil?
+        @private_attributes.add(reference) if reference.error.nil?
       end
       @error = error
       @contexts = contexts
       @is_multi = !contexts.nil?
     end
     private_class_method :new
 
+    protected attr_reader :name, :anonymous, :attributes
+
+    #
+    # @return [Array<Reference>] Returns the private attributes associated with this LDContext
+    #
+    def private_attributes
+      # TODO(sc-227265): Return a set instead of an array.
+      @private_attributes.to_a
+    end
+
     #
     # @return [Boolean] Is this LDContext a multi-kind context?
     #
@@ -274,6 +281,33 @@ def individual_context(kind)
       nil
     end
 
+    def ==(other)
+      return false unless self.kind == other.kind
+      return false unless self.valid? == other.valid?
+      return false unless self.error == other.error
+
+      return false unless self.individual_context_count == other.individual_context_count
+
+      if self.multi_kind?
+        self.kinds.each do |kind|
+          return false unless self.individual_context(kind) == other.individual_context(kind)
+        end
+
+        return true
+      end
+
+      return false unless self.key == other.key
+      return false unless self.name == other.name
+      return false unless self.anonymous == other.anonymous
+      return false unless self.attributes == other.attributes
+
+      # TODO(sc-227265): Calling .to_set is unnecessary once private_attributes are sets.
+      return false unless self.private_attributes.to_set == other.private_attributes.to_set
+
+      true
+    end
+    alias eql? ==
+
     #
     # Retrieve the value of any top level, addressable attribute.
     #

lib/ldclient-rb/impl/context_filter.rb

@@ -142,4 +142,4 @@ def filter(context)
       end
     end
   end
-end
+end

lib/ldclient-rb/reference.rb

@@ -109,6 +109,8 @@ def initialize(raw_path, components = [], error = nil)
     end
     private_class_method :new
 
+    protected attr_reader :components
+
     #
     # Creates a Reference from a string. For the supported syntax and examples,
     # see comments on the Reference type.
@@ -227,6 +229,15 @@ def component(index)
       @components[index]
     end
 
+    def ==(other)
+      self.error == other.error && self.components == other.components
+    end
+    alias eql? ==
+
+    def hash
+      ([error] + components).hash
+    end
+
     #
     # Performs unescaping of attribute reference path components:
     #

spec/context_spec.rb

@@ -296,5 +296,68 @@ module LaunchDarkly
         end
       end
     end
+
+    describe "equality comparisons" do
+      it "single kind contexts are equal" do
+        original_context = subject.create(
+          { key: 'context-key', kind: 'user', name: 'Example name', groups: ['test', 'it', 'here'], address: {street: '123 Easy St', city: 'Every Town'},
+            _meta: { privateAttributes: ['name', 'out of order attribute'] }
+          })
+        duplicate_context = subject.create(
+          { key: 'context-key', kind: 'user', name: 'Example name', groups: ['test', 'it', 'here'], address: {street: '123 Easy St', city: 'Every Town'},
+            _meta: { privateAttributes: ['out of order attribute', 'name'] }
+          })
+        expect(original_context).to eq(duplicate_context)
+      end
+
+      it "multi kind contexts are equal" do
+        org_context = subject.create({ key: 'org-key', kind: 'org' })
+        user_context = subject.create({ key: 'user-key', kind: 'user' })
+        device_context = subject.create({ key: 'device-key', kind: 'device' })
+
+        original_context = subject.create_multi([org_context, user_context])
+        duplicate_context = subject.create_multi([user_context, org_context])
+
+        expect(original_context).to eq(duplicate_context)
+
+        superset_context = subject.create_multi([org_context, user_context, device_context])
+        expect(superset_context).not_to eq(duplicate_context)
+      end
+
+      it "mixed size contexts are not equal" do
+        org_context = subject.create({ key: 'org-key', kind: 'org' })
+        user_context = subject.create({ key: 'user-key', kind: 'user' })
+
+        flattened_multi = subject.create_multi([org_context])
+
+        expect(flattened_multi).to eq(org_context)
+
+        multi = subject.create_multi([org_context, user_context])
+        expect(multi).not_to eq(org_context)
+        expect(multi).not_to eq(user_context)
+      end
+
+      it "failed contexts can be equal" do
+        invalid_hash = subject.create(true)
+        invalid_kind = subject.create({ kind: 'this is not valid' })
+        invalid_key = subject.create({ key: nil })
+        invalid_name = subject.create({ key: 'user-key', name: true })
+        invalid_anonymous = subject.create({ key: 'user-key', anonymous: 'this is no boolean' })
+        invalid_private_attributes = subject.create({ key: 'user-key', _meta: { privateAttributes: 'this is no array' }})
+
+        expect(invalid_hash).not_to eq(invalid_kind)
+        expect(invalid_hash).not_to eq(invalid_key)
+        expect(invalid_hash).not_to eq(invalid_name)
+        expect(invalid_hash).not_to eq(invalid_anonymous)
+        expect(invalid_hash).not_to eq(invalid_private_attributes)
+
+        expect(invalid_hash).to eq(subject.create(true))
+        expect(invalid_kind).to eq(subject.create({ kind: 'this is not valid' }))
+        expect(invalid_key).to eq(subject.create({ key: nil }))
+        expect(invalid_name).to eq(subject.create({ key: 'user-key', name: true }))
+        expect(invalid_anonymous).to eq(subject.create({ key: 'user-key', anonymous: 'this is no boolean' }))
+        expect(invalid_private_attributes).to eq(subject.create({ key: 'user-key', _meta: { privateAttributes: 'this is no array' }}))
+      end
+    end
   end
 end