Fix formatting diffs between two non-custom objects

When comparing different versions of the same non-custom object — that
is, an object which does not have an `attributes_for_super_diff` method
— the way that we present the diff between the two versions needs to
match the way that that object is deep-inspected. This commit fixes this
by splitting Object at each level into CustomObject and DefaultObject.

Author: mcmire

lib/super_diff/active_record/operational_sequencers/active_record_model.rb

@@ -1,7 +1,7 @@
 module SuperDiff
   module ActiveRecord
     module OperationalSequencers
-      class ActiveRecordModel < SuperDiff::OperationalSequencers::Object
+      class ActiveRecordModel < SuperDiff::OperationalSequencers::CustomObject
         def self.applies_to?(expected, actual)
           expected.is_a?(::ActiveRecord::Base) &&
             actual.is_a?(::ActiveRecord::Base) &&
@@ -13,18 +13,6 @@ def self.applies_to?(expected, actual)
         def attribute_names
           ["id"] + (expected.attributes.keys.sort - ["id"])
         end
-
-        private
-
-        def establish_expected_and_actual_attributes
-          @expected_attributes = attribute_names.reduce({}) do |hash, name|
-            hash.merge(name => expected.read_attribute(name))
-          end
-
-          @actual_attributes = attribute_names.reduce({}) do |hash, name|
-            hash.merge(name => actual.read_attribute(name))
-          end
-        end
       end
     end
   end

lib/super_diff/diff_formatters.rb

@@ -3,10 +3,12 @@ module DiffFormatters
     autoload :Array, "super_diff/diff_formatters/array"
     autoload :Base, "super_diff/diff_formatters/base"
     autoload :Collection, "super_diff/diff_formatters/collection"
+    autoload :CustomObject, "super_diff/diff_formatters/custom_object"
+    autoload :DefaultObject, "super_diff/diff_formatters/default_object"
     autoload :Hash, "super_diff/diff_formatters/hash"
     autoload :MultilineString, "super_diff/diff_formatters/multiline_string"
-    autoload :Object, "super_diff/diff_formatters/object"
 
+    # TODO: Why doesn't this include CustomObject and DefaultObject?
     DEFAULTS = [Array, Hash, MultilineString].freeze
   end
 end

lib/super_diff/diff_formatters/custom_object.rb

@@ -0,0 +1,30 @@
+module SuperDiff
+  module DiffFormatters
+    class CustomObject < DefaultObject
+      def self.applies_to?(operations)
+        operations.is_a?(OperationSequences::CustomObject)
+      end
+
+      def call
+        Collection.call(
+          open_token: "#<#{value_class} {",
+          close_token: "}>",
+          collection_prefix: collection_prefix,
+          build_item_prefix: -> (operation) {
+            key =
+              if operation.respond_to?(:left_key)
+                operation.left_key
+              else
+                operation.key
+              end
+
+            "#{key}: "
+          },
+          operations: operations,
+          indent_level: indent_level,
+          add_comma: add_comma?,
+        )
+      end
+    end
+  end
+end

lib/super_diff/diff_formatters/object.rb renamed to lib/super_diff/diff_formatters/default_object.rb

@@ -1,8 +1,8 @@
 module SuperDiff
   module DiffFormatters
-    class Object < Base
+    class DefaultObject < Base
       def self.applies_to?(operations)
-        operations.is_a?(OperationSequences::Object)
+        operations.is_a?(OperationSequences::DefaultObject)
       end
 
       def initialize(operations, value_class: nil, **rest)
@@ -24,7 +24,7 @@ def call
                 operation.key
               end
 
-            "#{key}: "
+            "@#{key}="
           },
           operations: operations,
           indent_level: indent_level,

lib/super_diff/differs.rb

@@ -1,12 +1,20 @@
 module SuperDiff
   module Differs
-    autoload :Base, "super_diff/differs/base"
     autoload :Array, "super_diff/differs/array"
+    autoload :Base, "super_diff/differs/base"
+    autoload :CustomObject, "super_diff/differs/custom_object"
+    autoload :DefaultObject, "super_diff/differs/default_object"
     autoload :Empty, "super_diff/differs/empty"
     autoload :Hash, "super_diff/differs/hash"
     autoload :MultilineString, "super_diff/differs/multiline_string"
-    autoload :Object, "super_diff/differs/object"
 
-    DEFAULTS = [Array, Hash, MultilineString, Object, Empty].freeze
+    DEFAULTS = [
+      Array,
+      Hash,
+      MultilineString,
+      CustomObject,
+      DefaultObject,
+      Empty,
+    ].freeze
   end
 end

lib/super_diff/differs/object.rb renamed to lib/super_diff/differs/custom_object.rb

@@ -1,8 +1,9 @@
 module SuperDiff
   module Differs
-    class Object < Base
+    class CustomObject < Base
       def self.applies_to?(expected, actual)
-        expected.is_a?(::Object) && actual.is_a?(::Object)
+        expected.respond_to?(:attributes_for_super_diff) &&
+          actual.respond_to?(:attributes_for_super_diff)
       end
 
       def call
@@ -12,14 +13,7 @@ def call
       private
 
       def operations
-        OperationalSequencer.call(
-          expected: expected,
-          actual: actual,
-          extra_classes: extra_operational_sequencer_classes,
-          extra_diff_formatter_classes: extra_diff_formatter_classes,
-        )
-      rescue SuperDiff::NoOperationalSequencerAvailableError
-        OperationalSequencers::Object.call(
+        OperationalSequencers::CustomObject.call(
           expected: expected,
           actual: actual,
           extra_operational_sequencer_classes: extra_operational_sequencer_classes,

lib/super_diff/differs/default_object.rb

@@ -0,0 +1,25 @@
+module SuperDiff
+  module Differs
+    class DefaultObject < Base
+      def self.applies_to?(_expected, _actual)
+        true
+      end
+
+      def call
+        operations.to_diff(indent_level: indent_level)
+      end
+
+      private
+
+      def operations
+        OperationalSequencer.call(
+          expected: expected,
+          actual: actual,
+          all_or_nothing: true,
+          extra_classes: extra_operational_sequencer_classes,
+          extra_diff_formatter_classes: extra_diff_formatter_classes,
+        )
+      end
+    end
+  end
+end

lib/super_diff/equality_matchers/object.rb

@@ -33,7 +33,7 @@ def fail
       protected
 
       def diff
-        Differs::Object.call(
+        Differ.call(
           expected,
           actual,
           indent_level: 0,

lib/super_diff/operation_sequences.rb

@@ -2,7 +2,8 @@ module SuperDiff
   module OperationSequences
     autoload :Array, "super_diff/operation_sequences/array"
     autoload :Base, "super_diff/operation_sequences/base"
+    autoload :CustomObject, "super_diff/operation_sequences/custom_object"
+    autoload :DefaultObject, "super_diff/operation_sequences/default_object"
     autoload :Hash, "super_diff/operation_sequences/hash"
-    autoload :Object, "super_diff/operation_sequences/object"
   end
 end

lib/super_diff/operation_sequences/custom_object.rb

@@ -0,0 +1,15 @@
+module SuperDiff
+  module OperationSequences
+    class CustomObject < DefaultObject
+      def to_diff(indent_level:, add_comma: false, collection_prefix: nil)
+        DiffFormatters::CustomObject.call(
+          self,
+          indent_level: indent_level,
+          collection_prefix: collection_prefix,
+          add_comma: add_comma,
+          value_class: value_class,
+        )
+      end
+    end
+  end
+end