Safe spawn and where.not

lib/active_hash/conditions.rb

@@ -7,6 +7,11 @@ def initialize(conditions = [])
     @conditions = conditions
   end
 
+  def initialize_copy(orig)
+    super
+    @conditions = @conditions.dup
+  end
+
   def matches?(record)
     conditions.all? do |condition|
       condition.matches?(record)

lib/active_hash/relation.rb

@@ -19,7 +19,7 @@ def initialize(klass, all_records, conditions = nil, order_values = nil)
     end
 
     def where(conditions_hash = :chain)
-      return WhereChain.new(self) if conditions_hash == :chain
+      return WhereChain.new(spawn) if conditions_hash == :chain
 
       spawn.where!(conditions_hash)
     end
@@ -80,7 +80,7 @@ def invert_where!
     end
 
     def spawn
-      self.class.new(klass, all_records, conditions, order_values)
+      self.class.new(klass, all_records, conditions.dup, order_values)
     end
 
     def order!(*options)

spec/active_hash/base_spec.rb

@@ -497,6 +497,12 @@ class Region < ActiveHash::Base
     it "filters records for multiple conditions" do
       expect(Country.where.not(:id => 1, :name => 'Mexico')).to match_array([Country.find(2)])
     end
+
+    it "does not mutate the parent relation" do
+      english = Country.where(language: 'English')
+      english.where.not(name: 'US')
+      expect(english.map(&:name)).to match_array(%w[US Canada])
+    end
   end
 
   describe ".find_by" do
@@ -574,6 +580,14 @@ class Region < ActiveHash::Base
     it "doesn't finds nil records when searching for ''" do
       expect(Country.find_by(:language => '')).to be_nil
     end
+
+    it "does not mutate the relation when called multiple times" do
+      countries = Country.all
+      expect(countries.find_by(id: 1).name).to eq("US")
+      expect(countries.find_by(id: 2).name).to eq("Canada")
+      expect(countries.find_by(id: 1).name).to eq("US")
+      expect(countries.length).to eq(4)
+    end
   end
 
   describe ".find_by!" do