Merge pull request mongodb#4035 from sivagollapalli/issue_3966

Added spec for issue #3966

lib/mongoid/relations/embedded/many.rb

@@ -170,7 +170,8 @@ def delete_all(conditions = {})
         # @since 3.1.0
         def delete_if
           if block_given?
-            target.each do |doc|
+            dup_target = target.dup
+            dup_target.each do |doc|
               delete(doc) if yield(doc)
             end
             self

spec/app/models/company.rb

@@ -0,0 +1,5 @@
+class Company
+  include Mongoid::Document
+
+  embeds_many :staffs
+end

spec/app/models/staff.rb

@@ -0,0 +1,7 @@
+class Staff
+  include Mongoid::Document
+
+  embedded_in :company
+
+  field :age, type: Integer
+end

spec/mongoid/relations/embedded/many_spec.rb

@@ -3933,4 +3933,15 @@ class TrackingIdValidationHistory
       expect(loaded.extension).to eq("Testing")
     end
   end
+
+  context "deleting embedded documents" do
+    it "able to delete embedded documents upon condition" do
+      company = Company.new
+      4.times { |i| company.staffs << Staff.new(age: 50 + i)}
+      2.times { |i| company.staffs << Staff.new(age: 40)}
+      company.save
+      company.staffs.delete_if {|x| x.age >= 50}
+      expect(company.staffs.count).to eq(2)
+    end
+  end
 end