Implement proper delete_if for embeds_many.

[ close #2324 ]
[ close #2339 ]

CHANGELOG.md

@@ -26,6 +26,8 @@ For instructions on upgrading to newer versions, visit
         Band.where(name: "Depeche Mode").pluck(:_id)
         Band.where(name: "Tool").pluck(:likes)
 
+* \#2324 Embeds many relations now properly handle `delete_if`.
+
 * \#2317 Added `Document.first_or_create` and `Criteria#first_or_create`.
   This will return the first matching document or create one with additional
   attributes if one does not exist. (incorvia)

lib/mongoid/relations/embedded/many.rb

@@ -165,6 +165,28 @@ def delete_all(conditions = {})
           remove_all(conditions, :delete)
         end
 
+        # Delete all the documents for which the provided block returns true.
+        #
+        # @example Delete the matching documents.
+        #   person.addresses.delete_if do |doc|
+        #     doc.state = "GA"
+        #   end
+        #
+        # @return [ Many, Enumerator ] The relation or an enumerator if no
+        #   block was provided.
+        #
+        # @since 3.1.0
+        def delete_if
+          if block_given?
+            target.each do |doc|
+              delete(doc) if yield(doc)
+            end
+            self
+          else
+            super
+          end
+        end
+
         # Destroy all the documents in the association whilst running callbacks.
         #
         # @example Destroy all documents from the relation.

spec/mongoid/relations/embedded/many_spec.rb

@@ -1560,6 +1560,112 @@ class TrackingIdValidationHistory
     end
   end
 
+  describe "#delete_if" do
+
+    let(:person) do
+      Person.create
+    end
+
+    context "when the documents are new" do
+
+      let!(:address_one) do
+        person.addresses.build(street: "Bond")
+      end
+
+      let!(:address_two) do
+        person.addresses.build(street: "Upper")
+      end
+
+      context "when a block is provided" do
+
+        let!(:deleted) do
+          person.addresses.delete_if do |doc|
+            doc.street == "Bond"
+          end
+        end
+
+        it "removes the matching documents" do
+          person.addresses.size.should eq(1)
+        end
+
+        it "removes from the unscoped" do
+          person.addresses.send(:_unscoped).size.should eq(1)
+        end
+
+        it "returns the relation" do
+          deleted.should eq(person.addresses)
+        end
+      end
+
+      context "when no block is provided" do
+
+        let!(:deleted) do
+          person.addresses.delete_if
+        end
+
+        it "returns an enumerator" do
+          deleted.should be_a(Enumerator)
+        end
+      end
+    end
+
+    context "when the documents persisted" do
+
+      let!(:address_one) do
+        person.addresses.create(street: "Bond")
+      end
+
+      let!(:address_two) do
+        person.addresses.create(street: "Upper")
+      end
+
+      context "when a block is provided" do
+
+        let!(:deleted) do
+          person.addresses.delete_if do |doc|
+            doc.street == "Bond"
+          end
+        end
+
+        it "deletes the matching documents" do
+          person.addresses.count.should eq(1)
+        end
+
+        it "deletes the matching documents from the db" do
+          person.reload.addresses.count.should eq(1)
+        end
+
+        it "returns the relation" do
+          deleted.should eq(person.addresses)
+        end
+      end
+    end
+
+    context "when the documents are empty" do
+
+      context "when a block is provided" do
+
+        let!(:deleted) do
+          person.addresses.delete_if do |doc|
+            doc.street == "Bond"
+          end
+        end
+
+        it "deletes the matching documents" do
+          person.addresses.count.should eq(0)
+        end
+
+        it "deletes all the documents from the db" do
+          person.reload.addresses.count.should eq(0)
+        end
+
+        it "returns the relation" do
+          deleted.should eq(person.addresses)
+        end
+      end
+    end
+  end
+
   [ :delete_all, :destroy_all ].each do |method|
 
     describe "##{method}" do