replace raise with throw to handle context failure (#126)

Author: hedgesky

lib/interactor.rb

@@ -112,8 +112,16 @@ def initialize(context = {})
   #
   # Returns nothing.
   def run
-    run!
-  rescue Failure
+    catch(:early_return) do
+      with_hooks do
+        call
+        context.called!(self)
+      end
+    end
+    context.rollback! if context.failure?
+  rescue
+    context.rollback!
+    raise
   end
 
   # Internal: Invoke an Interactor instance along with all defined hooks. The
@@ -139,13 +147,8 @@ def run
   # Returns nothing.
   # Raises Interactor::Failure if the context is failed.
   def run!
-    with_hooks do
-      call
-      context.called!(self)
-    end
-  rescue
-    context.rollback!
-    raise
+    run
+    raise(Failure, context) if context.failure?
   end
 
   # Public: Invoke an Interactor instance without any hooks, tracking, or

lib/interactor/context.rb

@@ -123,7 +123,7 @@ def failure?
     def fail!(context = {})
       context.each { |key, value| modifiable[key.to_sym] = value }
       @failure = true
-      raise Failure, self
+      throw :early_return
     end
 
     # Internal: Track that an Interactor has been called. The "called!" method

lib/interactor/organizer.rb

@@ -8,7 +8,7 @@ module Interactor
   #   class MyOrganizer
   #     include Interactor::Organizer
   #
-  #     organizer InteractorOne, InteractorTwo
+  #     organize InteractorOne, InteractorTwo
   #   end
   module Organizer
     # Internal: Install Interactor::Organizer's behavior in the given class.
@@ -76,7 +76,8 @@ module InstanceMethods
       # Returns nothing.
       def call
         self.class.organized.each do |interactor|
-          interactor.call!(context)
+          throw(:early_return) if context.failure?
+          interactor.call(context)
         end
       end
     end

spec/interactor/context_spec.rb

@@ -109,18 +109,10 @@ module Interactor
         }.from("bar").to("baz")
       end
 
-      it "raises failure" do
+      it "throws :early_return" do
         expect {
           context.fail!
-        }.to raise_error(Failure)
-      end
-
-      it "makes the context available from the failure" do
-        begin
-          context.fail!
-        rescue Failure => error
-          expect(error.context).to eq(context)
-        end
+        }.to throw_symbol(:early_return)
       end
     end
 

spec/interactor/organizer_spec.rb

@@ -33,25 +33,34 @@ module Interactor
 
     describe "#call" do
       let(:instance) { organizer.new }
-      let(:context) { double(:context) }
+      let(:context) { double(:context, failure?: false) }
       let(:interactor2) { double(:interactor2) }
       let(:interactor3) { double(:interactor3) }
       let(:interactor4) { double(:interactor4) }
+      let(:organized_interactors) { [interactor2, interactor3, interactor4] }
 
       before do
         allow(instance).to receive(:context) { context }
-        allow(organizer).to receive(:organized) {
-          [interactor2, interactor3, interactor4]
-        }
+        allow(organizer).to receive(:organized) { organized_interactors }
+        organized_interactors.each do |organized_interactor|
+          allow(organized_interactor).to receive(:call)
+        end
       end
 
       it "calls each interactor in order with the context" do
-        expect(interactor2).to receive(:call!).once.with(context).ordered
-        expect(interactor3).to receive(:call!).once.with(context).ordered
-        expect(interactor4).to receive(:call!).once.with(context).ordered
+        expect(interactor2).to receive(:call).once.with(context).ordered
+        expect(interactor3).to receive(:call).once.with(context).ordered
+        expect(interactor4).to receive(:call).once.with(context).ordered
 
         instance.call
       end
+
+      it "throws :early_return on failure of one of organizers" do
+        allow(context).to receive(:failure?).and_return(false, true)
+        expect {
+          instance.call
+        }.to throw_symbol(:early_return)
+      end
     end
   end
 end

spec/support/lint.rb

@@ -1,6 +1,14 @@
 shared_examples :lint do
   let(:interactor) { Class.new.send(:include, described_class) }
 
+  let(:context_double) do
+    double(:double, failure?: false, called!: nil, rollback!: nil)
+  end
+
+  let(:failed_context_double) do
+    double(:failed_context_double, failure?: true, called!: nil, rollback!: nil)
+  end
+
   describe ".call" do
     let(:context) { double(:context) }
     let(:instance) { double(:instance, context: context) }
@@ -66,52 +74,84 @@
     let(:instance) { interactor.new }
 
     it "runs the interactor" do
-      expect(instance).to receive(:run!).once.with(no_args)
+      expect(instance).to receive(:call).once.with(no_args)
 
       instance.run
     end
 
-    it "rescues failure" do
-      expect(instance).to receive(:run!).and_raise(Interactor::Failure)
-
+    it "catches :early_return" do
+      allow(instance).to receive(:call).and_throw(:early_return)
       expect {
         instance.run
-      }.not_to raise_error
+      }.not_to throw_symbol
     end
 
-    it "raises other errors" do
-      expect(instance).to receive(:run!).and_raise("foo")
+    context "when error is raised inside #call" do
+      it "propagates it and rollbacks context" do
+        allow(instance).to receive(:context) { context_double }
+        allow(instance).to receive(:call).and_raise("foo")
 
-      expect {
+        expect(instance.context).to receive(:rollback!)
+        expect {
+          instance.run
+        }.to raise_error("foo")
+      end
+    end
+
+    context "on call failure" do
+      before do
+        allow(instance).to receive(:context) { failed_context_double }
+      end
+
+      it "doesn't raise Failure" do
+        expect {
+          instance.run
+        }.not_to raise_error
+      end
+
+      it "rollbacks context on error" do
+        expect(instance.context).to receive(:rollback!)
         instance.run
-      }.to raise_error("foo")
+      end
     end
   end
 
   describe "#run!" do
     let(:instance) { interactor.new }
 
     it "calls the interactor" do
-      expect(instance).to receive(:call).once.with(no_args)
+      expect(instance).to receive(:run).once.with(no_args)
 
       instance.run!
     end
 
-    it "raises failure" do
-      expect(instance).to receive(:run!).and_raise(Interactor::Failure)
-
-      expect {
-        instance.run!
-      }.to raise_error(Interactor::Failure)
-    end
-
-    it "raises other errors" do
-      expect(instance).to receive(:run!).and_raise("foo")
+    it "propagates errors" do
+      expect(instance).to receive(:run).and_raise("foo")
 
       expect {
         instance.run
       }.to raise_error("foo")
     end
+
+    context "on failure" do
+      before do
+        allow(instance).to receive(:context) { failed_context_double }
+      end
+
+      it "raises Interactor::Failure" do
+        expect {
+          instance.run!
+        }.to raise_error(Interactor::Failure)
+      end
+
+      it "makes context available from the error" do
+        begin
+          instance.run!
+        rescue Interactor::Failure => error
+          expect(error.context).to be(instance.context)
+        end
+      end
+    end
   end
 
   describe "#call" do