feat: add has_last_result? to workflow info

Author: chris-olszewski

temporalio/lib/temporalio/internal/worker/workflow_instance.rb

@@ -133,6 +133,7 @@ def initialize(details)
               last_result: if @init_job.last_completion_result
                              @payload_converter.from_payloads(@init_job.last_completion_result).first
                            end,
+              has_last_result?: !@init_job.last_completion_result.nil?,
               namespace: details.namespace,
               parent: if @init_job.parent_workflow_info
                         Workflow::Info::ParentInfo.new(

temporalio/lib/temporalio/workflow/info.rb

@@ -11,6 +11,7 @@ module Workflow
       :headers,
       :last_failure,
       :last_result,
+      :has_last_result?,
       :namespace,
       :parent,
       :priority,
@@ -44,6 +45,9 @@ module Workflow
     #   @return [Exception, nil] Failure if this workflow run is a continuation of a failure.
     # @!attribute last_result
     #   @return [Object, nil] Successful result if this workflow is a continuation of a success.
+    # @!attribute has_last_result?
+    #   @return [Boolean] Successful result if this workflow is a continuation of a success.
+
     # @!attribute namespace
     #   @return [String] Namespace for the workflow.
     # @!attribute parent

temporalio/sig/temporalio/workflow/info.rbs

@@ -9,6 +9,7 @@ module Temporalio
       attr_reader headers: Hash[String, untyped]
       attr_reader last_failure: Exception?
       attr_reader last_result: Object?
+      attr_reader has_last_result?: bool
       attr_reader namespace: String
       attr_reader parent: ParentInfo?
       attr_reader priority: Temporalio::Priority
@@ -31,6 +32,7 @@ module Temporalio
         headers: Hash[String, untyped],
         last_failure: Exception?,
         last_result: Object?,
+        has_last_result?: bool,
         namespace: String,
         parent: ParentInfo?,
         priority: Temporalio::Priority?,

temporalio/test/client_test.rb

@@ -267,4 +267,90 @@ def test_binary_metadata
   ensure
     env.client.connection.rpc_metadata = orig_metadata
   end
+
+  class ScheduleResult
+    def initialize(client, handle)
+      @handle = handle
+      @client = client
+    end
+
+    def result
+      desc = @handle.describe
+      # oldest first
+      workflow_id = desc.info.recent_actions.last&.action&.workflow_id
+      return nil if workflow_id.nil?
+
+      workflow_handle = @client.workflow_handle(workflow_id)
+      workflow_handle.result
+    end
+  end
+
+  class LastResultWorkflow < Temporalio::Workflow::Definition
+    def execute
+      last_result = Temporalio::Workflow.info.last_result
+      return "The last result was #{last_result}" unless last_result.nil?
+
+      'First result'
+    end
+  end
+
+  def test_last_completion_result
+    id = "wf-#{SecureRandom.uuid}"
+    task_queue = "tq-#{SecureRandom.uuid}"
+    handle = env.client.create_schedule(
+      'last-result-workflow',
+      Temporalio::Client::Schedule.new(
+        action: Temporalio::Client::Schedule::Action::StartWorkflow.new(
+          LastResultWorkflow,
+          id:, task_queue:
+        ),
+        spec: Temporalio::Client::Schedule::Spec.new
+      )
+    )
+
+    schedule = ScheduleResult.new(env.client, handle)
+
+    Temporalio::Worker.new(client: env.client, task_queue:, workflows: [LastResultWorkflow]).run do
+      handle.trigger
+      assert_equal 'First result', schedule.result
+
+      handle.trigger
+      assert_equal 'The last result was First result', schedule.result
+    end
+
+    handle.delete
+  end
+
+  class HasLastResultWorkflow < Temporalio::Workflow::Definition
+    def execute # rubocop:disable Naming/PredicateMethod
+      Temporalio::Workflow.info.has_last_result?
+    end
+  end
+
+  def test_has_last_completion_result
+    id = "wf-#{SecureRandom.uuid}"
+    task_queue = "tq-#{SecureRandom.uuid}"
+    handle = env.client.create_schedule(
+      'has-last-result-workflow',
+      Temporalio::Client::Schedule.new(
+        action: Temporalio::Client::Schedule::Action::StartWorkflow.new(
+          HasLastResultWorkflow,
+          id:, task_queue:
+        ),
+        spec: Temporalio::Client::Schedule::Spec.new
+      )
+    )
+
+    schedule = ScheduleResult.new(env.client, handle)
+
+    Temporalio::Worker.new(client: env.client, task_queue:, workflows: [HasLastResultWorkflow]).run do
+      handle.trigger
+      assert_equal false, schedule.result
+
+      handle.trigger
+      assert_equal true, schedule.result
+    end
+
+    handle.delete
+  end
 end

temporalio/test/worker_workflow_test.rb

@@ -206,6 +206,7 @@ def test_info
       assert_nil info.fetch('execution_timeout')
       assert_nil info.fetch('last_failure')
       assert_nil info.fetch('last_result')
+      assert_equal false, info.fetch('has_last_result?')
       assert_equal env.client.namespace, info['namespace']
       assert_nil info.fetch('parent')
       assert_nil info.fetch('retry_policy')
@@ -2653,6 +2654,35 @@ def test_non_durable_timer
                                      .map { |a| a.start_to_fire_timeout.to_f })
     end
   end
+
+  class LastFailureWorkflow < Temporalio::Workflow::Definition
+    workflow_query_attr_reader :failure
+
+    def execute
+      info = Temporalio::Workflow.info
+
+      @failure = info.last_failure
+
+      return 'Done' if info.attempt != 1
+
+      raise Temporalio::Error::ApplicationError.new('Intentional failure', category: Temporalio::Error::ApplicationError::Category::BENIGN)
+    end
+  end
+
+  def test_last_failure
+    execute_workflow(LastFailureWorkflow, retry_policy:
+      Temporalio::RetryPolicy.new(
+        initial_interval: 0,
+        max_attempts: 2
+      )) do |handle|
+      result = handle.result
+
+      assert_equal 'Done', result
+
+      previous_failure = handle.query(:failure)
+      assert_equal 'Intentional failure', previous_failure
+    end
+  end
 end
 
 # TODO(cretz): To test