From d749227e87bfc5df96a5b2fbace7601a83351633 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Guitaut?= <loic@discourse.org>
Date: Tue, 20 Aug 2024 12:05:41 +0200
Subject: [PATCH] DEV: Allow using an AR relation as a model in services

This patch allows using an AR relation as a model in services without
fetching associated records. It will just check if the relation is empty
or not. In the former case, the execution will stop at that point, as
expected.
---
 {plugins/chat/app => app}/jobs/service_job.rb |  0
 app/services/service/base.rb                  |  6 ++-
 lib/service_runner.rb                         |  4 +-
 .../spec => spec}/lib/service_runner_spec.rb  | 44 ++++++++++++++++++-
 4 files changed, 50 insertions(+), 4 deletions(-)
 rename {plugins/chat/app => app}/jobs/service_job.rb (100%)
 rename {plugins/chat/spec => spec}/lib/service_runner_spec.rb (90%)

diff --git a/plugins/chat/app/jobs/service_job.rb b/app/jobs/service_job.rb
similarity index 100%
rename from plugins/chat/app/jobs/service_job.rb
rename to app/jobs/service_job.rb
diff --git a/app/services/service/base.rb b/app/services/service/base.rb
index 531169f44cd..08f60c6a487 100644
--- a/app/services/service/base.rb
+++ b/app/services/service/base.rb
@@ -139,13 +139,15 @@ module Service
 
       def call(instance, context)
         context[name] = super
-        raise ArgumentError, "Model not found" if !optional && context[name].blank?
+        if !optional && (!context[name] || context[name].try(:empty?))
+          raise ArgumentError, "Model not found"
+        end
         if context[name].try(:invalid?)
           context[result_key].fail(invalid: true)
           context.fail!
         end
       rescue ArgumentError => exception
-        context[result_key].fail(exception: exception)
+        context[result_key].fail(exception: exception, not_found: true)
         context.fail!
       end
     end
diff --git a/lib/service_runner.rb b/lib/service_runner.rb
index 7dbec6e7a67..05c9f507709 100644
--- a/lib/service_runner.rb
+++ b/lib/service_runner.rb
@@ -80,7 +80,9 @@ class ServiceRunner
       default_name: "default",
     },
     on_model_not_found: {
-      condition: ->(name = "model") { failure_for?("result.model.#{name}") && result[name].blank? },
+      condition: ->(name = "model") do
+        failure_for?("result.model.#{name}") && result["result.model.#{name}"].not_found
+      end,
       key: %w[result model],
       default_name: "model",
     },
diff --git a/plugins/chat/spec/lib/service_runner_spec.rb b/spec/lib/service_runner_spec.rb
similarity index 90%
rename from plugins/chat/spec/lib/service_runner_spec.rb
rename to spec/lib/service_runner_spec.rb
index 9afa8d39722..bfd6eb653c4 100644
--- a/plugins/chat/spec/lib/service_runner_spec.rb
+++ b/spec/lib/service_runner_spec.rb
@@ -136,6 +136,18 @@ RSpec.describe ServiceRunner do
     end
   end
 
+  class RelationModelService
+    include Service::Base
+
+    model :fake_model
+
+    private
+
+    def fetch_fake_model
+      User.where(admin: false)
+    end
+  end
+
   describe ".call(service, &block)" do
     subject(:runner) { described_class.call(service, object, &actions_block) }
 
@@ -145,7 +157,9 @@ RSpec.describe ServiceRunner do
     let(:actions) { "proc {}" }
     let(:object) do
       Class
-        .new(Chat::ApiController) do
+        .new(ApplicationController) do
+          include WithServiceHelper
+
           def request
             OpenStruct.new
           end
@@ -352,6 +366,34 @@ RSpec.describe ServiceRunner do
           end
         end
       end
+
+      context "when fetching an ActiveRecord relation" do
+        let(:service) { RelationModelService }
+
+        context "when the service does not fail" do
+          before { Fabricate(:user) }
+
+          it "does not run the provided block" do
+            expect(runner).not_to eq :no_model
+          end
+
+          it "does not fetch records from the relation" do
+            runner
+            expect(result[:fake_model]).not_to be_loaded
+          end
+        end
+
+        context "when the service fails" do
+          it "runs the provided block" do
+            expect(runner).to eq :no_model
+          end
+
+          it "does not fetch records from the relation" do
+            runner
+            expect(result[:fake_model]).not_to be_loaded
+          end
+        end
+      end
     end
 
     context "when using the on_model_errors action" do