Only subscribe to Rails.error if connects_to is configured

The previous behavior could lead to strange errors if solid_errors is not configured in the given environment. The error reporter would try to write to solid_errors table, but the table is not available in the default database. With that if statement in place, the subscriber will only be added, if solid_errors is enabled for the environment.

Author: sascha-karnatz

lib/solid_errors/engine.rb

@@ -18,7 +18,7 @@ class Engine < ::Rails::Engine
     end
 
     initializer "solid_errors.active_record.error_subscriber" do
-      Rails.error.subscribe(SolidErrors::Subscriber.new)
+      Rails.error.subscribe(SolidErrors::Subscriber.new) if config.solid_errors.connects_to.present?
     end
   end
 end

test/engine_test.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class EngineTest < Minitest::Test
+  def setup
+    @config = Rails.application.config
+    @original_connects_to = @config.solid_errors.connects_to
+    @subscriber = nil
+  end
+
+  def teardown
+    Rails.error.unsubscribe(@subscriber) if @subscriber
+    @config.solid_errors.connects_to = @original_connects_to
+  end
+
+  def test_subscriber_is_enabled_when_connects_to_is_present
+    @config.solid_errors.connects_to = {database: {writing: :primary}}
+
+    run_subscriber_initializer
+
+    assert solid_errors_subscriber, "Subscriber should be registered when connects_to is configured"
+  end
+
+  def test_subscriber_is_disabled_when_connects_to_is_nil
+    @config.solid_errors.connects_to = nil
+
+    run_subscriber_initializer
+
+    refute solid_errors_subscriber, "Subscriber should not be registered when connects_to is nil"
+  end
+
+  private
+
+  def run_subscriber_initializer
+    initializer = SolidErrors::Engine.initializers.find { |i| i.name == "solid_errors.active_record.error_subscriber" }
+    SolidErrors::Engine.instance_exec(Rails.application, &initializer.block)
+  end
+
+  def solid_errors_subscriber
+    subscribers = Rails.error.instance_variable_get(:@subscribers)
+    @subscriber = subscribers.find { |s| s.is_a?(SolidErrors::Subscriber) }
+  end
+end