Merge pull request #4686 from rmosolgo/fix-rails-without-logger

Fix default_logger when Rails doesn't have a logger

lib/graphql/schema.rb

@@ -842,8 +842,8 @@ def default_logger(new_default_logger = NOT_CONFIGURED)
             @default_logger
           elsif superclass.respond_to?(:default_logger)
             superclass.default_logger
-          elsif defined?(Rails)
-            Rails.logger
+          elsif defined?(Rails) && Rails.respond_to?(:logger) && (rails_logger = Rails.logger)
+            rails_logger
           else
             def_logger = Logger.new($stdout)
             def_logger.info! # It doesn't output debug info by default

spec/graphql/logger_spec.rb

@@ -5,12 +5,40 @@
   describe "Schema.default_logger" do
     if defined?(Rails)
       it "When Rails is present, returns the Rails logger" do
+        prev_logger = Rails.logger # might be `nil`
+        Rails.logger = Object.new
         assert_equal Rails.logger, GraphQL::Schema.default_logger
+      ensure
+        Rails.logger = prev_logger
       end
+
+      it "When Rails is present but the logger is nil, it returns a new logger" do
+        prev_logger = Rails.logger
+        Rails.logger = nil
+        refute_equal Rails.logger, GraphQL::Schema.default_logger
+        assert_instance_of Logger, GraphQL::Schema.default_logger
+      ensure
+        Rails.logger = prev_logger
+      end
+
     else
       it "Without Rails, returns a new logger" do
         assert_instance_of Logger, GraphQL::Schema.default_logger
       end
+
+      it "Works when Rails doesn't have a logger" do
+        rails_mod = Module.new
+        Object.const_set(:Rails, rails_mod)
+        assert_equal rails_mod, Rails
+        assert_instance_of Logger, GraphQL::Schema.default_logger
+
+        rails_mod.define_singleton_method(:logger) { false }
+        assert Rails.respond_to?(:logger)
+        assert_equal false, Rails.logger
+        assert_instance_of Logger, GraphQL::Schema.default_logger
+      ensure
+        Object.send :remove_const, :Rails
+      end
     end
 
     it "can be overridden" do