1 files changed, 15 insertions, 1 deletions
diff --git a/railties/lib/rails/application/bootstrap.rb b/railties/lib/rails/application/bootstrap.rb
index a26d41c0cf..71d3febde4 100644
--- a/railties/lib/rails/application/bootstrap.rb
+++ b/railties/lib/rails/application/bootstrap.rb
@@ -1,5 +1,6 @@
 require "active_support/notifications"
 require "active_support/dependencies"
+require "active_support/deprecation"
 require "active_support/descendants_tracker"
 
 module Rails
@@ -47,12 +48,25 @@ INFO
           logger = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDERR))
           logger.level = ActiveSupport::Logger::WARN
           logger.warn(
-            "Rails Error: Unable to access log file. Please ensure that #{path} exists and is chmod 0666. " +
+            "Rails Error: Unable to access log file. Please ensure that #{path} exists and is writable " +
+            "(ie, make it writable for user and group: chmod 0664 #{path}). " +
             "The log level has been raised to WARN and the output directed to STDERR until the problem is fixed."
           )
           logger
         end
 
+        if Rails.env.production? && !config.has_explicit_log_level?
+          ActiveSupport::Deprecation.warn \
+           "You did not specify a `log_level` in `production.rb`. Currently, " \
+           "the default value for `log_level` is `:info` for the production " \
+           "environment and `:debug` in all other environments. In Rails 5 " \
+           "the default value will be unified to `:debug` across all " \
+           "environments. To preserve the current setting, add the following " \
+           "line to your `production.rb`:\n" \
+           "\n" \
+           "   config.log_level = :info\n\n"
+        end
+
         Rails.logger.level = ActiveSupport::Logger.const_get(config.log_level.to_s.upcase)
       end