Only lookup `config.log_level` for stdlib `::Logger`. Closes #11665.

This prevents Rails from assigning meaningless log levels to third
party loggers like log4r. If `Rails.logger` is not `kind_of?(::Logger)`
we simply assign the `config.log_level` as is.

This bug was introduced by #11665.

1 files changed, 5 insertions, 1 deletions

diff --git a/railties/lib/rails/application/bootstrap.rb b/railties/lib/rails/application/bootstrap.rb
index a26d41c0cf..33bcab1e57 100644
--- a/railties/lib/rails/application/bootstrap.rb
+++ b/railties/lib/rails/application/bootstrap.rb
@@ -53,7 +53,11 @@ INFO
           logger
         end
 
-        Rails.logger.level = ActiveSupport::Logger.const_get(config.log_level.to_s.upcase)
+        if ::Logger === Rails.logger
+          Rails.logger.level = ActiveSupport::Logger.const_get(config.log_level.to_s.upcase)
+        else
+          Rails.logger.level = config.log_level
+        end
       end
 
       # Initialize cache early in the stack so railties can make use of it.