diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
index 2ede92feff048500527c7b5610dfd83521fb324a..b8fbb489b6084862f8d2b732ea5a4a2602ea190f 100644
--- a/activerecord/lib/active_record/connection_handling.rb
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module ConnectionHandling
-    RAILS_ENV   = -> { (Rails.env if defined?(Rails.env)) || ENV["RAILS_ENV"] || ENV["RACK_ENV"] }
+    RAILS_ENV   = -> { (Rails.env if defined?(Rails.env)) || ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence }
     DEFAULT_ENV = -> { RAILS_ENV.call || "default_env" }
 
     # Establishes the connection to the database. Accepts a hash as input where
diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
index 681399c8bb03dba48351bdaeed1220bb21ca2335..2a71f08d9052ad2f175c3fdd9ec3e1a652b679fc 100644
--- a/activerecord/test/cases/connection_adapters/connection_handler_test.rb
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -9,6 +9,17 @@ def setup
         @pool = @handler.establish_connection(ActiveRecord::Base.configurations["arunit"])
       end
 
+      def test_default_env_fall_back_to_default_env_when_rails_env_or_rack_env_is_empty_string
+        original_rails_env = ENV["RAILS_ENV"]
+        original_rack_env  = ENV["RACK_ENV"]
+        ENV["RAILS_ENV"]   = ENV["RACK_ENV"] = ""
+
+        assert_equal "default_env", ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
+      ensure
+        ENV["RAILS_ENV"] = original_rails_env
+        ENV["RACK_ENV"]  = original_rack_env
+      end
+
       def test_establish_connection_uses_spec_name
         config = { "readonly" => { "adapter" => "sqlite3" } }
         resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(config)
diff --git a/railties/lib/rails/command.rb b/railties/lib/rails/command.rb
index 0d4e6dc5a138515cfe2af9affa01839140914013..ee020b58f97ebf2afc56ed857b4559f12e6c0c55 100644
--- a/railties/lib/rails/command.rb
+++ b/railties/lib/rails/command.rb
@@ -23,7 +23,7 @@ def hidden_commands # :nodoc:
       end
 
       def environment # :nodoc:
-        ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development"
+        ENV["RAILS_ENV"].presence || ENV["RACK_ENV"].presence || "development"
       end
 
       # Receives a namespace, arguments and the behavior to invoke the command.