Revert "Merge pull request #19404 from dmathieu/remove_rack_env"

Preserving RACK_ENV behavior.

This reverts commit 7bdc7635b885e473f6a577264fd8efad1c02174f, reversing
changes made to 45786be516e13d55a1fca9a4abaddd5781209103.

2 files changed, 35 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
index d0deb7751c..24f5849e45 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"] }
+    RAILS_ENV   = -> { (Rails.env if defined?(Rails.env)) || ENV["RAILS_ENV"] || ENV["RACK_ENV"] }
     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/merge_and_resolve_default_url_config_test.rb b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
index 9756a2b891..9ee92a3cd2 100644
--- a/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
+++ b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
@@ -5,11 +5,13 @@ module ActiveRecord
     class MergeAndResolveDefaultUrlConfigTest < ActiveRecord::TestCase
       def setup
         @previous_database_url = ENV.delete("DATABASE_URL")
+        @previous_rack_env = ENV.delete("RACK_ENV")
         @previous_rails_env = ENV.delete("RAILS_ENV")
       end
 
       teardown do
         ENV["DATABASE_URL"] = @previous_database_url
+        ENV["RACK_ENV"] = @previous_rack_env
         ENV["RAILS_ENV"] = @previous_rails_env
       end
 
@@ -39,6 +41,16 @@ module ActiveRecord
         assert_equal expected, actual
       end
 
+      def test_resolver_with_database_uri_and_current_env_symbol_key_and_rack_env
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+        ENV['RACK_ENV']     = "foo"
+
+        config   = { "not_production" => { "adapter" => "not_postgres", "database" => "not_foo" } }
+        actual   = resolve_spec(:foo, config)
+        expected = { "adapter" => "postgresql", "database" => "foo", "host" => "localhost" }
+        assert_equal expected, actual
+      end
+
       def test_resolver_with_database_uri_and_known_key
         ENV['DATABASE_URL'] = "postgres://localhost/foo"
         config   = { "production" => { "adapter" => "not_postgres", "database" => "not_foo", "host" => "localhost" } }
@@ -161,6 +173,28 @@ module ActiveRecord
         assert_equal nil,      actual[:test]
       end
 
+      def test_blank_with_database_url_with_rack_env
+        ENV['RACK_ENV'] = "not_production"
+        ENV['DATABASE_URL'] = "postgres://localhost/foo"
+
+        config   = {}
+        actual   = resolve_config(config)
+        expected = { "adapter"  => "postgresql",
+                     "database" => "foo",
+                     "host"     => "localhost" }
+
+        assert_equal expected, actual["not_production"]
+        assert_equal nil,      actual["production"]
+        assert_equal nil,      actual["default_env"]
+        assert_equal nil,      actual["development"]
+        assert_equal nil,      actual["test"]
+        assert_equal nil,      actual[:default_env]
+        assert_equal nil,      actual[:not_production]
+        assert_equal nil,      actual[:production]
+        assert_equal nil,      actual[:development]
+        assert_equal nil,      actual[:test]
+      end
+
       def test_database_url_with_ipv6_host_and_port
         ENV['DATABASE_URL'] = "postgres://[::1]:5454/foo"