1 files changed, 83 insertions, 9 deletions
diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
index 74d0ed348e..f4cc251fb9 100644
--- a/activerecord/test/cases/connection_adapters/connection_handler_test.rb
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -1,10 +1,15 @@
 # frozen_string_literal: true
 
 require "cases/helper"
+require "models/person"
 
 module ActiveRecord
   module ConnectionAdapters
     class ConnectionHandlerTest < ActiveRecord::TestCase
+      self.use_transactional_tests = false
+
+      fixtures :people
+
       def setup
         @handler = ConnectionHandler.new
         @spec_name = "primary"
@@ -98,11 +103,11 @@ module ActiveRecord
       end
 
       def test_active_connections?
-        assert !@handler.active_connections?
+        assert_not_predicate @handler, :active_connections?
         assert @handler.retrieve_connection(@spec_name)
-        assert @handler.active_connections?
+        assert_predicate @handler, :active_connections?
         @handler.clear_active_connections!
-        assert !@handler.active_connections?
+        assert_not_predicate @handler, :active_connections?
       end
 
       def test_retrieve_connection_pool
@@ -139,6 +144,75 @@ module ActiveRecord
           rd.close
         end
 
+        def test_forked_child_doesnt_mangle_parent_connection
+          object_id = ActiveRecord::Base.connection.object_id
+          assert_predicate ActiveRecord::Base.connection, :active?
+
+          rd, wr = IO.pipe
+          rd.binmode
+          wr.binmode
+
+          pid = fork {
+            rd.close
+            if ActiveRecord::Base.connection.active?
+              wr.write Marshal.dump ActiveRecord::Base.connection.object_id
+            end
+            wr.close
+
+            exit # allow finalizers to run
+          }
+
+          wr.close
+
+          Process.waitpid pid
+          assert_not_equal object_id, Marshal.load(rd.read)
+          rd.close
+
+          assert_equal 3, ActiveRecord::Base.connection.select_value("SELECT COUNT(*) FROM people")
+        end
+
+        unless in_memory_db?
+          def test_forked_child_recovers_from_disconnected_parent
+            object_id = ActiveRecord::Base.connection.object_id
+            assert_predicate ActiveRecord::Base.connection, :active?
+
+            rd, wr = IO.pipe
+            rd.binmode
+            wr.binmode
+
+            outer_pid = fork {
+              ActiveRecord::Base.connection.disconnect!
+
+              pid = fork {
+                rd.close
+                if ActiveRecord::Base.connection.active?
+                  pair = [ActiveRecord::Base.connection.object_id,
+                          ActiveRecord::Base.connection.select_value("SELECT COUNT(*) FROM people")]
+                  wr.write Marshal.dump pair
+                end
+                wr.close
+
+                exit # allow finalizers to run
+              }
+
+              Process.waitpid pid
+            }
+
+            wr.close
+
+            Process.waitpid outer_pid
+            child_id, child_count = Marshal.load(rd.read)
+
+            assert_not_equal object_id, child_id
+            rd.close
+
+            assert_equal 3, child_count
+
+            # Outer connection is unaffected
+            assert_equal 6, ActiveRecord::Base.connection.select_value("SELECT 2 * COUNT(*) FROM people")
+          end
+        end
+
         def test_retrieve_connection_pool_copies_schema_cache_from_ancestor_pool
           @pool.schema_cache = @pool.connection.schema_cache
           @pool.schema_cache.add("posts")
@@ -200,15 +274,15 @@ module ActiveRecord
         def test_a_class_using_custom_pool_and_switching_back_to_primary
           klass2 = Class.new(Base) { def self.name; "klass2"; end }
 
-          assert_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+          assert_same klass2.connection, ActiveRecord::Base.connection
 
           pool = klass2.establish_connection(ActiveRecord::Base.connection_pool.spec.config)
-          assert_equal klass2.connection.object_id, pool.connection.object_id
-          refute_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+          assert_same klass2.connection, pool.connection
+          refute_same klass2.connection, ActiveRecord::Base.connection
 
           klass2.remove_connection
 
-          assert_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+          assert_same klass2.connection, ActiveRecord::Base.connection
         end
 
         def test_connection_specification_name_should_fallback_to_parent
@@ -223,8 +297,8 @@ module ActiveRecord
         def test_remove_connection_should_not_remove_parent
           klass2 = Class.new(Base) { def self.name; "klass2"; end }
           klass2.remove_connection
-          refute_nil ActiveRecord::Base.connection.object_id
-          assert_equal klass2.connection.object_id, ActiveRecord::Base.connection.object_id
+          refute_nil ActiveRecord::Base.connection
+          assert_same klass2.connection, ActiveRecord::Base.connection
         end
       end
     end