Backport PostgreSQL auto-reconnect test coverage

6d5f4de4c420ebb906109668f5702a537ac77692
Simulated & actual (manual/skipped) PostgreSQL auto-reconnection tests.

4b1bca04025a66c54e6e9d5eb6e4d4056bfa92f0
Stop being silly with formatting of method aliasing.

c381d5cbf959208adeb38e7859ee815dfbd2cf54
Fix just-plain-wrongness of psql auto-reconnect test.

1e17a9d367c54c680368be72f44247ae28b98904
Fix only-once stub logic.

f16c2043826ec1991cf94fe17cb671507b7a7f51
Changelog for PostgreSQL auto-reconnect test coverage backport.

activerecord/CHANGELOG.md

@@ -1,4 +1,9 @@
 ## Rails 3.2.9 (unreleased)
+*   Backport test coverage to ensure that PostgreSQL auto-reconnect functionality
+    remains healthy.
+
+    *Steve Jorgensen
+
 *   Use config['encoding'] instead of config['charset'] when executing
     databases.rake in the mysql/mysql2. A correct option for a database.yml
     is 'encoding'.

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -354,6 +354,7 @@ module ActiveRecord
       def reconnect!
         clear_cache!
         @connection.reset
+        @open_transactions = 0
         configure_connection
       end
 

activerecord/test/cases/adapters/postgresql/connection_test.rb

@@ -10,5 +10,79 @@ module ActiveRecord
     def test_encoding
       assert_not_nil @connection.encoding
     end
+
+    def test_reconnection_after_simulated_disconnection_with_verify
+      assert @connection.active?
+      original_connection_pid = @connection.query('select pg_backend_pid()')
+
+      # Fail with bad connection on next query attempt.
+      raw_connection = @connection.raw_connection
+      raw_connection_class = class << raw_connection ; self ; end
+      raw_connection_class.class_eval <<-CODE, __FILE__, __LINE__ + 1
+        def query_fake(*args)
+          if !( @called ||= false )
+            self.stubs(:status).returns(PGconn::CONNECTION_BAD)
+            @called = true
+            raise PGError
+          else
+            self.unstub(:status)
+            query_unfake(*args)
+          end
+        end
+
+        alias query_unfake query
+        alias query        query_fake
+      CODE
+
+      begin
+        @connection.verify!
+        new_connection_pid = @connection.query('select pg_backend_pid()')
+      ensure
+        raw_connection_class.class_eval <<-CODE
+          alias query query_unfake
+          undef query_fake
+        CODE
+      end
+
+      assert_not_equal original_connection_pid, new_connection_pid, "Should have a new underlying connection pid"
+    end
+
+    # Must have with_manual_interventions set to true for this
+    # test to run.
+    # When prompted, restart the PostgreSQL server with the
+    # "-m fast" option or kill the individual connection assuming
+    # you know the incantation to do that.
+    # To restart PostgreSQL 9.1 on OS X, installed via MacPorts, ...
+    # sudo su postgres -c "pg_ctl restart -D /opt/local/var/db/postgresql91/defaultdb/ -m fast"
+    def test_reconnection_after_actual_disconnection_with_verify
+      skip "with_manual_interventions is false in configuration" unless ARTest.config['with_manual_interventions']
+
+      original_connection_pid = @connection.query('select pg_backend_pid()')
+
+      # Sanity check.
+      assert @connection.active?
+
+      puts 'Kill the connection now (e.g. by restarting the PostgreSQL ' +
+           'server with the "-m fast" option) and then press enter.'
+      $stdin.gets
+
+      @connection.verify!
+
+      assert @connection.active?
+
+      # If we get no exception here, then either we re-connected successfully, or
+      # we never actually got disconnected.
+      new_connection_pid = @connection.query('select pg_backend_pid()')
+
+      assert_not_equal original_connection_pid, new_connection_pid,
+        "umm -- looks like you didn't break the connection, because we're still " +
+        "successfully querying with the same connection pid."
+
+      # Repair all fixture connections so other tests won't break.
+      @fixture_connections.each do |c|
+        c.verify!
+      end
+    end
+
   end
 end

activerecord/test/config.example.yml

@@ -1,5 +1,7 @@
 default_connection: <%= defined?(JRUBY_VERSION) ? 'jdbcsqlite3' : 'sqlite3' %>
 
+with_manual_interventions: false
+
 connections:
   jdbcderby:
     arunit:  activerecord_unittest