Bring back "database already exists" messages when running rake tasks

When running tasks such "rake db:setup", instead of showing messages
like "db_development already exists", it was showing a big stack trace
and a message "Couldn't create database for ..." with the configuration
options, a very confusing message with a big trace.

This brings back the functionality present in 3-2, showing the same
message.

1 files changed, 10 insertions, 0 deletions

diff --git a/activerecord/test/cases/tasks/postgresql_rake_test.rb b/activerecord/test/cases/tasks/postgresql_rake_test.rb
index 62acd53003..3006a87589 100644
--- a/activerecord/test/cases/tasks/postgresql_rake_test.rb
+++ b/activerecord/test/cases/tasks/postgresql_rake_test.rb
@@ -61,6 +61,16 @@ module ActiveRecord
 
       ActiveRecord::Tasks::DatabaseTasks.create @configuration
     end
+
+    def test_create_when_database_exists_outputs_info_to_stderr
+      $stderr.expects(:puts).with("my-app-db already exists").once
+
+      ActiveRecord::Base.connection.stubs(:create_database).raises(
+        ActiveRecord::StatementInvalid.new('database "my-app-db" already exists')
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
   end
 
   class PostgreSQLDBDropTest < ActiveRecord::TestCase