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.

3 files changed, 27 insertions, 7 deletions

diff --git a/activerecord/test/cases/tasks/database_tasks_test.rb b/activerecord/test/cases/tasks/database_tasks_test.rb
index 4f3489b7a5..659d5eae72 100644
--- a/activerecord/test/cases/tasks/database_tasks_test.rb
+++ b/activerecord/test/cases/tasks/database_tasks_test.rb
@@ -11,10 +11,10 @@ module ActiveRecord
   end
 
   ADAPTERS_TASKS = {
-     :mysql      => :mysql_tasks,
-     :mysql2     => :mysql_tasks,
-     :postgresql => :postgresql_tasks,
-     :sqlite3    => :sqlite_tasks
+    mysql:      :mysql_tasks,
+    mysql2:     :mysql_tasks,
+    postgresql: :postgresql_tasks,
+    sqlite3:    :sqlite_tasks
   }
 
   class DatabaseTasksRegisterTask < ActiveRecord::TestCase
@@ -32,7 +32,7 @@ module ActiveRecord
       ActiveRecord::Tasks::DatabaseTasks.structure_dump({'adapter' => :foo}, "awesome-file.sql")
     end
   end
- 
+
   class DatabaseTasksCreateTest < ActiveRecord::TestCase
     include DatabaseTasksSetupper
 
@@ -258,7 +258,7 @@ module ActiveRecord
 
   class DatabaseTasksCharsetTest < ActiveRecord::TestCase
     include DatabaseTasksSetupper
- 
+
     ADAPTERS_TASKS.each do |k, v|
       define_method("test_#{k}_charset") do
         eval("@#{v}").expects(:charset)
@@ -269,7 +269,7 @@ module ActiveRecord
 
   class DatabaseTasksCollationTest < ActiveRecord::TestCase
     include DatabaseTasksSetupper
- 
+
     ADAPTERS_TASKS.each do |k, v|
       define_method("test_#{k}_collation") do
         eval("@#{v}").expects(:collation)
diff --git a/activerecord/test/cases/tasks/mysql_rake_test.rb b/activerecord/test/cases/tasks/mysql_rake_test.rb
index 69a049fcfa..38b9dd02f0 100644
--- a/activerecord/test/cases/tasks/mysql_rake_test.rb
+++ b/activerecord/test/cases/tasks/mysql_rake_test.rb
@@ -53,6 +53,16 @@ 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("Can't create database 'dev'; database exists:")
+      )
+
+      ActiveRecord::Tasks::DatabaseTasks.create @configuration
+    end
   end
 
   class MysqlDBCreateAsRootTest < ActiveRecord::TestCase
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