Fixes bugs for using indexes in CREATE TABLE by adding checks for table existence

Also:
  - updates tests by stubbing table_exists? method
  - adds entry for creating indexes in CREATE TABLE to changelog

2 files changed, 2 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 59210c345f..23404a5c48 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -795,7 +795,7 @@ module ActiveRecord
           if index_name.length > max_index_length
             raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{max_index_length} characters"
           end
-          if index_name_exists?(table_name, index_name, false)
+          if table_exists?(table_name) && index_name_exists?(table_name, index_name, false)
             raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists"
           end
           index_columns = quoted_columns_for_index(column_names, options).join(", ")
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 96c7d5d7eb..a1748c9261 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -12,7 +12,7 @@ module ActiveRecord
           statements = []
           statements.concat(o.columns.map { |c| accept c })
           statements.concat(o.indexes.map { |(column_name, options)| index_in_create(o.name, column_name, options) })
-          create_sql << "(#{statements.join(', ')}) "
+          create_sql << "(#{statements.join(', ')}) " if statements.present?
           create_sql << "#{o.options}"
           create_sql << " AS #{@conn.to_sql(o.as)}" if o.as
           create_sql