Ensure add_column gives valid error for sqlite. [Gunnar Wolf, Pratik] [#197 state:resolved]

SQLite#add_column executes "VACUUM", which fails if inside a live transaction. This patch
ensures a valid exception is raised if add_column is executed within a live transaction for
sqlite adapter.

1 files changed, 4 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index 8abbc6d0a4..51cfd10e5c 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -214,6 +214,10 @@ module ActiveRecord
       end
 
       def add_column(table_name, column_name, type, options = {}) #:nodoc:
+        if @connection.respond_to?(:transaction_active?) && @connection.transaction_active?
+          raise StatementInvalid, 'Cannot add columns to a SQLite database while inside a transaction'
+        end
+        
         super(table_name, column_name, type, options)
         # See last paragraph on http://www.sqlite.org/lang_altertable.html
         execute "VACUUM"