TracDev/ApiChanges/0.13

Summary

1. Prerequisites
   1. Modified Dependencies
      1. Babel (optional)
2. Modifications made to the 0.12 API
   1. Other Changes
      1. Environment.get_db_cnx is obsolete
3. New in the 0.13 API
   1. Other news
      1. Environment.db_query() and Environment.db_transaction() ^(0.13)​

Prerequisites

Python 2.4 support has been dropped. Python versions 2.5, 2.6 and 2.7 are supported.

Modified Dependencies

Babel (optional)

The internationalization support (i18) for Trac is depending on ​Babel.

Q: Should we now make Babel a mandatory dependency, as we have a good stable release?

This would allow us to use the Babel API in more places (e.g. #4636, #2182).

Modifications made to the 0.12 API

Other Changes

Environment.get_db_cnx is obsolete

Following the deprecation deprecation made in 0.12, using Environment.get_db_cnx for obtaining a database connection is now no longer necessary.

One should use the context managers for retrieving a database Connection in read or write mode. TODO

• a read-only Connection can be used to form queries:

  with env.db_query as db:
      ...
  

  a db instance obtained the above way should only be used for executing SELECT queries
• a write Connection can be used to modify the database content in a transaction:

  with env.db_transaction as db:
      ...
  

  a db instance obtained the above way can be used to execute INSERT/UPDATE/DELETE queries; they will be committed when the last such automatic transaction in the control flow completes successfully (see details further down)

New in the 0.13 API

Other news

Environment.db_query() and Environment.db_transaction() ^(0.13)​

The @with_transaction(env) / @env.with_transaction() decorators introduced in 0.12 remain available, but they're now deprecated as well, as the with syntax is to be preferred. TODO

See #8751 for details and related notes about get_db_cnx deprecation above.