TracDev/ApiChanges/0.13

0.13 corresponds to the development version of Trac (a.k.a. trunk​)
These notes reflect the current status.

Summary

1. Prerequisites
   1. Modified Dependencies
      1. Babel (optional)
2. Detailed List of Developer Visible Changes
3. Other Modifications made to the 0.12 API
   1. Database API Changes
      1. Environment.get_db_cnx is obsolete
4. 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).

Detailed List of Developer Visible Changes

Component: database backend (1 match)

Ticket	API Changes
#8575	trac.db: Added a method update_sequence() to database connections to allow updating table sequences during schema updates. [10114]

Other Modifications made to the 0.12 API

Database API 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Environment.get_db_cnx is obsolete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.