symfony/symfony — pull request #6276 by stloyd (2012-12-12 09:16:21+00:00)
Title: [HttpFoundation] Default request `_format` should be aware of HTTP Accept header

Bug fix: no
Feature addition: yes
Backwards compatibility break: yes (?)
Symfony2 tests pass: yes
Fixes the following tickets: #4567

Possible __BC break__ would be in really edge case that is user sets `$default` format and expects it will be returned but now if `Accept` header is set, it has priority over default value.