rails--rails/actionpack/CHANGELOG.md

• Fix Mime::Type.parse when bad accepts header is looked up. Previously it was setting request.formats with an array containing a nil value, which raised an error when setting the controller formats.

  Fixes #10965

  Becker

• Merge :action from routing scope and assign endpoint if both :controller and :action are present. The endpoint assignment only occurs if there is no :to present in the options hash so should only affect routes using the shorthand syntax (i.e. endpoint is inferred from the path).

  Fixes #9856

  Yves Senn, Andrew White

• ActionView extracted from ActionPack

  Piotr Sarnacki, Łukasz Strzałkowski

• Fix removing trailing slash for mounted apps #3215

  Piotr Sarnacki

Please check 4-0-stable for previous changes.