New Tryton release 2.6

We are happy to announce the 2.6 release of Tryton.

This release brings major changes in the API with the introduction of the Active Record pattern. But also the graphical user interface was not left without improvements. And as usual there are many bug-fixes, module improvements and new modules (as announced in the previous release news).

Of course, migration from previous series is fully supported.

Major changes in graphical user interface

Management of model access and create/delete field access.

The client is now aware of the model access which allows the disable buttons when the user doesn't have access to it.

It is also possible to manage the create/delete event on fields in addition to read/write.
Dynamic size limit on the One2Many, Many2Many and Char.

It is now possible to limit the size of those fields and the client will enforce it.
Remove "Please wait" box. The popup was annoying because it make the client lost the focus.
Paste in editable list view. It is possible to paste from a spreadsheet to update a set of rows.

Major changes on the server side

Allow to use Reference field in One2Many & Many2Many.

In addition to the Many2One, the reverse field could be a Reference field. In the future, the link between Move and Shipments will be done like that instead of having 4 exclusive Many2One fields.
All kind of buttons have been merge into one simple concept.
Active Record: This is the result of refactoring work started 2 years ago.

Here are some benefits:
- Reduce the amount of code (about 2.2k lines removed) for example on_change_with and getter of Function field can be merged.
- Unify access to the value of record if it is stored or not in the database. It allows to remove of values dictionary on on_change method.
- Remove loop over ids in getter of Function field:
  
  before:
```
def getter(self, ids, name):
    res = {}
    for record in self.browse(ids):
        res[record.id] = …
    return res
```
  after:
```
def getter(self, name):
    return self.…
```
- Rationale the register process of Model (use copy of fields etc.)
- Remove session in wizard. Now the wizard instance is the session.
Allow to store the views in a XML file instead of the database. This supports the modification of a view without updating the database. A good speedup for designing views.
A new kind of validation has been added the pre_validation.

The new pre_validation allows to validate a record without saving it. This is used by the client to validate lines of a One2Many. With pre_validation it is possible to provide feedback to the user as soon as possible and before the record is saved.

Modules

account

The Trial Balance report displays now the start and end balance in addition to the debit and credit columns.
Double-clicking on Balance Sheet opens accounts.
The Account Chart doesn't show cumulate Debit/Credit by default but only for the current period.
The Aged Balance is computed over all fiscalyears.
The Account Moves have been refactored to include an origin field which allows to easily link it to the master document. They have two number fields for draft and posted.

account_stock_continental

Updating cost price create automaticaly a stock accounting move.

purchase

The purchase manages negative quantities on lines, they will generate Return Shipments and Credit Note.

stock

A graph has been added showing the evolution in past and future of the stock level for a product per warehouse.

New modules

stock_lot defines lot of products.
stock_split adds a wizard to split move.
account_fr adds French account chart.
production defines the basics for production management.
stock_supply_production adds automatic supply mechanisms via production requests.

Other changes graphical user interface

Constant interpolation has been added to line graph.
The group could have a readonly state.
It is possible to define a time format different of the classic '%H:%M:%S'.

Other changes on server side

The ModelSQL.default_sequence has been removed. The sequence fields will no more increase indefinitely.
The time format is validated, so it is possible to enforce the second to 0 for example.
__tryton__.py is replaced by tryton.cfg, a static file.
It is possible to use tuple as Reference value. It is useful to construct dynamic domain on such field in PYSON.