stock_picking_many2many

A wave groups work across several transfers so a picker walks the warehouse once. Adding a transfer to a wave is therefore not a link: move lines have to be split, reassigned and re-sequenced, and only the server can do that correctly.

This widget makes the interface match. Rather than the standard add action writing a relation, it opens a selection of transfers and, once chosen, creates the wizard Odoo already uses for this and calls its attach method.

It also filters the selection. Transfers already on the wave are excluded from the dialog, so the list never offers something that is already there.

Wave picking only pays off if building a wave is quick, and the difference between a good and a bad implementation is usually how many wrong choices the interface allows. Excluding what is already attached removes one whole category of mistake.

The design point is that the server owns the operation. Anything that reshapes stock moves should be a server call, not a relation write, and this widget is a clean example of an interface deferring to that rather than trying to model it in the browser.

The usual usage

<field name="picking_ids"
       widget="stock_picking_many2many">
  <list> ... </list>
</field>

No options. Adding opens the selection rather than a plain link action.

What happens on selection

# a wizard record is created, then
stock.add.to.wave.attach_pickings(...)
# and the returned action is opened

The server does the splitting and reassignment.

The plain relation

<field name="picking_ids" widget="many2many"/>

Writes the relation directly, which is not enough for a wave.

The selection is built in two steps. First the widget wraps the standard select-and-create helper so that its own domain is appended before the dialog opens. That domain excludes the transfers already linked, filtered down to those with a real database identifier.

Second, the selection handler does not write anything to the relation. It creates a wizard record carrying the wave and the chosen transfers, calls the wizard's attach method with a context flag saying the call came from the wave form, and opens whatever action the server returns.

That context flag is worth noting: the same wizard is reachable from elsewhere, and the flag is how the server distinguishes the two entry points.

The last piece is a forced many-to-many semantic. The widget always reports the relation as linked rather than owned, so the framework offers linking and unlinking rather than creating and deleting, which is correct because a transfer exists independently of any wave.

Odoo 20 is expected at Odoo Experience in Brussels, 24 to 26 September 2026. The development branch is unstable and this may still change; we re-verify this page after the release.

Byte-identical. The file on the development branch matches Odoo 19 exactly, including the exclusion domain and the wizard call.