[FIX] mrp: state on workorder with 0 batch size

Usecase:
- Go on a BoM with a routing. Go on the first operation and set
the next operation(batch field) as 'Once a minimum number of products is
processed'.
- Set the batch size (minimum operation) to 0.
- Create a MO and plan it.
- The second work order has state 'pending' instead of 'ready'

It happens because the system automatically set the first wo as
'ready' and the following as 'pending' and don't check the batch
and batch_size.

closes odoo/odoo#32628

Signed-off-by: Simon Lejeune (sle) <sle@openerp.com>

addons/mrp/models/mrp_production.py

@@ -583,7 +583,7 @@ class MrpProduction(models.Model):
             })
             if workorders:
                 workorders[-1].next_work_order_id = workorder.id
-                workorders[-1]._init_nextworkorder_states()
+                workorders[-1]._start_nextworkorder()
             workorders += workorder
 
             # assign moves; last operation receive all unassigned moves (which case ?)

addons/mrp/models/mrp_workorder.py

@@ -337,9 +337,6 @@ class MrpWorkorder(models.Model):
                 move_line.lot_produced_id = self.final_lot_id.id
                 move_line.done_wo = True
 
-        # One a piece is produced, you can launch the next work order
-        self._start_nextworkorder()
-
         self.move_line_ids.filtered(
             lambda move_line: not move_line.done_move and not move_line.lot_produced_id and move_line.qty_done > 0
         ).write({
@@ -390,6 +387,9 @@ class MrpWorkorder(models.Model):
             self.final_lot_id.use_next_on_work_order_id = self.next_work_order_id
             self.final_lot_id = False
 
+        # One a piece is produced, you can launch the next work order
+        self._start_nextworkorder()
+
         # Set a qty producing
         rounding = self.production_id.product_uom_id.rounding
         if float_compare(self.qty_produced, self.production_id.product_qty, precision_rounding=rounding) >= 0:
@@ -411,12 +411,13 @@ class MrpWorkorder(models.Model):
 
     @api.multi
     def _start_nextworkorder(self):
-        for record in self:
-            if record.next_work_order_id.state == 'pending':
-                record.next_work_order_id.state = 'ready'
-
-    def _init_nextworkorder_states(self):
-        return 'pending'
+        rounding = self.product_id.uom_id.rounding
+        if self.next_work_order_id.state == 'pending' and (
+                (self.operation_id.batch == 'no' and
+                 float_compare(self.qty_production, self.qty_produced, precision_rounding=rounding) <= 0) or
+                (self.operation_id.batch == 'yes' and
+                 float_compare(self.operation_id.batch_size, self.qty_produced, precision_rounding=rounding) <= 0)):
+            self.next_work_order_id.state = 'ready'
 
     @api.multi
     def button_start(self):