Cannot enter a supplier invoice without product on an invoice line

[Yannick Vaucher @ Camptocamp]

Here is the trace

Server Traceback (most recent call last):
  File ".../webclient/addons/web/session.py", line 89, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File ".../server/openerp/netsvc.py", line 296, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File ".../server/openerp/service/web_services.py", line 626, in dispatch
    res = fn(db, uid, *params)
  File ".../server/openerp/osv/osv.py", line 190, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File ".../server/openerp/osv/osv.py", line 132, in wrapper
    return f(self, dbname, *args, **kwargs)
  File ".../server/openerp/osv/osv.py", line 199, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File ".../server/openerp/osv/osv.py", line 187, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File ".../l10n_ch/l10n_ch_base_bank/invoice.py", line 122, in create
    return super(AccountInvoice, self).create(cursor, uid, vals, context=context)
  File ".../bank-statement-reconcile/account_invoice_reference/account_move.py", line 84, in create
    context=context)
  File ".../addons/mail/mail_thread.py", line 250, in create
    thread_id = super(mail_thread, self).create(cr, uid, values, context=context_operation)
  File ".../openerp-connector/connector/producer.py", line 42, in create
    record_id = create_original(self, cr, uid, vals, context=context)
  File ".../server/openerp/osv/orm.py", line 4555, in create
    self.pool.get(object)._store_set_values(cr, user, ids, fields2, context)
  File ".../server/openerp/osv/orm.py", line 4682, in _store_set_values
    result = self._columns[val[0]].get(cr, self, ids, val, SUPERUSER_ID, context=context)
  File ".../server/openerp/osv/fields.py", line 1142, in get
    result = self._fnct(obj, cr, uid, ids, name, self._arg, context)
  File ".../margin-analysis/product_historical_margin/invoice.py", line 102, in _compute_line_values
    ['id','cost_price'], context=ctx)
  File ".../server/openerp/osv/orm.py", line 3677, in read
    result = self._read_flat(cr, user, select, fields, context, load)
  File ".../margin-analysis/product_cost_incl_bom_price_history/product.py", line 149, in _read_flat
    load=load)
  File ".../server/openerp/osv/orm.py", line 3729, in _read_flat
    cr.execute(query, [tuple(sub_ids)] + rule_params)
  File ".../server/openerp/sql_db.py", line 161, in wrapper
    return f(self, *args, **kwargs)
  File ".../server/openerp/sql_db.py", line 226, in execute
    res = self._obj.execute(query, params)
ProgrammingError: operator does not exist: integer = boolean
LINE 1: ...d FROM "product_product" WHERE product_product.id IN (false)...
                                                             ^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.