paso a pos.sessions más natural, los apuntes están ahí.

pos_account_payment_order_sepa/data/server_action.xml

@@ -2,37 +2,38 @@
 <odoo>
     <record id="action_pos_collect_sepa" model="ir.actions.server">
         <field name="name">Collect by SEPA direct debit</field>
-        <field name="model_id" ref="point_of_sale.model_pos_order" />
-        <field name="binding_model_id" ref="point_of_sale.model_pos_order" />
+        <field name="model_id" ref="point_of_sale.model_pos_session" />
+        <field name="binding_model_id" ref="point_of_sale.model_pos_session" />
         <field name="binding_view_types">list,form</field>
         <field name="state">code</field>
         <field name="code"><![CDATA[
-# Collect the still-open "Customer Account" receivables generated by the
-# selected POS orders through a SEPA direct debit payment order (debit
-# order). For each order we take the receivable journal item of its session
-# move, keep the unreconciled ones whose partner has a valid SEPA mandate,
-# and create the payment lines inside a single draft inbound payment order.
-# The SEPA XML (pain.008) is generated afterwards from that order by the user.
+# Collect the still-open "Customer Account" receivables of the selected POS
+# sessions through a SEPA direct debit payment order (debit order).
 #
-# Orders are skipped (and reported) when: no accounting move yet, no open
+# Unfactured POS orders do not get their own accounting move: the receivable
+# generated by a "Customer Account" payment method (split_transactions) lands
+# in the SINGLE journal entry of the session (session.move_id). So we read the
+# open receivable lines from that move, keep the ones whose partner has a valid
+# SEPA mandate, and create the payment lines inside a draft inbound payment
+# order. The SEPA file (pain.008) is generated afterwards from that order.
+#
+# Lines are skipped (and reported) when: the session has no move yet, no open
 # receivable line, no partner, the line is already in a payment order, or the
-# partner has no valid SEPA mandate. Refunds/credit lines are ignored.
+# partner has no valid SEPA mandate.
 
 Mode = env["account.payment.mode"]
 Order = env["account.payment.order"]
 Mandate = env["account.banking.mandate"]
+PaymentLine = env["account.payment.line"]
 
 # --- Resolve the inbound SEPA payment mode (partner mode, with fallback) ---
-def sepa_mode_for(partner):
-    mode = partner.customer_payment_mode_id
-    if (
+def is_sepa_inbound(mode):
+    return bool(
         mode
         and mode.payment_order_ok
         and mode.payment_method_id.code == "sepa_direct_debit"
         and mode.payment_method_id.payment_type == "inbound"
-    ):
-        return mode
-    return False
+    )
 
 fallback_mode = Mode.search(
     [
@@ -43,12 +44,12 @@ fallback_mode = Mode.search(
     limit=1,
 )
 
-# --- Classify the selected orders ---
+# --- Collect open receivable lines from the selected sessions' moves ---
 lines_by_mode = {}
 skipped = {"no_move": 0, "no_line": 0, "no_partner": 0, "already": 0, "no_mandate": 0, "no_mode": 0}
 
-for order in records:
-    move = order.account_move
+for session in records:
+    move = session.move_id
     if not move:
         skipped["no_move"] += 1
         continue
@@ -65,7 +66,7 @@ for order in records:
         if not partner:
             skipped["no_partner"] += 1
             continue
-        if env["account.payment.line"].search_count(
+        if PaymentLine.search_count(
             [("move_line_id", "=", line.id), ("order_id.state", "!=", "cancel")]
         ):
             skipped["already"] += 1
@@ -75,7 +76,8 @@ for order in records:
         ):
             skipped["no_mandate"] += 1
             continue
-        mode = sepa_mode_for(partner) or fallback_mode
+        partner_mode = partner.customer_payment_mode_id
+        mode = partner_mode if is_sepa_inbound(partner_mode) else fallback_mode
         if not mode:
             skipped["no_mode"] += 1
             continue
@@ -86,7 +88,6 @@ for order in records:
 created_lines = 0
 order_names = []
 for mode_id, move_lines in lines_by_mode.items():
-    mode = Mode.browse(mode_id)
     payment_order = Order.search(
         [("payment_mode_id", "=", mode_id), ("state", "=", "draft")], limit=1
     )
@@ -101,9 +102,9 @@ message = (
     "Payment lines created: %(created)s\n"
     "Payment order(s): %(orders)s\n\n"
     "Skipped:\n"
-    "  no accounting move: %(no_move)s\n"
-    "  no open receivable line: %(no_line)s\n"
-    "  no partner: %(no_partner)s\n"
+    "  session without accounting move: %(no_move)s\n"
+    "  session without open receivable line: %(no_line)s\n"
+    "  line without partner: %(no_partner)s\n"
     "  already in a payment order: %(already)s\n"
     "  no valid SEPA mandate: %(no_mandate)s\n"
     "  no SEPA payment mode: %(no_mode)s"