From 9c3c022ffe2cd3c846c96edd73a7a37ca6fd7879 Mon Sep 17 00:00:00 2001
From: Guewen Baconnier <guewen.baconnier@camptocamp.com>
Date: Mon, 28 Nov 2016 09:37:57 +0100
Subject: [PATCH] [FIX] base: error in QWeb when a record is empty

When using a many2one widget, in the following scenario:

<h2><span t-field="o.partner_id.parent_id.country_id"/></h2>

If 'parent_id' is an empty recordset, the following error will be
raised:
[...]
    [read] = record.read([field_name])
ValueError: need more than 0 values to unpack

This is because record.read([field_name]) returns an empty list which
cannot be unpacked.

In version 10 this problem is avoided by using recordset but to keep the diff
minmal in v9, only returns empty string as the line below does
`if not read[field_name]: return ''`

Closes #14489
---
 openerp/addons/base/ir/ir_qweb.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/openerp/addons/base/ir/ir_qweb.py b/openerp/addons/base/ir/ir_qweb.py
index 530f7be5f19..4d7e5a02061 100644
--- a/openerp/addons/base/ir/ir_qweb.py
+++ b/openerp/addons/base/ir/ir_qweb.py
@@ -798,6 +798,8 @@ class ManyToOneConverter(osv.AbstractModel):
     _inherit = 'ir.qweb.field'
 
     def record_to_html(self, cr, uid, field_name, record, options=None, context=None):
+        if not record:
+            return ''
         [read] = record.read([field_name])
         if not read[field_name]: return ''
         _, value = read[field_name]