From a6a3f903c8cdbd7aac15ce07da2977667b0cb4f7 Mon Sep 17 00:00:00 2001
From: Florian da Costa <florian.dacosta@akretion.com>
Date: Tue, 1 Nov 2016 18:26:40 +0100
Subject: [PATCH] fixes #587

---
 database_cleanup/models/__init__.py        |  1 +
 database_cleanup/models/ir_model_fields.py | 17 +++++++++++++++++
 database_cleanup/models/purge_models.py    |  1 +
 3 files changed, 19 insertions(+)
 create mode 100644 database_cleanup/models/ir_model_fields.py

diff --git a/database_cleanup/models/__init__.py b/database_cleanup/models/__init__.py
index 004a4e3bb..1857ee3b0 100644
--- a/database_cleanup/models/__init__.py
+++ b/database_cleanup/models/__init__.py
@@ -5,3 +5,4 @@ from . import purge_columns
 from . import purge_tables
 from . import purge_data
 from . import purge_menus
+from . import ir_model_fields
diff --git a/database_cleanup/models/ir_model_fields.py b/database_cleanup/models/ir_model_fields.py
new file mode 100644
index 000000000..ffb2988ac
--- /dev/null
+++ b/database_cleanup/models/ir_model_fields.py
@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+# © 2014-2016 Therp BV <http://therp.nl>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+from openerp import api, models
+
+
+class IrModelFields(models.Model):
+    _inherit = 'ir.model.fields'
+
+    # In case of purging it means the model does not exist anymore in
+    # installed module. In this specific case, we need to avoid to check
+    # if fields can be removed as it would fail.
+    @api.multi
+    def _prepare_update(self):
+        if self.env.context.get('purge'):
+            self -= self.filtered(lambda x: x.model not in self.env.registry)
+        return super(IrModelFields, self)._prepare_update()
diff --git a/database_cleanup/models/purge_models.py b/database_cleanup/models/purge_models.py
index 996cea61d..181ccd101 100644
--- a/database_cleanup/models/purge_models.py
+++ b/database_cleanup/models/purge_models.py
@@ -54,6 +54,7 @@ class CleanupPurgeLineModel(models.TransientModel):
         context_flags = {
             MODULE_UNINSTALL_FLAG: True,
             'no_drop_table': True,
+            'purge': True,
         }
 
         for line in self: