From 126ebbc905af9f7eb5a4887cfb57ef7944bec019 Mon Sep 17 00:00:00 2001
From: Raphael Collet <rco@odoo.com>
Date: Fri, 21 Aug 2020 08:40:47 +0000
Subject: [PATCH] [IMP] core: error message for computed field left unassigned

Non-stored readonly computed fields must be assigned by compute method.
Make the error message more explicit.

closes odoo/odoo#56269

Signed-off-by: Raphael Collet (rco) <rco@openerp.com>
---
 .../test_new_api/models/test_new_api.py       | 27 +++++++++++++++++++
 .../test_new_api/security/ir.model.access.csv |  1 +
 .../test_new_api/tests/test_new_fields.py     | 19 +++++++++++++
 odoo/fields.py                                |  4 +--
 4 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/odoo/addons/test_new_api/models/test_new_api.py b/odoo/addons/test_new_api/models/test_new_api.py
index 99f0fd65b68..4ca9417ae5a 100644
--- a/odoo/addons/test_new_api/models/test_new_api.py
+++ b/odoo/addons/test_new_api/models/test_new_api.py
@@ -594,6 +594,33 @@ class ComputeOnchangeLine(models.Model):
                                 required=True, ondelete='cascade')
 
 
+class ComputeUnassigned(models.Model):
+    _name = 'test_new_api.compute.unassigned'
+    _description = "Model with computed fields left unassigned"
+
+    foo = fields.Char()
+    bar = fields.Char(compute='_compute_bar')
+    bare = fields.Char(compute='_compute_bare', readonly=False)
+    bars = fields.Char(compute='_compute_bars', store=True)
+    bares = fields.Char(compute='_compute_bares', readonly=False, store=True)
+
+    @api.depends('foo')
+    def _compute_bar(self):
+        pass
+
+    @api.depends('foo')
+    def _compute_bare(self):
+        pass
+
+    @api.depends('foo')
+    def _compute_bars(self):
+        pass
+
+    @api.depends('foo')
+    def _compute_bares(self):
+        pass
+
+
 class ModelBinary(models.Model):
     _name = 'test_new_api.model_binary'
     _description = 'Test Image field'
diff --git a/odoo/addons/test_new_api/security/ir.model.access.csv b/odoo/addons/test_new_api/security/ir.model.access.csv
index be706801d98..37b088db27e 100644
--- a/odoo/addons/test_new_api/security/ir.model.access.csv
+++ b/odoo/addons/test_new_api/security/ir.model.access.csv
@@ -26,6 +26,7 @@ access_test_new_api_cascade,access_test_new_api_cascade,model_test_new_api_casca
 access_test_new_api_compute_readwrite,access_test_new_api_compute_readwrite,model_test_new_api_compute_readwrite,,1,1,1,1
 access_test_new_api_compute_onchange,access_test_new_api_compute_onchange,model_test_new_api_compute_onchange,,1,1,1,1
 access_test_new_api_compute_onchange_line,access_test_new_api_compute_onchange_line,model_test_new_api_compute_onchange_line,,1,1,1,1
+access_test_new_api_compute_unassigned,access_test_new_api_compute_unassigned,model_test_new_api_compute_unassigned,,1,1,1,1
 access_test_new_api_binary_svg,access_test_new_api_binary_svg,model_test_new_api_binary_svg,,1,1,1,1
 access_test_new_api_monetary_base,access_test_new_api_monetary_base,model_test_new_api_monetary_base,,1,1,1,1
 access_test_new_api_monetary_related,access_test_new_api_monetary_related,model_test_new_api_monetary_related,,1,1,1,1
diff --git a/odoo/addons/test_new_api/tests/test_new_fields.py b/odoo/addons/test_new_api/tests/test_new_fields.py
index 5591ce7e4c5..f8e9e6db49c 100644
--- a/odoo/addons/test_new_api/tests/test_new_fields.py
+++ b/odoo/addons/test_new_api/tests/test_new_fields.py
@@ -615,6 +615,25 @@ class TestFields(TransactionCaseWithUserDemo):
             discussion.name = "X"
             discussion.flush()
 
+    def test_16_compute_unassigned(self):
+        model = self.env['test_new_api.compute.unassigned']
+
+        # real record
+        record = model.create({})
+        with self.assertRaises(ValueError):
+            record.bar
+        self.assertEqual(record.bare, False)
+        self.assertEqual(record.bars, False)
+        self.assertEqual(record.bares, False)
+
+        # new record
+        record = model.new()
+        with self.assertRaises(ValueError):
+            record.bar
+        self.assertEqual(record.bare, False)
+        self.assertEqual(record.bars, False)
+        self.assertEqual(record.bares, False)
+
     def test_20_float(self):
         """ test rounding of float fields """
         record = self.env['test_new_api.mixed'].create({})
diff --git a/odoo/fields.py b/odoo/fields.py
index 2838bfbef56..f4e26e7b935 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -966,8 +966,8 @@ class Field(MetaField('DummyField', (object,), {})):
                     try:
                         value = env.cache.get(record, self)
                     except CacheMiss:
-                        if self.readonly:
-                            raise
+                        if self.readonly and not self.store:
+                            raise ValueError("Compute method failed to assign %s.%s" % (record, self.name))
                         # fallback to null value if compute gives nothing
                         value = self.convert_to_cache(False, record, validate=False)
                         env.cache.set(record, self, value)