[FIX] models: copy in a given lang must keep a field's neutral value intact

Issue: when using `copy` in a given lang, the value of XML/HTML fields is
copied in its translated form, making existing translations useless.  Fix the
value of such fields by storing their original value instead.

odoo/addons/base/tests/test_translate.py

@@ -222,3 +222,52 @@ class TestTranslation(TransactionCase):
         categories = padawans_fr.search([('id', 'in', [self.customers.id, padawans.id])], order='name')
         self.assertEqual(categories.ids, [padawans.id, self.customers.id],
             "Search ordered by translated name should return Padawans (Apprentis) before Customers (Clients)")
+
+
+class TestXMLTranslation(TransactionCase):
+    def setUp(self):
+        super(TestXMLTranslation, self).setUp()
+        self.env['ir.translation'].load_module_terms(['base'], ['fr_FR'])
+
+    def test_copy(self):
+        """ Create a simple view, fill in translations, and copy it. """
+        env_en = self.env(context={})
+        env_fr = self.env(context={'lang': 'fr_FR'})
+
+        archf = '<form string="%s"><div>%s</div><div>%s</div></form>'
+        terms_en = ('Knife', 'Fork', 'Spoon')
+        terms_fr = ('Couteau', 'Fourchette', 'Cuiller')
+        view0 = self.env['ir.ui.view'].create({
+            'name': 'test',
+            'model': 'res.partner',
+            'arch': archf % terms_en,
+        })
+        for src, value in zip(terms_en, terms_fr):
+            self.env['ir.translation'].create({
+                'type': 'model',
+                'name': 'ir.ui.view,arch_db',
+                'lang': 'fr_FR',
+                'res_id': view0.id,
+                'src': src,
+                'value': value,
+            })
+
+        # check translated field
+        self.assertEqual(view0.with_env(env_en).arch_db, archf % terms_en)
+        self.assertEqual(view0.with_env(env_fr).arch_db, archf % terms_fr)
+
+        # copy without lang
+        view1 = view0.with_env(env_en).copy({})
+        self.assertEqual(view1.with_env(env_en).arch_db, archf % terms_en)
+        self.assertEqual(view1.with_env(env_fr).arch_db, archf % terms_fr)
+
+        # copy with lang='fr_FR'
+        view2 = view0.with_env(env_fr).copy({})
+        self.assertEqual(view2.with_env(env_en).arch_db, archf % terms_en)
+        self.assertEqual(view2.with_env(env_fr).arch_db, archf % terms_fr)
+
+        # copy with lang='fr_FR' and translate=html_translate
+        self.patch(type(self.env['ir.ui.view']).arch_db, 'translate', html_translate)
+        view3 = view0.with_env(env_fr).copy({})
+        self.assertEqual(view3.with_env(env_en).arch_db, archf % terms_en)
+        self.assertEqual(view3.with_env(env_fr).arch_db, archf % terms_fr)

odoo/models.py

@@ -4362,16 +4362,18 @@ class BaseModel(object):
                 # for translatable fields we copy their translations
                 trans_name, source_id, target_id = get_trans(field, old, new)
                 domain = [('name', '=', trans_name), ('res_id', '=', source_id)]
+                new_val = new_wo_lang[name]
+                if old.env.lang:
+                    # the new value *without lang* must be the old value without lang
+                    new_wo_lang[name] = old_wo_lang[name]
                 for vals in Translation.search_read(domain):
                     del vals['id']
                     del vals['source']      # remove source to avoid triggering _set_src
                     del vals['module']      # duplicated vals is not linked to any module
                     vals['res_id'] = target_id
                     if vals['lang'] == old.env.lang and field.translate is True:
-                        # 'source' to force the call to _set_src
-                        # 'value' needed if value is changed in copy(), want to see the new_value
-                        vals['source'] = old_wo_lang[name]
-                        vals['value'] = new_wo_lang[name]
+                        # the value should be the new value (given by copy())
+                        vals['value'] = new_val
                     Translation.create(vals)
 
     @api.multi