[FIX] core: field display_name should be "" instead of False

This is a followup of #86567, where we change the computation of
display_name to match the values of name_get().  Forcing its value to
False instead of the empty string causes many regressions in frontend
applications like website_blog.

closes odoo/odoo#88438

X-original-commit: d467881f66b11021005005584854f30059971b6c
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

odoo/addons/test_new_api/tests/test_onchange.py

@@ -599,10 +599,11 @@ class TestOnChange(SavepointCaseWithUserDemo):
 
         form = common.Form(self.env['test_new_api.multi.tag'])
         self.assertEqual(form.name, False)
-        self.assertEqual(form.display_name, False)
+        self.assertEqual(form.display_name, "")
 
         record = form.save()
-        self.assertEqual(record.display_name, False)
+        self.assertEqual(record.name, False)
+        self.assertEqual(record.display_name, "")
         self.assertEqual(record.name_get(), [(record.id, "")])
 
 

odoo/models.py

@@ -1835,7 +1835,7 @@ class BaseModel(metaclass=MetaModel):
         """
         names = dict(self.name_get())
         for record in self:
-            record.display_name = names.get(record.id) or False
+            record.display_name = names.get(record.id)
 
     def name_get(self):
         """Returns a textual representation for the records in ``self``, with