fix crashing previews

models/redner_template.py

@@ -78,7 +78,6 @@
 
     preview = fields.Binary(
         string="Preview",
-        default="New",
         compute="_compute_preview",
         help="This is a preview of the template",
     )
@@ -92,6 +91,7 @@
 
     description = fields.Char(
         string="Description",
+        default="New",
         help="Description of the template",
         readonly=False,
         compute="_compute_template",
@@ -187,4 +187,8 @@
     @api.depends("body", "template_data")
     def _compute_preview(self):
         for record in self:
+            if not record.redner_id:
+                record.preview = False
+                continue
+
             response = self.get_preview(record.redner_id)
@@ -190,4 +194,8 @@
             response = self.get_preview(record.redner_id)
+            if not response:
+                record.preview = False
+                continue
+
             b64 = base64.b64encode(response.content)
             record.preview = b64
 
@@ -197,7 +205,7 @@
             return preview
         except Exception as e:
             logger.error("Failed to get preview of redner template :%s", e)
-            return
+            return False
 
     def _to_odoo_template(self, template):
         """