Feature: Enhanced templating for filename format (#7836)

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/documents/checks.py

@@ -2,12 +2,14 @@ import textwrap
 
 from django.conf import settings
 from django.core.checks import Error
+from django.core.checks import Warning
 from django.core.checks import register
 from django.core.exceptions import FieldError
 from django.db.utils import OperationalError
 from django.db.utils import ProgrammingError
 
 from documents.signals import document_consumer_declaration
+from documents.templating.utils import convert_format_str_to_template_format
 
 
 @register()
@@ -69,3 +71,19 @@ def parser_check(app_configs, **kwargs):
         ]
     else:
         return []
+
+
+@register()
+def filename_format_check(app_configs, **kwargs):
+    if settings.FILENAME_FORMAT:
+        converted_format = convert_format_str_to_template_format(
+            settings.FILENAME_FORMAT,
+        )
+        if converted_format != settings.FILENAME_FORMAT:
+            return [
+                Warning(
+                    f"Filename format {settings.FILENAME_FORMAT} is using the old style, please update to use double curly brackets",
+                    hint=converted_format,
+                ),
+            ]
+    return []