Add warning for discontinued settings

Author: fsbraun

djangocms_frontend/apps.py

@@ -1,11 +1,39 @@
 from django import apps
+from django.core.checks import Warning, register
 
 
 class DjangocmsFrontendConfig(apps.AppConfig):
     name = "djangocms_frontend"
-    verbose_name = "DjangoCMS Frontend"
+    verbose_name = "django CMS Frontend"
 
     def ready(self):
         from .component_pool import setup
 
+        register(check_settings)
         setup()
+
+
+def check_settings(*args, **kwargs):
+    from django.conf import settings
+
+    warnings = []
+
+    if hasattr(settings, "DJANGOCMS_FRONTEND_MINIMUM_INPUT_LENGTH"):
+        warnings.append(Warning(
+            "The DJANGOCMS_FRONTEND_MINIMUM_INPUT_LENGTH setting was removed in djangocms-frontend 2.\n"
+            "Use DJANGOCMS_LINK_MINIMUM_INPUT_LENGTH instead.",
+            "This message disappears after removing the DJANGOCMS_FRONTEND_MINIMUM_INPUT_LENGTH from your project's "
+            "settings.\n",
+            id="djangocms_frontend.W001",
+            obj="settings.DJANGOCMS_FRONTEND_MINIMUM_INPUT_LENGTH",
+        ))
+    if hasattr(settings, "DJANGOCMS_FRONTEND_LINK_MODELS"):
+        warnings.append(Warning(
+            "The DJANGOCMS_FRONTEND_LINK_MODELS setting was removed in djangocms-frontend 2.\n"
+            "djangocms-frontend 2 uses linkable models from djangocms-link. See "
+            "https://github.com/django-cms/djangocms-link#django-cms-link for more info.",
+            "This message disappears after removing the DJANGOCMS_FRONTEND_LINK_MODELS from your project's settings.\n",
+            id="djangocms_frontend.W002",
+            obj="settings.DJANGOCMS_FRONTEND_LINK_MODELS",
+        ))
+    return warnings