Fix autoreload regression for empty template DIRS (swev-id: django__django-15572)

django/template/autoreload.py

@@ -17,16 +17,20 @@ def get_template_directories():
         if not isinstance(backend, DjangoTemplates):
             continue
 
-        items.update(cwd / to_path(dir) for dir in backend.engine.dirs)
+        for directory in backend.engine.dirs:
+            if isinstance(directory, str) and directory.strip() == "":
+                continue
+            items.add(cwd / to_path(directory))
 
         for loader in backend.engine.template_loaders:
             if not hasattr(loader, "get_dirs"):
                 continue
-            items.update(
-                cwd / to_path(directory)
-                for directory in loader.get_dirs()
-                if not is_django_path(directory)
-            )
+            for directory in loader.get_dirs():
+                if isinstance(directory, str) and directory.strip() == "":
+                    continue
+                if is_django_path(directory):
+                    continue
+                items.add(cwd / to_path(directory))
     return items
 
 

tests/template_tests/test_autoreloader_empty_dirs.py

@@ -0,0 +1,20 @@
+from pathlib import Path
+
+from django.template import autoreload
+from django.test import SimpleTestCase, override_settings
+
+
+class TemplateAutoreloadEmptyDirsTests(SimpleTestCase):
+    @override_settings(
+        TEMPLATES=[
+            {
+                "BACKEND": "django.template.backends.django.DjangoTemplates",
+                "DIRS": [""],
+                "APP_DIRS": True,
+                "OPTIONS": {},
+            }
+        ]
+    )
+    def test_empty_string_dirs_are_ignored(self):
+        directories = autoreload.get_template_directories()
+        self.assertNotIn(Path.cwd(), directories)