[3.2.x] Fixed #33628 -- Ignored directories with empty names in autoreloader check for template changes.

Regression in 68357b2ca9e88c40fc00d848799813241be39129.

Backport of 62739b6e2630e37faa68a86a59fad135cc788cd7 from main.

3 files changed, 22 insertions, 3 deletions

diff --git a/django/template/autoreload.py b/django/template/autoreload.py
index 18570b5633..be53693e9d 100644
--- a/django/template/autoreload.py
+++ b/django/template/autoreload.py
@@ -18,7 +18,7 @@ def get_template_directories():
         if not isinstance(backend, DjangoTemplates):
             continue
 
-        items.update(Path.cwd() / to_path(dir) for dir in backend.engine.dirs)
+        items.update(Path.cwd() / to_path(dir) for dir in backend.engine.dirs if dir)
 
         for loader in backend.engine.template_loaders:
             if not hasattr(loader, 'get_dirs'):
@@ -26,7 +26,7 @@ def get_template_directories():
             items.update(
                 Path.cwd() / to_path(directory)
                 for directory in loader.get_dirs()
-                if not is_django_path(directory)
+                if directory and not is_django_path(directory)
             )
     return items
 
diff --git a/docs/releases/3.2.13.txt b/docs/releases/3.2.13.txt
index 53de2645c4..c26a969f95 100644
--- a/docs/releases/3.2.13.txt
+++ b/docs/releases/3.2.13.txt
@@ -4,4 +4,12 @@ Django 3.2.13 release notes
 
 *April 11, 2022*
 
-Django 3.2.13 fixes two security issues with severity "high" in 3.2.12.
+Django 3.2.13 fixes two security issues with severity "high" in
+3.2.12 and a regression in 3.2.4.
+
+Bugfixes
+========
+
+* Fixed a regression in Django 3.2.4 that caused the auto-reloader to no longer
+  detect changes when the ``DIRS`` option of the ``TEMPLATES`` setting
+  contained an empty string (:ticket:`33628`).
diff --git a/tests/template_tests/test_autoreloader.py b/tests/template_tests/test_autoreloader.py
index d6ece4cc6d..0a909bfdd3 100644
--- a/tests/template_tests/test_autoreloader.py
+++ b/tests/template_tests/test_autoreloader.py
@@ -65,6 +65,17 @@ class TemplateReloadTests(SimpleTestCase):
         self.assertEqual(mock_reset.call_count, 2)
 
     @override_settings(
+        TEMPLATES=[
+            {
+                "DIRS": [""],
+                "BACKEND": "django.template.backends.django.DjangoTemplates",
+            }
+        ]
+    )
+    def test_template_dirs_ignore_empty_path(self):
+        self.assertEqual(autoreload.get_template_directories(), set())
+
+    @override_settings(
         TEMPLATES=[{
             'DIRS': [
                 str(ROOT) + '/absolute_str',