Accept supported template directory mutations

Author: joshuadavidthomas

crates/djls-project/src/settings/extraction.rs

@@ -1346,7 +1346,10 @@ fn setting_accepts_mutation(setting: KnownSetting, mutation: &PythonMutation) ->
         KnownSetting::Templates => {
             matches!(
                 mutation.operation,
-                PythonMutationOperation::Append | PythonMutationOperation::Extend
+                PythonMutationOperation::Append
+                    | PythonMutationOperation::Extend
+                    | PythonMutationOperation::Insert
+                    | PythonMutationOperation::Remove
             ) && matches!(mutation.path.as_slice(), [PythonMutationPathSegment::Index(_), PythonMutationPathSegment::Key(key)] if key == "DIRS")
         }
         KnownSetting::StaticUrl | KnownSetting::StaticRoot | KnownSetting::StaticFilesDirs => false,

crates/djls-project/tests/settings.rs

@@ -1552,6 +1552,31 @@ fn template_dirs_resolve_settings_module_file() {
     assert_eq!(dirs, vec![Utf8PathBuf::from("/proj/templates")]);
 }
 
+#[test]
+fn template_dirs_follow_supported_nested_insert_and_remove_mutations() {
+    let mut db = TestDatabase::new();
+    let project = project_with_settings(
+        &mut db,
+        "myproject.settings",
+        &[(
+            "/proj/myproject/settings.py",
+            "TEMPLATES = [{'BACKEND': 'django.template.backends.django.DjangoTemplates', 'DIRS': ['/proj/first', '/proj/removed'], 'APP_DIRS': False}]
+TEMPLATES[0]['DIRS'].insert(1, '/proj/inserted')
+TEMPLATES[0]['DIRS'].remove('/proj/removed')",
+        )],
+    );
+
+    let dirs = complete_template_dirs(&db, project);
+
+    assert_eq!(
+        dirs,
+        [
+            Utf8PathBuf::from("/proj/first"),
+            Utf8PathBuf::from("/proj/inserted"),
+        ]
+    );
+}
+
 #[test]
 fn template_dirs_merge_equivalent_explicit_backend_branches() {
     let mut db = TestDatabase::new();

crates/djls-project/tests/settings_extraction.rs

@@ -2892,6 +2892,23 @@ fn nested_template_dirs_append_and_extend_are_supported() {
     assert_eq!(dirs[3]["value"]["resolved"], "/d");
 }
 
+#[test]
+fn nested_template_dirs_insert_and_remove_are_supported() {
+    let settings = extract(
+        "TEMPLATES = [{'BACKEND': 'django.template.backends.django.DjangoTemplates', 'DIRS': ['/a', '/c', '/removed']}]
+TEMPLATES[0]['DIRS'].insert(1, '/b')
+TEMPLATES[0]['DIRS'].remove('/removed')",
+    );
+    let cases = cases(&settings, "/templates/cases");
+    let dirs = cases[0]["known"]["backends"][0]["dirs"].as_array().unwrap();
+
+    assert_eq!(cases.len(), 1, "{settings:#}");
+    assert_eq!(dirs.len(), 3, "{settings:#}");
+    assert_eq!(dirs[0]["value"]["resolved"], "/a");
+    assert_eq!(dirs[1]["value"]["resolved"], "/b");
+    assert_eq!(dirs[2]["value"]["resolved"], "/c");
+}
+
 #[test]
 fn nested_template_dirs_mutation_updates_all_correlated_equal_lists() {
     let settings = extract(