diff --git a/src/applications/files/controller/PhabricatorFileDataController.php b/src/applications/files/controller/PhabricatorFileDataController.php
--- a/src/applications/files/controller/PhabricatorFileDataController.php
+++ b/src/applications/files/controller/PhabricatorFileDataController.php
@@ -29,7 +29,7 @@
     $request_kind = $request->getURIData('kind');
     $is_download = ($request_kind === 'download');
 
-    if (!strlen($alt) || $main_domain == $alt_domain) {
+    if (!phutil_nonempty_string($alt) || $main_domain == $alt_domain) {
       // No alternate domain.
       $should_redirect = false;
       $is_alternate_domain = false;
diff --git a/src/applications/search/field/PhabricatorSearchDateField.php b/src/applications/search/field/PhabricatorSearchDateField.php
--- a/src/applications/search/field/PhabricatorSearchDateField.php
+++ b/src/applications/search/field/PhabricatorSearchDateField.php
@@ -17,7 +17,7 @@
   }
 
   protected function validateControlValue($value) {
-    if (!strlen($value)) {
+    if (!phutil_nonempty_string($value)) {
       return;
     }
 
@@ -32,7 +32,7 @@
   }
 
   protected function parseDateTime($value) {
-    if (!strlen($value)) {
+    if (!phutil_nonempty_string($value)) {
       return null;
     }
 
diff --git a/src/view/layout/AphrontSideNavFilterView.php b/src/view/layout/AphrontSideNavFilterView.php
--- a/src/view/layout/AphrontSideNavFilterView.php
+++ b/src/view/layout/AphrontSideNavFilterView.php
@@ -97,7 +97,7 @@
       ->setName($name)
       ->setType($type);
 
-    if (strlen($icon)) {
+    if (phutil_nonempty_string($icon)) {
       $item->setIcon($icon);
     }