diff --git a/src/applications/auth/provider/PhabricatorOAuth1AuthProvider.php b/src/applications/auth/provider/PhabricatorOAuth1AuthProvider.php
index ef1991e8d7..b1590b9c82 100644
--- a/src/applications/auth/provider/PhabricatorOAuth1AuthProvider.php
+++ b/src/applications/auth/provider/PhabricatorOAuth1AuthProvider.php
@@ -21,7 +21,7 @@ abstract class PhabricatorOAuth1AuthProvider
     $config = $this->getProviderConfig();
     $adapter->setConsumerKey($config->getProperty(self::PROPERTY_CONSUMER_KEY));
     $secret = $config->getProperty(self::PROPERTY_CONSUMER_SECRET);
-    if (strlen($secret)) {
+    if (phutil_nonempty_string($secret)) {
       $adapter->setConsumerSecret(new PhutilOpaqueEnvelope($secret));
     }
     $adapter->setCallbackURI(PhabricatorEnv::getURI($this->getLoginURI()));
diff --git a/src/applications/cache/management/PhabricatorCacheManagementPurgeWorkflow.php b/src/applications/cache/management/PhabricatorCacheManagementPurgeWorkflow.php
index cfe42c918b..37de525a02 100644
--- a/src/applications/cache/management/PhabricatorCacheManagementPurgeWorkflow.php
+++ b/src/applications/cache/management/PhabricatorCacheManagementPurgeWorkflow.php
@@ -27,11 +27,11 @@ final class PhabricatorCacheManagementPurgeWorkflow
     $is_all = $args->getArg('all');
     $key_list = $args->getArg('caches');
 
-    if ($is_all && strlen($key_list)) {
+    if ($is_all && phutil_nonempty_string($key_list)) {
       throw new PhutilArgumentUsageException(
         pht(
           'Specify either "--all" or "--caches", not both.'));
-    } else if (!$is_all && !strlen($key_list)) {
+    } else if (!$is_all && !phutil_nonempty_string($key_list)) {
       throw new PhutilArgumentUsageException(
         pht(
           'Select caches to purge with "--all" or "--caches". Available '.
diff --git a/src/applications/daemon/event/PhabricatorDaemonEventListener.php b/src/applications/daemon/event/PhabricatorDaemonEventListener.php
index 41324cc9c9..a17bab77af 100644
--- a/src/applications/daemon/event/PhabricatorDaemonEventListener.php
+++ b/src/applications/daemon/event/PhabricatorDaemonEventListener.php
@@ -63,9 +63,12 @@ final class PhabricatorDaemonEventListener extends PhabricatorEventListener {
     // TODO: This is a bit awkward for historical reasons, clean it up after
     // removing Conduit.
     $message = $event->getValue('message');
+
     $context = $event->getValue('context');
-    if (strlen($context) && $context !== $message) {
-      $message = "({$context}) {$message}";
+    if (phutil_nonempty_scalar($context)) {
+      if ($context !== $message) {
+        $message = "({$context}) {$message}";
+      }
     }
 
     $type = $event->getValue('type');
diff --git a/src/applications/drydock/management/DrydockManagementLeaseWorkflow.php b/src/applications/drydock/management/DrydockManagementLeaseWorkflow.php
index 08f33c6b5f..7890b27d28 100644
--- a/src/applications/drydock/management/DrydockManagementLeaseWorkflow.php
+++ b/src/applications/drydock/management/DrydockManagementLeaseWorkflow.php
@@ -41,7 +41,7 @@ final class DrydockManagementLeaseWorkflow
     }
 
     $until = $args->getArg('until');
-    if (strlen($until)) {
+    if (phutil_nonempty_string($until)) {
       $until = strtotime($until);
       if ($until <= 0) {
         throw new PhutilArgumentUsageException(
@@ -52,7 +52,7 @@ final class DrydockManagementLeaseWorkflow
     }
 
     $attributes_file = $args->getArg('attributes');
-    if (strlen($attributes_file)) {
+    if (phutil_nonempty_string($attributes_file)) {
       if ($attributes_file == '-') {
         echo tsprintf(
           "%s\n",
diff --git a/src/applications/policy/query/PhabricatorPolicyQuery.php b/src/applications/policy/query/PhabricatorPolicyQuery.php
index 018007db28..9bd6ba5994 100644
--- a/src/applications/policy/query/PhabricatorPolicyQuery.php
+++ b/src/applications/policy/query/PhabricatorPolicyQuery.php
@@ -290,6 +290,10 @@ final class PhabricatorPolicyQuery
   }
 
   public static function isSpecialPolicy($identifier) {
+    if ($identifier === null) {
+      return true;
+    }
+
     if (self::isObjectPolicy($identifier)) {
       return true;
     }
diff --git a/src/applications/repository/storage/PhabricatorRepository.php b/src/applications/repository/storage/PhabricatorRepository.php
index 3e0c4a45e7..0ac6687ef8 100644
--- a/src/applications/repository/storage/PhabricatorRepository.php
+++ b/src/applications/repository/storage/PhabricatorRepository.php
@@ -193,7 +193,7 @@ final class PhabricatorRepository extends PhabricatorRepositoryDAO
 
   public function getMonogram() {
     $callsign = $this->getCallsign();
-    if (strlen($callsign)) {
+    if (phutil_nonempty_string($callsign)) {
       return "r{$callsign}";
     }
 
diff --git a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
index 8abb5178d5..a470ef0c9b 100644
--- a/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
+++ b/src/applications/transactions/storage/PhabricatorApplicationTransaction.php
@@ -605,7 +605,7 @@ abstract class PhabricatorApplicationTransaction
           }
 
           if (!is_array($old)) {
-            if (!strlen($old)) {
+            if ($old === '' || $old === null) {
               return true;
             }
 
diff --git a/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldPHIDs.php b/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldPHIDs.php
index 78c8caa5a9..a96ebefda1 100644
--- a/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldPHIDs.php
+++ b/src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldPHIDs.php
@@ -256,6 +256,10 @@ abstract class PhabricatorStandardCustomFieldPHIDs
   }
 
   protected function decodeValue($value) {
+    if ($value === null) {
+      return array();
+    }
+
     $value = json_decode($value);
     if (!is_array($value)) {
       $value = array();
diff --git a/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php b/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php
index 34a8e1813c..1cf2b4b9ea 100644
--- a/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php
+++ b/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php
@@ -369,7 +369,7 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
 
     $this->setLimit($limit + 1);
 
-    if (strlen($pager->getAfterID())) {
+    if (phutil_nonempty_string($pager->getAfterID())) {
       $this->setExternalCursorString($pager->getAfterID());
     } else if ($pager->getBeforeID()) {
       $this->setExternalCursorString($pager->getBeforeID());