diff --git a/src/applications/calendar/parser/ics/PhutilICSWriter.php b/src/applications/calendar/parser/ics/PhutilICSWriter.php
--- a/src/applications/calendar/parser/ics/PhutilICSWriter.php
+++ b/src/applications/calendar/parser/ics/PhutilICSWriter.php
@@ -184,14 +184,14 @@
     }
 
     $name = $event->getName();
-    if (strlen($name)) {
+    if (phutil_nonempty_string($name)) {
       $properties[] = $this->newTextProperty(
         'SUMMARY',
         $name);
     }
 
     $description = $event->getDescription();
-    if (strlen($description)) {
+    if (phutil_nonempty_string($description)) {
       $properties[] = $this->newTextProperty(
         'DESCRIPTION',
         $description);
diff --git a/src/applications/files/format/__tests__/PhabricatorFileStorageFormatTestCase.php b/src/applications/files/format/__tests__/PhabricatorFileStorageFormatTestCase.php
--- a/src/applications/files/format/__tests__/PhabricatorFileStorageFormatTestCase.php
+++ b/src/applications/files/format/__tests__/PhabricatorFileStorageFormatTestCase.php
@@ -45,6 +45,10 @@
   }
 
   public function testAES256Storage() {
+    if (!function_exists('openssl_encrypt')) {
+      $this->assertSkipped(pht('No OpenSSL extension available.'));
+    }
+
     $engine = new PhabricatorTestStorageEngine();
 
     $key_name = 'test.abcd';
diff --git a/src/applications/nuance/github/NuanceGitHubRawEvent.php b/src/applications/nuance/github/NuanceGitHubRawEvent.php
--- a/src/applications/nuance/github/NuanceGitHubRawEvent.php
+++ b/src/applications/nuance/github/NuanceGitHubRawEvent.php
@@ -164,7 +164,7 @@
     $raw = $this->raw;
 
     $full = idxv($raw, array('repo', 'name'));
-    if (strlen($full)) {
+    if (phutil_nonempty_string($full)) {
       return $full;
     }
 
diff --git a/src/infrastructure/markup/blockrule/PhutilRemarkupListBlockRule.php b/src/infrastructure/markup/blockrule/PhutilRemarkupListBlockRule.php
--- a/src/infrastructure/markup/blockrule/PhutilRemarkupListBlockRule.php
+++ b/src/infrastructure/markup/blockrule/PhutilRemarkupListBlockRule.php
@@ -446,7 +446,7 @@
       }
 
       $start_attr = null;
-      if (ctype_digit($starts_at) && $starts_at > 1) {
+      if (ctype_digit(phutil_string_cast($starts_at)) && $starts_at > 1) {
         $start_attr = hsprintf(' start="%d"', $starts_at);
       }
 
diff --git a/src/infrastructure/markup/markuprule/PhutilRemarkupDocumentLinkRule.php b/src/infrastructure/markup/markuprule/PhutilRemarkupDocumentLinkRule.php
--- a/src/infrastructure/markup/markuprule/PhutilRemarkupDocumentLinkRule.php
+++ b/src/infrastructure/markup/markuprule/PhutilRemarkupDocumentLinkRule.php
@@ -46,7 +46,7 @@
 
     $is_anchor = false;
     if (strncmp($link, '/', 1) == 0) {
-      $base = $engine->getConfig('uri.base');
+      $base = phutil_string_cast($engine->getConfig('uri.base'));
       $base = rtrim($base, '/');
       $link = $base.$link;
     } else if (strncmp($link, '#', 1) == 0) {
@@ -134,7 +134,7 @@
 
   public function markupDocumentLink(array $matches) {
     $uri = trim($matches[1]);
-    $name = trim(idx($matches, 2));
+    $name = trim(idx($matches, 2, ''));
 
     if (!$this->isFlatText($uri)) {
       return $matches[0];