diff --git a/src/browse/query/ArcanistBrowseObjectNameURIHardpointQuery.php b/src/browse/query/ArcanistBrowseObjectNameURIHardpointQuery.php
--- a/src/browse/query/ArcanistBrowseObjectNameURIHardpointQuery.php
+++ b/src/browse/query/ArcanistBrowseObjectNameURIHardpointQuery.php
@@ -15,7 +15,7 @@
     $token_set = array();
     foreach ($refs as $key => $ref) {
       $token = $ref->getToken();
-      if (!strlen($token)) {
+      if ($token === null || !strlen($token)) {
         continue;
       }
 
diff --git a/src/lint/linter/ArcanistCppcheckLinter.php b/src/lint/linter/ArcanistCppcheckLinter.php
--- a/src/lint/linter/ArcanistCppcheckLinter.php
+++ b/src/lint/linter/ArcanistCppcheckLinter.php
@@ -35,7 +35,7 @@
     list($stdout) = execx('%C --version', $this->getExecutableCommand());
 
     $matches = array();
-    $regex = '/^Cppcheck (?P<version>\d+\.\d+)$/';
+    $regex = '/^Cppcheck (?P<version>\d+\.\d+(\.\d+)?)$/';
     if (preg_match($regex, $stdout, $matches)) {
       return $matches['version'];
     } else {
diff --git a/src/lint/linter/ArcanistScriptAndRegexLinter.php b/src/lint/linter/ArcanistScriptAndRegexLinter.php
--- a/src/lint/linter/ArcanistScriptAndRegexLinter.php
+++ b/src/lint/linter/ArcanistScriptAndRegexLinter.php
@@ -204,7 +204,7 @@
    */
   public function lintPath($path) {
     $output = idx($this->output, $path);
-    if (!strlen($output)) {
+    if ($output === null || !strlen($output)) {
       // No output, but it exited 0, so just move on.
       return;
     }
@@ -338,7 +338,7 @@
     }
 
     $line = idx($match, 'line');
-    if (strlen($line)) {
+    if ($line !== null && strlen($line)) {
       $line = (int)$line;
       if (!$line) {
         $line = 1;
@@ -376,7 +376,11 @@
       'disabled' => ArcanistLintSeverity::SEVERITY_DISABLED,
     );
 
-    $severity_name = strtolower(idx($match, 'severity'));
+    $severity_name = idx($match, 'severity');
+    if ($severity_name === null || !strlen($severity_name)) {
+      return ArcanistLintSeverity::SEVERITY_ERROR;
+    }
+    $severity_name = strtolower($severity_name);
 
     foreach ($map as $name => $severity) {
       if (!empty($match[$name])) {
diff --git a/src/ref/ArcanistRefView.php b/src/ref/ArcanistRefView.php
--- a/src/ref/ArcanistRefView.php
+++ b/src/ref/ArcanistRefView.php
@@ -98,12 +98,14 @@
     // TODO: This should truncate based on console display width, not
     // glyphs, but there's currently no "setMaximumConsoleCharacterWidth()".
 
-    $title = id(new PhutilUTF8StringTruncator())
-      ->setMaximumGlyphs($usable_width)
-      ->truncateString($title);
+    if ($title !== null && strlen($title)) {
+      $title = id(new PhutilUTF8StringTruncator())
+        ->setMaximumGlyphs($usable_width)
+        ->truncateString($title);
+    }
 
     if ($object_name !== null) {
-      if (strlen($title)) {
+      if ($title !== null && strlen($title)) {
         $display_text = tsprintf('**%s** %s', $object_name, $title);
       } else {
         $display_text = tsprintf('**%s**', $object_name);
diff --git a/src/repository/api/ArcanistGitAPI.php b/src/repository/api/ArcanistGitAPI.php
--- a/src/repository/api/ArcanistGitAPI.php
+++ b/src/repository/api/ArcanistGitAPI.php
@@ -1143,7 +1143,7 @@
 
   public function hasLocalCommit($commit) {
     try {
-      if (!$this->getCanonicalRevisionName($commit)) {
+      if ($commit === null || !$this->getCanonicalRevisionName($commit)) {
         return false;
       }
     } catch (CommandException $exception) {
diff --git a/src/workflow/ArcanistWorkflow.php b/src/workflow/ArcanistWorkflow.php
--- a/src/workflow/ArcanistWorkflow.php
+++ b/src/workflow/ArcanistWorkflow.php
@@ -480,7 +480,7 @@
       // token-based authentication. Use that instead of all the certificate
       // stuff.
       $token = idx($credentials, 'token');
-      if (strlen($token)) {
+      if ($token !== null && strlen($token)) {
         $conduit = $this->getConduit();
 
         $conduit->setConduitToken($token);
@@ -2245,7 +2245,7 @@
     $map = $this->getModernCommonDictionary($map);
 
     $details = idx($map, 'userData');
-    if (strlen($details)) {
+    if ($details !== null && strlen($details)) {
       $map['details'] = (string)$details;
     }
     unset($map['userData']);