diff --git a/scripts/repository/commit_hook.php b/scripts/repository/commit_hook.php
--- a/scripts/repository/commit_hook.php
+++ b/scripts/repository/commit_hook.php
@@ -119,7 +119,7 @@
   exit($err);
 } else if ($repository->isGit() || $repository->isHg()) {
   $username = getenv(DiffusionCommitHookEngine::ENV_USER);
-  if (!phutil_nonempty_string($username)) {
+  if ($username !== false && !phutil_nonempty_string($username)) {
     throw new Exception(
       pht(
         'No Direct Pushes: You are pushing directly to a hosted repository. '.
@@ -181,17 +181,17 @@
 $engine->setOriginalArgv(array_slice($argv, 2));
 
 $remote_address = getenv(DiffusionCommitHookEngine::ENV_REMOTE_ADDRESS);
-if (phutil_nonempty_string($remote_address)) {
+if ($remote_address !== false && phutil_nonempty_string($remote_address)) {
   $engine->setRemoteAddress($remote_address);
 }
 
 $remote_protocol = getenv(DiffusionCommitHookEngine::ENV_REMOTE_PROTOCOL);
-if (phutil_nonempty_string($remote_protocol)) {
+if ($remote_protocol !== false && phutil_nonempty_string($remote_protocol)) {
   $engine->setRemoteProtocol($remote_protocol);
 }
 
 $request_identifier = getenv(DiffusionCommitHookEngine::ENV_REQUEST);
-if (phutil_nonempty_string($request_identifier)) {
+if ($request_identifier !== false && phutil_nonempty_string($request_identifier)) {
   $engine->setRequestIdentifier($request_identifier);
 }