diff --git a/src/applications/diffusion/controller/DiffusionCommitController.php b/src/applications/diffusion/controller/DiffusionCommitController.php
--- a/src/applications/diffusion/controller/DiffusionCommitController.php
+++ b/src/applications/diffusion/controller/DiffusionCommitController.php
@@ -28,7 +28,7 @@
     // If this page is being accessed via "/source/xyz/commit/...", redirect
     // to the canonical URI.
     $has_callsign = strlen($request->getURIData('repositoryCallsign'));
-    $has_id = strlen($request->getURIData('repositoryID'));
+    $has_id = phutil_nonempty_string($request->getURIData('repositoryID'));
     if (!$has_callsign && !$has_id) {
       $canonical_uri = $repository->getCommitURI($commit_identifier);
       return id(new AphrontRedirectResponse())