diff --git a/src/repository/api/git/ArcanistGitAPI.php b/src/repository/api/git/ArcanistGitAPI.php
index 27182235..bd2163f1 100644
--- a/src/repository/api/git/ArcanistGitAPI.php
+++ b/src/repository/api/git/ArcanistGitAPI.php
@@ -745,10 +745,12 @@ final class ArcanistGitAPI extends ArcanistRepositoryAPI {
     }
 
     // If we still didn't succeed, try to find revisions by branch name.
+    $project = $this->getWorkingCopyIdentity()->getProjectID();
     $results = $conduit->callMethodSynchronous(
       'differential.query',
       $query + array(
-        'branches' => array($this->getBranchName()),
+        'branches'          => array($this->getBranchName()),
+        'arcanistProjects'  => array($project),
       ));
 
     return $results;
diff --git a/src/repository/api/subversion/ArcanistSubversionAPI.php b/src/repository/api/subversion/ArcanistSubversionAPI.php
index 9c0c3ae6..6c8fe232 100644
--- a/src/repository/api/subversion/ArcanistSubversionAPI.php
+++ b/src/repository/api/subversion/ArcanistSubversionAPI.php
@@ -534,11 +534,14 @@ EODIFF;
     array $query) {
 
     // We don't have much to go on in SVN, look for revisions that came from
-    // this directory.
+    // this directory and belong to the same project.
 
+    $project = $this->getWorkingCopyIdentity()->getProjectID();
     $results = $conduit->callMethodSynchronous(
       'differential.query',
-      $query);
+      $query + array(
+        'arcanistProjects' => $project,
+      ));
 
     foreach ($results as $key => $result) {
       if ($result['sourcePath'] != $this->getPath()) {