diff --git a/src/applications/differential/storage/DifferentialDiff.php b/src/applications/differential/storage/DifferentialDiff.php
--- a/src/applications/differential/storage/DifferentialDiff.php
+++ b/src/applications/differential/storage/DifferentialDiff.php
@@ -502,6 +502,10 @@
     return null;
   }
 
+  public function getHarbormasterPublishablePHID() {
+    return $this->getHarbormasterContainerPHID();
+  }
+
   public function getBuildVariables() {
     $results = array();
 
diff --git a/src/applications/differential/storage/DifferentialRevision.php b/src/applications/differential/storage/DifferentialRevision.php
--- a/src/applications/differential/storage/DifferentialRevision.php
+++ b/src/applications/differential/storage/DifferentialRevision.php
@@ -513,6 +513,10 @@
     return $this->getPHID();
   }
 
+  public function getHarbormasterPublishablePHID() {
+    return $this->getPHID();
+  }
+
   public function getBuildVariables() {
     return array();
   }
diff --git a/src/applications/harbormaster/engine/HarbormasterBuildEngine.php b/src/applications/harbormaster/engine/HarbormasterBuildEngine.php
--- a/src/applications/harbormaster/engine/HarbormasterBuildEngine.php
+++ b/src/applications/harbormaster/engine/HarbormasterBuildEngine.php
@@ -497,17 +497,28 @@
       return;
     }
 
-    if (!($object instanceof PhabricatorApplicationTransactionInterface)) {
+    $publish_phid = $object->getHarbormasterPublishablePHID();
+    if (!$publish_phid) {
       return;
     }
 
-    // TODO: Publishing these transactions is causing a race. See T8650.
-    // We shouldn't be publishing to diffs anyway.
-    if ($object instanceof DifferentialDiff) {
+    if ($publish_phid === $object->getPHID()) {
+      $publish = $object;
+    } else {
+      $publish = id(new PhabricatorObjectQuery())
+        ->setViewer($viewer)
+        ->withPHIDs(array($publish_phid))
+        ->executeOne();
+      if (!$publish) {
+        return;
+      }
+    }
+
+    if (!($publish instanceof PhabricatorApplicationTransactionInterface)) {
       return;
     }
 
-    $template = $object->getApplicationTransactionTemplate();
+    $template = $publish->getApplicationTransactionTemplate();
     if (!$template) {
       return;
     }
@@ -526,7 +537,7 @@
     $daemon_source = PhabricatorContentSource::newForSource(
       PhabricatorDaemonContentSource::SOURCECONST);
 
-    $editor = $object->getApplicationTransactionEditor()
+    $editor = $publish->getApplicationTransactionEditor()
       ->setActor($viewer)
       ->setActingAsPHID($harbormaster_phid)
       ->setContentSource($daemon_source)
@@ -534,7 +545,7 @@
       ->setContinueOnMissingFields(true);
 
     $editor->applyTransactions(
-      $object->getApplicationTransactionObject(),
+      $publish->getApplicationTransactionObject(),
       array($template));
   }
 
diff --git a/src/applications/harbormaster/interface/HarbormasterBuildableInterface.php b/src/applications/harbormaster/interface/HarbormasterBuildableInterface.php
--- a/src/applications/harbormaster/interface/HarbormasterBuildableInterface.php
+++ b/src/applications/harbormaster/interface/HarbormasterBuildableInterface.php
@@ -18,6 +18,21 @@
   public function getHarbormasterBuildablePHID();
   public function getHarbormasterContainerPHID();
 
+
+  /**
+   * Get the object PHID which build status should be published to.
+   *
+   * In some cases (like commits), this is the object itself. In other cases,
+   * it is a different object: for example, diffs publish builds to revisions.
+   *
+   * This method can return `null` to disable publishing.
+   *
+   * @return phid|null Build status updates will be published to this object's
+   *  transaction timeline.
+   */
+  public function getHarbormasterPublishablePHID();
+
+
   public function getBuildVariables();
   public function getAvailableBuildVariables();
 
diff --git a/src/applications/harbormaster/storage/HarbormasterBuildable.php b/src/applications/harbormaster/storage/HarbormasterBuildable.php
--- a/src/applications/harbormaster/storage/HarbormasterBuildable.php
+++ b/src/applications/harbormaster/storage/HarbormasterBuildable.php
@@ -317,6 +317,10 @@
     return $this->getContainerPHID();
   }
 
+  public function getHarbormasterPublishablePHID() {
+    return $this->getBuildableObject()->getHarbormasterPublishablePHID();
+  }
+
   public function getBuildVariables() {
     return array();
   }
diff --git a/src/applications/repository/storage/PhabricatorRepositoryCommit.php b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
--- a/src/applications/repository/storage/PhabricatorRepositoryCommit.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
@@ -413,6 +413,10 @@
     return $this->getRepository()->getPHID();
   }
 
+  public function getHarbormasterPublishablePHID() {
+    return $this->getPHID();
+  }
+
   public function getBuildVariables() {
     $results = array();