commit 63ffce7e0c01df9c59062951d354c4eeed222a3e
Author: epriestley <git@epriestley.com>
Date:   Thu Aug 29 13:30:38 2019 -0700

    WIP

diff --git a/src/upload/ArcanistFileUploader.php b/src/upload/ArcanistFileUploader.php
index daf4136d..7faad1d0 100644
--- a/src/upload/ArcanistFileUploader.php
+++ b/src/upload/ArcanistFileUploader.php
@@ -262,14 +262,50 @@ final class ArcanistFileUploader extends Phobject {
     foreach ($remaining as $chunk) {
       $data = $file->readBytes($chunk['byteStart'], $chunk['byteEnd']);
 
-      $conduit->callMethodSynchronous(
-        'file.uploadchunk',
-        array(
-          'filePHID' => $file_phid,
-          'byteStart' => $chunk['byteStart'],
-          'dataEncoding' => 'base64',
-          'data' => base64_encode($data),
-        ));
+      $failures = 0;
+      $maximum_failures = 3;
+      while (true) {
+        try {
+          $conduit->callMethodSynchronous(
+            'file.uploadchunk',
+            array(
+              'filePHID' => $file_phid,
+              'byteStart' => $chunk['byteStart'],
+              'dataEncoding' => 'base64',
+              'data' => base64_encode($data),
+            ));
+          break;
+        } catch (HTTPFutureHTTPResponseStatus $ex) {
+          $failures++;
+
+          if ($failures >= $maximum_failures) {
+            throw $ex;
+          }
+
+          // See T13397. If we get status codes which may be temporary, wait
+          // for a moment and retry.
+          switch ($ex->getStatusCode()) {
+            case 429:
+            case 503:
+            case 504:
+              sleep(10);
+              break;
+            default:
+              throw $ex;
+          }
+        } catch (ConduitClientException $ex) {
+          // TODO: This is grotesque, but it's possible that we may upload
+          // a chunk and then suffer some kind of request failure. Treat this
+          // error as a success indicator. The API should not require string
+          // matching against error text.
+          switch ($ex->getMessage()) {
+            case "ERR-CONDUIT-CORE: Chunk has already been uploaded.":
+              break 2;
+            default:
+              throw $ex;
+          }
+        }
+      }
 
       $progress->update(1);
     }