From 794e4ab475399363982f5602ed1ba12bf0be4343 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 20 Sep 2016 17:25:12 +0200
Subject: [PATCH] Fix "Promise already satisfied" error

---
 src/libstore/http-binary-cache-store.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/libstore/http-binary-cache-store.cc b/src/libstore/http-binary-cache-store.cc
index 60728de04..74ae7a4d1 100644
--- a/src/libstore/http-binary-cache-store.cc
+++ b/src/libstore/http-binary-cache-store.cc
@@ -86,7 +86,9 @@ protected:
                     std::rethrow_exception(exc);
                 } catch (DownloadError & e) {
                     if (e.error == Downloader::NotFound || e.error == Downloader::Forbidden)
-                        success(0);
+                        return success(0);
+                    failure(exc);
+                } catch (...) {
                     failure(exc);
                 }
             });