From 98a105fe693dd693d8b928e76d6c2eb6dba3d9e7 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Fri, 14 Jun 2013 11:01:53 +0000
Subject: [PATCH] hydra-build: Give a nicer error message if the derivation is
 gone

---
 src/script/hydra-build | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/script/hydra-build b/src/script/hydra-build
index 2137ec33..7117f176 100755
--- a/src/script/hydra-build
+++ b/src/script/hydra-build
@@ -114,6 +114,12 @@ sub doBuild {
 
     my $dependents = [];
 
+    if (!isValidPath($drvPath)) {
+	$buildStatus = 3;
+	$errormsg = "derivation was garbage-collected prior to build";
+	goto done;
+    }
+    
     unless (all { isValidPath($_) } values(%outputs)) {
         $isCachedBuild = 0;