From 71bc5b14a00d78dc8a0564858526655dfe653533 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Thu, 8 Oct 2009 11:51:49 +0000
Subject: [PATCH] * Add --fallback to prevent problems with obsolete
 substitutes.

---
 src/script/hydra_build.pl | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/script/hydra_build.pl b/src/script/hydra_build.pl
index 6824ce08..af519a6c 100755
--- a/src/script/hydra_build.pl
+++ b/src/script/hydra_build.pl
@@ -161,8 +161,9 @@ sub doBuild {
         # Run Nix to perform the build, and monitor the stderr output
         # to get notifications about specific build steps, the
         # associated log files, etc.
-        my $cmd = "nix-store --max-silent-time 3600 --keep-going --no-build-output " .
-            "--log-type flat --print-build-trace --realise $drvPath " .
+        my $cmd = "nix-store --realise $drvPath " .
+            "--max-silent-time 3600 --keep-going --fallback " .
+            "--no-build-output --log-type flat --print-build-trace " .
             "--add-root " . gcRootFor $outPath . " 2>&1";
 
         my $buildStepNr = $build->buildsteps->find({},