From a807edfae8428bf426ee6ae849a7a24d74d39202 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 3 Oct 2012 11:20:16 -0400
Subject: [PATCH] Handle repairing paths that are in build-chroot-dirs

---
 src/libstore/build.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 6c40b6686..b62991dff 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1875,6 +1875,13 @@ void DerivationGoal::startBuilder()
             }
         }
 
+        /* If we're repairing, it's possible that we're rebuilding a
+           path that is in settings.dirsInChroot (typically the
+           dependencies of /bin/sh).  Throw them out. */
+        if (repair)
+            foreach (DerivationOutputs::iterator, i, drv.outputs)
+                dirsInChroot.erase(i->second.path);
+
 #else
         throw Error("chroot builds are not supported on this platform");
 #endif