From f58f51f38007f8bfb1089c3b4c88b6e66da15f39 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Tue, 24 Aug 2010 11:45:44 +0000
Subject: [PATCH] * Handle the unlikely case where a derivation has no
 dependencies at   all.

---
 src/libstore/build.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 6f0276244..5617eccf1 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -887,7 +887,10 @@ void DerivationGoal::outputsSubstituted()
     foreach (PathSet::iterator, i, drv.inputSrcs)
         addWaitee(worker.makeSubstitutionGoal(*i));
 
-    state = &DerivationGoal::inputsRealised;
+    if (waitees.empty()) /* to prevent hang (no wake-up event) */
+        inputsRealised();
+    else
+        state = &DerivationGoal::inputsRealised;
 }