From 18834f77643f5bd1071e1735f23f925d87cce6e5 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 11 Aug 2020 23:44:02 +0000
Subject: [PATCH] Recheck path validity after acquiring lock

It might have changed, and in any event this is how the cod used to work
so let's just keep it.
---
 src/libstore/build.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index c8107c7e8..49042649e 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1547,6 +1547,7 @@ void DerivationGoal::tryToBuild()
        omitted, but that would be less efficient.)  Note that since we
        now hold the locks on the output paths, no other process can
        build this derivation, so no further checks are necessary. */
+    checkPathValidity();
     bool allValid = true;
     for (auto & [_, status] : initialOutputs) {
         if (!status.wanted) continue;