From ff02f5336cd0cff0e97fbcf3c54b5b23827702d6 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 16 Oct 2013 14:51:20 +0200
Subject: [PATCH] Fix a race in registerFailedPath()

Registering the path as failed can fail if another process does the
same thing after the call to hasPathFailed().  This is extremely
unlikely though.
---
 src/libstore/local-store.cc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 15200e842..9f324608c 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -421,7 +421,7 @@ void LocalStore::openDB(bool create)
     stmtInvalidatePath.create(db,
         "delete from ValidPaths where path = ?;");
     stmtRegisterFailedPath.create(db,
-        "insert into FailedPaths (path, time) values (?, ?);");
+        "insert or ignore into FailedPaths (path, time) values (?, ?);");
     stmtHasPathFailed.create(db,
         "select time from FailedPaths where path = ?;");
     stmtQueryFailedPaths.create(db,
@@ -692,7 +692,6 @@ void LocalStore::addReference(unsigned long long referrer, unsigned long long re
 
 void LocalStore::registerFailedPath(const Path & path)
 {
-    if (hasPathFailed(path)) return;
     SQLiteStmtUse use(stmtRegisterFailedPath);
     stmtRegisterFailedPath.bind(path);
     stmtRegisterFailedPath.bind(time(0));