From 12f9129f60651793e319171236e006aecfdc34be Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Sat, 29 Dec 2012 23:21:46 +0100
Subject: [PATCH] nix-build: Support talking to old daemons

Fixes #76.
---
 src/libstore/remote-store.cc | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 8f33b7e5c..0e62914c0 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -441,7 +441,16 @@ void RemoteStore::buildPaths(const PathSet & drvPaths, bool repair)
     if (repair) throw Error("repairing is not supported when building through the Nix daemon");
     openConnection();
     writeInt(wopBuildPaths, to);
-    writeStrings(drvPaths, to);
+    if (GET_PROTOCOL_MINOR(daemonVersion) >= 13)
+        writeStrings(drvPaths, to);
+    else {
+        /* For backwards compatibility with old daemons, strip output
+           identifiers. */
+        PathSet drvPaths2;
+        foreach (PathSet::const_iterator, i, drvPaths)
+            drvPaths2.insert(string(*i, 0, i->find('!')));
+        writeStrings(drvPaths2, to);
+    }
     processStderr();
     readInt(from);
 }