daemon: Substitute queries return immediately when substitutes are disabled.

Reported by Federico Beffa <beffa@ieee.org>
at <https://lists.gnu.org/archive/html/guix-devel/2016-05/msg00928.html>.

* nix/libstore/local-store.cc (LocalStore::querySubstitutablePaths)
(LocalStore::querySubstitutablePathInfos): Return when
'settings.useSubstitutes' is false.
* tests/store.scm ("references/substitutes missing reference info"):
Make sure to return #f on failure.
* tests/store.scm ("substitutable-path-info when substitutes are turned off"):
("substitutable-paths when substitutes are turned off"): New tests.

1 files changed, 5 insertions, 0 deletions

diff --git a/nix/libstore/local-store.cc b/nix/libstore/local-store.cc
index 1eed0ca77f..347e8a703f 100644
--- a/nix/libstore/local-store.cc
+++ b/nix/libstore/local-store.cc
@@ -1213,6 +1213,9 @@ template<class T> T LocalStore::getIntLineFromSubstituter(RunningSubstituter & r
 PathSet LocalStore::querySubstitutablePaths(const PathSet & paths)
 {
     PathSet res;
+
+    if (!settings.useSubstitutes) return res;
+
     foreach (Paths::iterator, i, settings.substituters) {
         if (res.size() == paths.size()) break;
         RunningSubstituter & run(runningSubstituters[*i]);
@@ -1239,6 +1242,8 @@ PathSet LocalStore::querySubstitutablePaths(const PathSet & paths)
 void LocalStore::querySubstitutablePathInfos(const Path & substituter,
     PathSet & paths, SubstitutablePathInfos & infos)
 {
+    if (!settings.useSubstitutes) return;
+
     RunningSubstituter & run(runningSubstituters[substituter]);
     startSubstituter(substituter, run);
     if (run.disabled) return;