3 files changed, 17 insertions, 6 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index fadfb3b530e1..c10177223e5a 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -181,7 +181,7 @@ EvalState::EvalState()
     searchPathInsertionPoint = searchPath.end();
     Strings paths = tokenizeString(getEnv("NIX_PATH", ""), ":");
     foreach (Strings::iterator, i, paths) addToSearchPath(*i);
-    addToSearchPath("nix=" + nixDataDir + "/nix/corepkgs");
+    addToSearchPath("nix=" + settings.nixDataDir + "/nix/corepkgs");
     searchPathInsertionPoint = searchPath.begin();
 
     createBaseEnv();
@@ -1091,7 +1091,7 @@ string EvalState::coerceToString(Value & v, PathSet & context,
         if (srcToStore[path] != "")
             dstPath = srcToStore[path];
         else {
-            dstPath = readOnlyMode
+            dstPath = settings.readOnlyMode
                 ? computeStorePathForPath(path).first
                 : store->addToStore(path);
             srcToStore[path] = dstPath;
diff --git a/src/libexpr/get-drvs.hh b/src/libexpr/get-drvs.hh
index 879dc8dbb45d..25d8baa559b2 100644
--- a/src/libexpr/get-drvs.hh
+++ b/src/libexpr/get-drvs.hh
@@ -31,6 +31,8 @@ private:
 
     bool metaInfoRead;
     MetaInfo meta;
+
+    bool failed; // set if we get an AssertionError
     
 public:
     string name;
@@ -40,7 +42,7 @@ public:
     /* !!! make this private */
     Bindings * attrs;
 
-    DrvInfo() : metaInfoRead(false), attrs(0) { };
+    DrvInfo() : metaInfoRead(false), failed(false), attrs(0) { };
 
     string queryDrvPath(EvalState & state) const;
     string queryOutPath(EvalState & state) const;
@@ -58,6 +60,9 @@ public:
     }
 
     void setMetaInfo(const MetaInfo & meta);
+
+    void setFailed() { failed = true; };
+    bool hasFailed() { return failed; };
 };
 
 
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index cb09d8ff0120..d3809e6984a0 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -51,6 +51,12 @@ static void prim_import(EvalState & state, Value * * args, Value & v)
                 % path % ctx);
         if (isDerivation(ctx))
             try {
+                /* For performance, prefetch all substitute info. */
+                PathSet willBuild, willSubstitute, unknown;
+                unsigned long long downloadSize, narSize;
+                queryMissing(*store, singleton<PathSet>(ctx),
+                    willBuild, willSubstitute, unknown, downloadSize, narSize);
+                  
                 /* !!! If using a substitute, we only need to fetch
                    the selected output of this derivation. */
                 store->buildPaths(singleton<PathSet>(ctx));
@@ -617,7 +623,7 @@ static void prim_toFile(EvalState & state, Value * * args, Value & v)
         refs.insert(path);
     }
     
-    Path storePath = readOnlyMode
+    Path storePath = settings.readOnlyMode
         ? computeStorePathForText(name, contents, refs)
         : store->addTextToStore(name, contents, refs);
 
@@ -681,7 +687,7 @@ static void prim_filterSource(EvalState & state, Value * * args, Value & v)
 
     FilterFromExpr filter(state, *args[0]);
 
-    Path dstPath = readOnlyMode
+    Path dstPath = settings.readOnlyMode
         ? computeStorePathForPath(path, true, htSHA256, filter).first
         : store->addToStore(path, true, htSHA256, filter);
 
@@ -1134,7 +1140,7 @@ void EvalState::createBaseEnv()
     mkInt(v, time(0));
     addConstant("__currentTime", v);
 
-    mkString(v, thisSystem.c_str());
+    mkString(v, settings.thisSystem.c_str());
     addConstant("__currentSystem", v);
 
     // Miscellaneous