* Make `derivation' lazy again for performance. It also turns out

  that there are some places in Nixpkgs (php_configurable /
  composableDerivation, it seems) that call `derivation' with
  incorrect arguments (namely, the `name' attribute missing) but get
  away with it because of laziness.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 13ea269fc..34b658ce1 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -104,6 +104,14 @@ static inline void mkBool(Value & v, bool b)
 }
 
 
+static inline void mkThunk(Value & v, Env & env, Expr expr)
+{
+    v.type = tThunk;
+    v.thunk.env = &env;
+    v.thunk.expr = expr;
+}
+
+
 void mkString(Value & v, const char * s);
 void mkString(Value & v, const string & s, const PathSet & context = PathSet());
 void mkPath(Value & v, const char * s);