From acd6bddec706e2f180279ca79a0c1a4abac416d6 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 2 Mar 2020 18:15:06 +0100
Subject: [PATCH] Fix derivation primop

---
 src/libexpr/eval.cc    | 14 ++++++++++----
 src/libexpr/eval.hh    |  2 ++
 src/libexpr/primops.cc | 13 ++++++++-----
 3 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 641687f2a..d371a3fb8 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -583,14 +583,20 @@ Value * EvalState::addConstant(const string & name, Value & v)
 {
     Value * v2 = allocValue();
     *v2 = v;
-    staticBaseEnv.vars.emplace_back(symbols.create(name), baseEnvDispl);
-    baseEnv.values[baseEnvDispl++] = v2;
-    string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
-    baseEnv.values[0]->attrs->push_back(Attr(symbols.create(name2), v2));
+    addConstant(name, v2);
     return v2;
 }
 
 
+void EvalState::addConstant(const string & name, Value * v)
+{
+    staticBaseEnv.vars.emplace_back(symbols.create(name), baseEnvDispl);
+    baseEnv.values[baseEnvDispl++] = v;
+    string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
+    baseEnv.values[0]->attrs->push_back(Attr(symbols.create(name2), v));
+}
+
+
 Value * EvalState::addPrimOp(const string & name,
     size_t arity, PrimOpFun primOp)
 {
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index f87dcdd8e..65cf04b57 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -277,6 +277,8 @@ private:
 
     Value * addConstant(const string & name, Value & v);
 
+    void addConstant(const string & name, Value * v);
+
     constexpr static size_t maxPrimOpArity = 3;
 
     Value * addPrimOp(const string & name,
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 9b166d63c..e4107dbe1 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -3725,18 +3725,21 @@ void EvalState::createBaseEnv()
 
     /* Add a wrapper around the derivation primop that computes the
        `drvPath' and `outPath' attributes lazily. */
-    staticBaseEnv.sort();
     sDerivationNix = symbols.create("//builtin/derivation.nix");
-    eval(parse(
-        #include "primops/derivation.nix.gen.hh"
-        , foFile, sDerivationNix, "/", staticBaseEnv), v);
-    addConstant("derivation", v);
+    auto vDerivation = allocValue();
+    addConstant("derivation", vDerivation);
 
     /* Now that we've added all primops, sort the `builtins' set,
        because attribute lookups expect it to be sorted. */
     baseEnv.values[0]->attrs->sort();
 
     staticBaseEnv.sort();
+
+    /* Note: we have to initialize the 'derivation' constant *after*
+       building baseEnv/staticBaseEnv because it uses 'builtins'. */
+    eval(parse(
+        #include "primops/derivation.nix.gen.hh"
+        , foFile, sDerivationNix, "/", staticBaseEnv), *vDerivation);
 }