1 files changed, 46 insertions, 21 deletions

diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 66173cdaf05f..ca7766487cd4 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -356,27 +356,31 @@ static void prim_derivationStrict(EvalState & state, Value * * args, Value & v)
            inputs to ensure that they are available when the builder
            runs. */
         if (path.at(0) == '=') {
-            path = string(path, 1);
-            PathSet refs; computeFSClosure(*store, path, refs);
+            /* !!! This doesn't work if readOnlyMode is set. */
+            PathSet refs; computeFSClosure(*store, string(path, 1), refs);
             foreach (PathSet::iterator, j, refs) {
                 drv.inputSrcs.insert(*j);
                 if (isDerivation(*j))
-                    drv.inputDrvs[*j] = singleton<StringSet>("out");
+                    drv.inputDrvs[*j] = store->queryDerivationOutputNames(*j);
             }
         }
 
         /* See prim_unsafeDiscardOutputDependency. */
-        bool useDrvAsSrc = false;
-        if (path.at(0) == '~') {
-            path = string(path, 1);
-            useDrvAsSrc = true;
+        else if (path.at(0) == '~')
+            drv.inputSrcs.insert(string(path, 1));
+
+        /* Handle derivation outputs of the form ‘!<name>!<path>’. */
+        else if (path.at(0) == '!') {
+            size_t index = path.find("!", 1);
+            drv.inputDrvs[string(path, index + 1)].insert(string(path, 1, index - 1));
         }
 
-        assert(isStorePath(path));
+        /* Handle derivation contexts returned by
+           ‘builtins.storePath’. */
+        else if (isDerivation(path))
+            drv.inputDrvs[path] = store->queryDerivationOutputNames(path);
 
-        debug(format("derivation uses `%1%'") % path);
-        if (!useDrvAsSrc && isDerivation(path))
-            drv.inputDrvs[path] = singleton<StringSet>("out");
+        /* Otherwise it's a source file. */
         else
             drv.inputSrcs.insert(path);
     }
@@ -450,7 +454,7 @@ static void prim_derivationStrict(EvalState & state, Value * * args, Value & v)
         /* The output path of an output X is ‘<X>Path’,
            e.g. ‘outPath’. */
         mkString(*state.allocAttr(v, state.symbols.create(i->first + "Path")),
-            i->second.path, singleton<PathSet>(drvPath));
+            i->second.path, singleton<PathSet>("!" + i->first + "!" + drvPath));
     }
     v.attrs->sort();
 }
@@ -1042,15 +1046,6 @@ void EvalState::createBaseEnv()
     addPrimOp("__getEnv", 1, prim_getEnv);
     addPrimOp("__trace", 2, prim_trace);
 
-    // Derivations
-    addPrimOp("derivationStrict", 1, prim_derivationStrict);
-
-    /* Add a wrapper around the derivation primop that computes the
-       `drvPath' and `outPath' attributes lazily. */
-    string s = "attrs: let res = derivationStrict attrs; in attrs // { drvPath = res.drvPath; outPath = res.outPath; type = \"derivation\"; }";
-    mkThunk_(v, parseExprFromString(s, "/"));
-    addConstant("derivation", v);
-
     // Paths
     addPrimOp("__toPath", 1, prim_toPath);
     addPrimOp("__storePath", 1, prim_storePath);
@@ -1099,6 +1094,36 @@ void EvalState::createBaseEnv()
     addPrimOp("__parseDrvName", 1, prim_parseDrvName);
     addPrimOp("__compareVersions", 2, prim_compareVersions);
 
+    // Derivations
+    addPrimOp("derivationStrict", 1, prim_derivationStrict);
+
+    /* Add a wrapper around the derivation primop that computes the
+       `drvPath' and `outPath' attributes lazily. */
+    string s = "attrs: \
+      let \
+        strict = derivationStrict attrs; \
+        attrValues = attrs: \
+          map (name: builtins.getAttr name attrs) (builtins.attrNames attrs); \
+        outputToAttrListElement = output: \
+          { \
+            name = output; \
+            value = attrs // { \
+              outPath = builtins.getAttr (output + \"Path\") strict; \
+              drvPath = strict.drvPath; \
+              type = \"derivation\"; \
+              currentOutput = output; \
+            } // outputsAttrs // { all = allList; }; \
+          }; \
+        outputsList = if attrs ? outputs then \
+          map outputToAttrListElement attrs.outputs else \
+          [ (outputToAttrListElement \"out\") ]; \
+        outputsAttrs = builtins.listToAttrs outputsList; \
+        allList = attrValues outputsAttrs; \
+        head = if attrs ? outputs then builtins.head attrs.outputs else \"out\"; \
+      in builtins.getAttr head outputsAttrs";
+    mkThunk_(v, parseExprFromString(s, "/"));
+    addConstant("derivation", v);
+
     /* Now that we've added all primops, sort the `builtins' attribute
        set, because attribute lookups expect it to be sorted. */
     baseEnv.values[0]->attrs->sort();