8 files changed, 172 insertions, 8 deletions
diff --git a/src/nix/command.cc b/src/nix/command.cc
index f69c56896567..0f6bb294b38c 100644
--- a/src/nix/command.cc
+++ b/src/nix/command.cc
@@ -100,9 +100,21 @@ void StoreCommand::run()
     run(getStore());
 }
 
-StorePathsCommand::StorePathsCommand()
+StorePathsCommand::StorePathsCommand(bool recursive)
+    : recursive(recursive)
 {
-    mkFlag('r', "recursive", "apply operation to closure of the specified paths", &recursive);
+    if (recursive)
+        mkFlag()
+            .longName("no-recursive")
+            .description("apply operation to specified paths only")
+            .set(&this->recursive, false);
+    else
+        mkFlag()
+            .longName("recursive")
+            .shortName('r')
+            .description("apply operation to closure of the specified paths")
+            .set(&this->recursive, true);
+
     mkFlag(0, "all", "apply operation to the entire store", &all);
 }
 
diff --git a/src/nix/command.hh b/src/nix/command.hh
index 182b01ef92e3..bf897f620db6 100644
--- a/src/nix/command.hh
+++ b/src/nix/command.hh
@@ -141,7 +141,7 @@ private:
 
 public:
 
-    StorePathsCommand();
+    StorePathsCommand(bool recursive = false);
 
     using StoreCommand::run;
 
@@ -207,4 +207,8 @@ PathSet toStorePaths(ref<Store> store, RealiseMode mode,
 Path toStorePath(ref<Store> store, RealiseMode mode,
     std::shared_ptr<Installable> installable);
 
+PathSet toDerivations(ref<Store> store,
+    std::vector<std::shared_ptr<Installable>> installables,
+    bool useDeriver = false);
+
 }
diff --git a/src/nix/copy.cc b/src/nix/copy.cc
index 8d7c6a0e8e4c..071ac3890aa9 100644
--- a/src/nix/copy.cc
+++ b/src/nix/copy.cc
@@ -17,6 +17,7 @@ struct CmdCopy : StorePathsCommand
     SubstituteFlag substitute = NoSubstitute;
 
     CmdCopy()
+        : StorePathsCommand(true)
     {
         mkFlag(0, "from", "store-uri", "URI of the source Nix store", &srcUri);
         mkFlag(0, "to", "store-uri", "URI of the destination Nix store", &dstUri);
diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index 76df05fa32d2..c83d6316d3f3 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -267,7 +267,9 @@ Buildables toBuildables(ref<Store> store, RealiseMode mode,
                     outputNames.insert(output.first);
                 pathsToBuild.insert(
                     b.drvPath + "!" + concatStringsSep(",", outputNames));
-            }
+            } else
+                for (auto & output : b.outputs)
+                    pathsToBuild.insert(output.second);
             buildables.push_back(std::move(b));
         }
     }
@@ -303,6 +305,30 @@ Path toStorePath(ref<Store> store, RealiseMode mode,
     return *paths.begin();
 }
 
+PathSet toDerivations(ref<Store> store,
+    std::vector<std::shared_ptr<Installable>> installables, bool useDeriver)
+{
+    PathSet drvPaths;
+
+    for (auto & i : installables)
+        for (auto & b : i->toBuildables()) {
+            if (b.drvPath.empty()) {
+                if (!useDeriver)
+                    throw Error("argument '%s' did not evaluate to a derivation", i->what());
+                for (auto & output : b.outputs) {
+                    auto derivers = store->queryValidDerivers(output.second);
+                    if (derivers.empty())
+                        throw Error("'%s' does not have a known deriver", i->what());
+                    // FIXME: use all derivers?
+                    drvPaths.insert(*derivers.begin());
+                }
+            } else
+                drvPaths.insert(b.drvPath);
+        }
+
+    return drvPaths;
+}
+
 void InstallablesCommand::prepare()
 {
     installables = parseInstallables(*this, getStore(), _installables, useDefaultInstallables());
diff --git a/src/nix/progress-bar.cc b/src/nix/progress-bar.cc
index 0c42fe5cc136..76138b2cce28 100644
--- a/src/nix/progress-bar.cc
+++ b/src/nix/progress-bar.cc
@@ -165,7 +165,7 @@ public:
 
         if (type == actQueryPathInfo) {
             auto name = storePathToName(getS(fields, 0));
-            i->s = fmt("querying about " ANSI_BOLD "%s" ANSI_NORMAL " on %s", name, getS(fields, 1));
+            i->s = fmt("querying " ANSI_BOLD "%s" ANSI_NORMAL " on %s", name, getS(fields, 1));
         }
 
         if ((type == actDownload && hasAncestor(*state, actCopyPath, parent))
diff --git a/src/nix/run.cc b/src/nix/run.cc
index c72ede99c1c2..2f93ca351502 100644
--- a/src/nix/run.cc
+++ b/src/nix/run.cc
@@ -130,6 +130,8 @@ struct CmdRun : InstallablesCommand
 
         stopProgressBar();
 
+        restoreSignals();
+
         /* If this is a diverted store (i.e. its "logical" location
            (typically /nix/store) differs from its "physical" location
            (e.g. /home/eelco/nix/store), then run the command in a
diff --git a/src/nix/show-derivation.cc b/src/nix/show-derivation.cc
new file mode 100644
index 000000000000..ee94fded364f
--- /dev/null
+++ b/src/nix/show-derivation.cc
@@ -0,0 +1,119 @@
+// FIXME: integrate this with nix path-info?
+
+#include "command.hh"
+#include "common-args.hh"
+#include "store-api.hh"
+#include "archive.hh"
+#include "json.hh"
+#include "derivations.hh"
+
+using namespace nix;
+
+struct CmdShowDerivation : InstallablesCommand
+{
+    bool recursive = false;
+
+    CmdShowDerivation()
+    {
+        mkFlag()
+            .longName("recursive")
+            .shortName('r')
+            .description("include the dependencies of the specified derivations")
+            .set(&recursive, true);
+    }
+
+    std::string name() override
+    {
+        return "show-derivation";
+    }
+
+    std::string description() override
+    {
+        return "show the contents of a store derivation";
+    }
+
+    Examples examples() override
+    {
+        return {
+            Example{
+                "To show the store derivation that results from evaluating the Hello package:",
+                "nix show-derivation nixpkgs.hello"
+            },
+            Example{
+                "To show the full derivation graph (if available) that produced your NixOS system:",
+                "nix show-derivation -r /run/current-system"
+            },
+        };
+    }
+
+    void run(ref<Store> store) override
+    {
+        auto drvPaths = toDerivations(store, installables, true);
+
+        if (recursive) {
+            PathSet closure;
+            store->computeFSClosure(drvPaths, closure);
+            drvPaths = closure;
+        }
+
+        {
+
+        JSONObject jsonRoot(std::cout, true);
+
+        for (auto & drvPath : drvPaths) {
+            if (!isDerivation(drvPath)) continue;
+
+            auto drvObj(jsonRoot.object(drvPath));
+
+            auto drv = readDerivation(drvPath);
+
+            {
+                auto outputsObj(drvObj.object("outputs"));
+                for (auto & output : drv.outputs) {
+                    auto outputObj(outputsObj.object(output.first));
+                    outputObj.attr("path", output.second.path);
+                    if (output.second.hash != "") {
+                        outputObj.attr("hashAlgo", output.second.hashAlgo);
+                        outputObj.attr("hash", output.second.hash);
+                    }
+                }
+            }
+
+            {
+                auto inputsList(drvObj.list("inputSrcs"));
+                for (auto & input : drv.inputSrcs)
+                    inputsList.elem(input);
+            }
+
+            {
+                auto inputDrvsObj(drvObj.object("inputDrvs"));
+                for (auto & input : drv.inputDrvs) {
+                    auto inputList(inputDrvsObj.list(input.first));
+                    for (auto & outputId : input.second)
+                        inputList.elem(outputId);
+                }
+            }
+
+            drvObj.attr("platform", drv.platform);
+            drvObj.attr("builder", drv.builder);
+
+            {
+                auto argsList(drvObj.list("args"));
+                for (auto & arg : drv.args)
+                    argsList.elem(arg);
+            }
+
+            {
+                auto envObj(drvObj.object("env"));
+                for (auto & var : drv.env)
+                    envObj.attr(var.first, var.second);
+            }
+        }
+
+        }
+
+        std::cout << "\n";
+    }
+};
+
+static RegisterCommand r1(make_ref<CmdShowDerivation>());
diff --git a/src/nix/why-depends.cc b/src/nix/why-depends.cc
index a90d07ed26ee..17e0595ae887 100644
--- a/src/nix/why-depends.cc
+++ b/src/nix/why-depends.cc
@@ -156,7 +156,7 @@ struct CmdWhyDepends : SourceExprCommand
 
         printNode = [&](Node & node, const string & firstPad, const string & tailPad) {
             assert(node.dist != inf);
-            std::cerr << fmt("%s%s%s%s" ANSI_NORMAL "\n",
+            std::cout << fmt("%s%s%s%s" ANSI_NORMAL "\n",
                 firstPad,
                 node.visited ? "\e[38;5;244m" : "",
                 firstPad != "" ? "=> " : "",
@@ -209,7 +209,7 @@ struct CmdWhyDepends : SourceExprCommand
                     for (auto & hash : hashes) {
                         auto pos = contents.find(hash);
                         if (pos != std::string::npos) {
-                            size_t margin = 16;
+                            size_t margin = 32;
                             auto pos2 = pos >= margin ? pos - margin : 0;
                             hits[hash].emplace_back(fmt("%s: …%s…\n",
                                     p2,
@@ -244,7 +244,7 @@ struct CmdWhyDepends : SourceExprCommand
 
                 for (auto & hit : hits[hash]) {
                     bool first = hit == *hits[hash].begin();
-                    std::cerr << tailPad
+                    std::cout << tailPad
                               << (first ? (last ? treeLast : treeConn) : (last ? treeNull : treeLine))
                               << hit;
                     if (!all) break;