Add --include-build-refs to `nix path-info' command

src/libcmd/command.cc

@@ -3,6 +3,7 @@
 #include "local-fs-store.hh"
 #include "derivations.hh"
 #include "nixexpr.hh"
+#include "eval.hh"
 #include "profiles.hh"
 
 #include <nlohmann/json.hpp>
@@ -79,6 +80,13 @@ StorePathsCommand::StorePathsCommand(bool recursive)
         .category = installablesCategory,
         .handler = {&all, true},
     });
+
+    addFlag({
+        .longName = "include-build-refs",
+        .description = "Include build-time references of specified path closure.",
+        .category = installablesCategory,
+        .handler = {&includeBuildRefs, true},
+    });
 }
 
 void StorePathsCommand::run(ref<Store> store)
@@ -93,15 +101,38 @@ void StorePathsCommand::run(ref<Store> store)
     }
 
     else {
+        if (!recursive && includeBuildRefs)
+            throw UsageError("--include-build-refs requires --recursive");
+
         for (auto & p : toStorePaths(store, realiseMode, operateOn, installables))
             storePaths.push_back(p);
 
         if (recursive) {
+            if (includeBuildRefs) {
+                for (auto & i : installables) {
+                    for (auto & b : i->toBuildables()) {
+                        std::visit(overloaded {
+                                [&](BuildableOpaque bo) {
+                                    auto info = store->queryPathInfo(bo.path);
+                                    if (info->deriver)
+                                        storePaths.push_back(*info->deriver);
+                                    else
+                                        throw UsageError("Cannot find build references for '%s' without a derivation path", store->printStorePath(bo.path));
+                                },
+                                [&](BuildableFromDrv bfd) {
+                                    storePaths.push_back(bfd.drvPath);
+                                },
+                            }, b);
+                    }
+                }
+            }
+
             StorePathSet closure;
-            store->computeFSClosure(StorePathSet(storePaths.begin(), storePaths.end()), closure, false, false);
+            store->computeFSClosure(StorePathSet(storePaths.begin(), storePaths.end()), closure, false, includeBuildRefs);
             storePaths.clear();
             for (auto & p : closure)
-                storePaths.push_back(p);
+                if (!p.isDerivation())
+                    storePaths.push_back(p);
         }
     }
 

src/libcmd/command.hh

@@ -148,6 +148,8 @@ private:
     bool recursive = false;
     bool all = false;
 
+    bool includeBuildRefs = false;
+
 protected:
 
     Realise realiseMode = Realise::Derivation;

src/libcmd/installables.hh

@@ -25,6 +25,10 @@ struct BuildableFromDrv {
     StorePath drvPath;
     std::map<std::string, std::optional<StorePath>> outputs;
     nlohmann::json toJSON(ref<Store> store) const;
+
+    std::string what() {
+        return fmt("%s", outputs.at("out") ? outputs.at("out")->name() : "unknown");
+    }
 };
 
 typedef std::variant<