Make clear that StorePathWithOutputs is a deprecated type

- Add a comment

- Put `OutputsSpec` in a different header (First part of #6815)

- Make a few stray uses of it in new code use `DerivedPath` instead.

src/libcmd/installables.hh

@@ -2,7 +2,7 @@
 
 #include "util.hh"
 #include "path.hh"
-#include "path-with-outputs.hh"
+#include "outputs-spec.hh"
 #include "derived-path.hh"
 #include "eval.hh"
 #include "store-api.hh"
@@ -20,7 +20,7 @@ namespace eval_cache { class EvalCache; class AttrCursor; }
 
 struct App
 {
-    std::vector<StorePathWithOutputs> context;
+    std::vector<DerivedPath> context;
     Path program;
     // FIXME: add args, sandbox settings, metadata, ...
 };

src/libexpr/flake/flakeref.hh

@@ -3,7 +3,7 @@
 #include "types.hh"
 #include "hash.hh"
 #include "fetchers.hh"
-#include "path-with-outputs.hh"
+#include "outputs-spec.hh"
 
 #include <variant>
 

src/libmain/shared.hh

@@ -39,7 +39,6 @@ void printVersion(const std::string & programName);
 void printGCWarning();
 
 class Store;
-struct StorePathWithOutputs;
 
 void printMissing(
     ref<Store> store,

src/libstore/outputs-spec.cc

@@ -0,0 +1,61 @@
+#include "outputs-spec.hh"
+#include "nlohmann/json.hpp"
+
+#include <regex>
+
+namespace nix {
+
+std::pair<std::string, OutputsSpec> parseOutputsSpec(const std::string & s)
+{
+    static std::regex regex(R"((.*)\^((\*)|([a-z]+(,[a-z]+)*)))");
+
+    std::smatch match;
+    if (!std::regex_match(s, match, regex))
+        return {s, DefaultOutputs()};
+
+    if (match[3].matched)
+        return {match[1], AllOutputs()};
+
+    return {match[1], tokenizeString<OutputNames>(match[4].str(), ",")};
+}
+
+std::string printOutputsSpec(const OutputsSpec & outputsSpec)
+{
+    if (std::get_if<DefaultOutputs>(&outputsSpec))
+        return "";
+
+    if (std::get_if<AllOutputs>(&outputsSpec))
+        return "^*";
+
+    if (auto outputNames = std::get_if<OutputNames>(&outputsSpec))
+        return "^" + concatStringsSep(",", *outputNames);
+
+    assert(false);
+}
+
+void to_json(nlohmann::json & json, const OutputsSpec & outputsSpec)
+{
+    if (std::get_if<DefaultOutputs>(&outputsSpec))
+        json = nullptr;
+
+    else if (std::get_if<AllOutputs>(&outputsSpec))
+        json = std::vector<std::string>({"*"});
+
+    else if (auto outputNames = std::get_if<OutputNames>(&outputsSpec))
+        json = *outputNames;
+}
+
+void from_json(const nlohmann::json & json, OutputsSpec & outputsSpec)
+{
+    if (json.is_null())
+        outputsSpec = DefaultOutputs();
+    else {
+        auto names = json.get<OutputNames>();
+        if (names == OutputNames({"*"}))
+            outputsSpec = AllOutputs();
+        else
+            outputsSpec = names;
+    }
+}
+
+}

src/libstore/outputs-spec.hh

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <variant>
+
+#include "util.hh"
+
+#include "nlohmann/json_fwd.hpp"
+
+namespace nix {
+
+typedef std::set<std::string> OutputNames;
+
+struct AllOutputs {
+    bool operator < (const AllOutputs & _) const { return false; }
+};
+
+struct DefaultOutputs {
+    bool operator < (const DefaultOutputs & _) const { return false; }
+};
+
+typedef std::variant<DefaultOutputs, AllOutputs, OutputNames> OutputsSpec;
+
+/* Parse a string of the form 'prefix^output1,...outputN' or
+   'prefix^*', returning the prefix and the outputs spec. */
+std::pair<std::string, OutputsSpec> parseOutputsSpec(const std::string & s);
+
+std::string printOutputsSpec(const OutputsSpec & outputsSpec);
+
+void to_json(nlohmann::json &, const OutputsSpec &);
+void from_json(const nlohmann::json &, OutputsSpec &);
+
+}

src/libstore/path-with-outputs.cc

@@ -1,6 +1,5 @@
 #include "path-with-outputs.hh"
 #include "store-api.hh"
-#include "nlohmann/json.hpp"
 
 #include <regex>
 
@@ -71,57 +70,4 @@ StorePathWithOutputs followLinksToStorePathWithOutputs(const Store & store, std:
     return StorePathWithOutputs { store.followLinksToStorePath(path), std::move(outputs) };
 }
 
-std::pair<std::string, OutputsSpec> parseOutputsSpec(const std::string & s)
-{
-    static std::regex regex(R"((.*)\^((\*)|([a-z]+(,[a-z]+)*)))");
-
-    std::smatch match;
-    if (!std::regex_match(s, match, regex))
-        return {s, DefaultOutputs()};
-
-    if (match[3].matched)
-        return {match[1], AllOutputs()};
-
-    return {match[1], tokenizeString<OutputNames>(match[4].str(), ",")};
-}
-
-std::string printOutputsSpec(const OutputsSpec & outputsSpec)
-{
-    if (std::get_if<DefaultOutputs>(&outputsSpec))
-        return "";
-
-    if (std::get_if<AllOutputs>(&outputsSpec))
-        return "^*";
-
-    if (auto outputNames = std::get_if<OutputNames>(&outputsSpec))
-        return "^" + concatStringsSep(",", *outputNames);
-
-    assert(false);
-}
-
-void to_json(nlohmann::json & json, const OutputsSpec & outputsSpec)
-{
-    if (std::get_if<DefaultOutputs>(&outputsSpec))
-        json = nullptr;
-
-    else if (std::get_if<AllOutputs>(&outputsSpec))
-        json = std::vector<std::string>({"*"});
-
-    else if (auto outputNames = std::get_if<OutputNames>(&outputsSpec))
-        json = *outputNames;
-}
-
-void from_json(const nlohmann::json & json, OutputsSpec & outputsSpec)
-{
-    if (json.is_null())
-        outputsSpec = DefaultOutputs();
-    else {
-        auto names = json.get<OutputNames>();
-        if (names == OutputNames({"*"}))
-            outputsSpec = AllOutputs();
-        else
-            outputsSpec = names;
-    }
-}
-
 }

src/libstore/path-with-outputs.hh

@@ -1,13 +1,18 @@
 #pragma once
 
-#include <variant>
-
 #include "path.hh"
 #include "derived-path.hh"
 #include "nlohmann/json_fwd.hpp"
 
 namespace nix {
 
+/* This is a deprecated old type just for use by the old CLI, and older
+   versions of the RPC protocols. In new code don't use it; you want
+   `DerivedPath` instead.
+
+   `DerivedPath` is better because it handles more cases, and does so more
+   explicitly without devious punning tricks.
+*/
 struct StorePathWithOutputs
 {
     StorePath path;
@@ -33,25 +38,4 @@ StorePathWithOutputs parsePathWithOutputs(const Store & store, std::string_view
 
 StorePathWithOutputs followLinksToStorePathWithOutputs(const Store & store, std::string_view pathWithOutputs);
 
-typedef std::set<std::string> OutputNames;
-
-struct AllOutputs {
-    bool operator < (const AllOutputs & _) const { return false; }
-};
-
-struct DefaultOutputs {
-    bool operator < (const DefaultOutputs & _) const { return false; }
-};
-
-typedef std::variant<DefaultOutputs, AllOutputs, OutputNames> OutputsSpec;
-
-/* Parse a string of the form 'prefix^output1,...outputN' or
-   'prefix^*', returning the prefix and the outputs spec. */
-std::pair<std::string, OutputsSpec> parseOutputsSpec(const std::string & s);
-
-std::string printOutputsSpec(const OutputsSpec & outputsSpec);
-
-void to_json(nlohmann::json &, const OutputsSpec &);
-void from_json(const nlohmann::json &, OutputsSpec &);
-
 }

src/libstore/tests/outputs-spec.cc

@@ -1,4 +1,4 @@
-#include "path-with-outputs.hh"
+#include "outputs-spec.hh"
 
 #include <gtest/gtest.h>
 

src/nix/app.cc

@@ -79,9 +79,19 @@ UnresolvedApp Installable::toApp(EvalState & state)
     if (type == "app") {
         auto [program, context] = cursor->getAttr("program")->getStringWithContext();
 
-        std::vector<StorePathWithOutputs> context2;
-        for (auto & [path, name] : context)
-            context2.push_back({path, {name}});
+        std::vector<DerivedPath> context2;
+        for (auto & [path, name] : context) {
+            context2.push_back(name != "" || path.isDerivation()
+                ? (DerivedPath) DerivedPath::Built {
+                    .drvPath = path,
+                    .outputs = name != ""
+                        ? StringSet { name }
+                        : StringSet { },
+                }
+                : (DerivedPath) DerivedPath::Opaque {
+                    .path = path,
+                });
+        }
 
         return UnresolvedApp{App {
             .context = std::move(context2),
@@ -105,7 +115,10 @@ UnresolvedApp Installable::toApp(EvalState & state)
             : DrvName(name).name;
         auto program = outPath + "/bin/" + mainProgram;
         return UnresolvedApp { App {
-            .context = { { drvPath, {outputName} } },
+            .context = { DerivedPath::Built {
+                .drvPath = drvPath,
+                .outputs = {outputName},
+            } },
             .program = program,
         }};
     }
@@ -123,7 +136,7 @@ App UnresolvedApp::resolve(ref<Store> evalStore, ref<Store> store)
 
     for (auto & ctxElt : unresolved.context)
         installableContext.push_back(
-            std::make_shared<InstallableDerivedPath>(store, ctxElt.toDerivedPath()));
+            std::make_shared<InstallableDerivedPath>(store, ctxElt));
 
     auto builtContext = Installable::build(evalStore, store, Realise::Outputs, installableContext);
     res.program = resolveString(*store, unresolved.program, builtContext);

src/nix/develop.cc

@@ -3,7 +3,7 @@
 #include "common-args.hh"
 #include "shared.hh"
 #include "store-api.hh"
-#include "path-with-outputs.hh"
+#include "outputs-spec.hh"
 #include "derivations.hh"
 #include "progress-bar.hh"
 #include "run.hh"

src/nix/flake.cc

@@ -7,7 +7,7 @@
 #include "get-drvs.hh"
 #include "store-api.hh"
 #include "derivations.hh"
-#include "path-with-outputs.hh"
+#include "outputs-spec.hh"
 #include "attr-path.hh"
 #include "fetchers.hh"
 #include "registry.hh"