InputScheme::fetch(): Return a StorePath instead of a Tree

src/libfetchers/fetchers.cc

@@ -124,15 +124,13 @@ std::pair<Tree, Input> Input::fetch(ref<Store> store) const
             debug("using substituted/cached input '%s' in '%s'",
                 to_string(), store->printStorePath(storePath));
 
-            auto actualPath = store->toRealPath(storePath);
+            return {Tree { .actualPath = store->toRealPath(storePath), .storePath = std::move(storePath) }, *this};
-
-            return {fetchers::Tree(std::move(actualPath), std::move(storePath)), *this};
         } catch (Error & e) {
             debug("substitution of input '%s' failed: %s", to_string(), e.what());
         }
     }
 
-    auto [tree, input] = [&]() -> std::pair<Tree, Input> {
+    auto [storePath, input] = [&]() -> std::pair<StorePath, Input> {
         try {
             return scheme->fetch(store, *this);
         } catch (Error & e) {
@@ -141,8 +139,10 @@ std::pair<Tree, Input> Input::fetch(ref<Store> store) const
         }
     }();
 
-    if (tree.actualPath == "")
+    Tree tree {
-        tree.actualPath = store->toRealPath(tree.storePath);
+        .actualPath = store->toRealPath(storePath),
+        .storePath = storePath,
+    };
 
     auto narHash = store->queryPathInfo(tree.storePath)->narHash;
     input.attrs.insert_or_assign("narHash", narHash.to_string(SRI, true));

src/libfetchers/fetchers.hh

@@ -16,7 +16,6 @@ struct Tree
 {
     Path actualPath;
     StorePath storePath;
-    Tree(Path && actualPath, StorePath && storePath) : actualPath(actualPath), storePath(std::move(storePath)) {}
 };
 
 struct InputScheme;
@@ -131,7 +130,7 @@ struct InputScheme
 
     virtual void markChangedFile(const Input & input, std::string_view file, std::optional<std::string> commitMsg);
 
-    virtual std::pair<Tree, Input> fetch(ref<Store> store, const Input & input) = 0;
+    virtual std::pair<StorePath, Input> fetch(ref<Store> store, const Input & input) = 0;
 };
 
 void registerInputScheme(std::shared_ptr<InputScheme> && fetcher);

src/libfetchers/git.cc

@@ -172,7 +172,7 @@ struct GitInputScheme : InputScheme
         return {isLocal, isLocal ? url.path : url.base};
     }
 
-    std::pair<Tree, Input> fetch(ref<Store> store, const Input & _input) override
+    std::pair<StorePath, Input> fetch(ref<Store> store, const Input & _input) override
     {
         Input input(_input);
 
@@ -197,17 +197,14 @@ struct GitInputScheme : InputScheme
         };
 
         auto makeResult = [&](const Attrs & infoAttrs, StorePath && storePath)
-            -> std::pair<Tree, Input>
+            -> std::pair<StorePath, Input>
         {
             assert(input.getRev());
             assert(!_input.getRev() || _input.getRev() == input.getRev());
             if (!shallow)
                 input.attrs.insert_or_assign("revCount", getIntAttr(infoAttrs, "revCount"));
             input.attrs.insert_or_assign("lastModified", getIntAttr(infoAttrs, "lastModified"));
-            return {
+            return {std::move(storePath), input};
-                Tree(store->toRealPath(storePath), std::move(storePath)),
-                input
-            };
         };
 
         if (input.getRev()) {
@@ -285,10 +282,7 @@ struct GitInputScheme : InputScheme
                     "lastModified",
                     haveCommits ? std::stoull(runProgram("git", true, { "-C", actualUrl, "log", "-1", "--format=%ct", "--no-show-signature", "HEAD" })) : 0);
 
-                return {
+                return {std::move(storePath), input};
-                    Tree(store->toRealPath(storePath), std::move(storePath)),
-                    input
-                };
             }
         }
 

src/libfetchers/github.cc

@@ -180,7 +180,7 @@ struct GitArchiveInputScheme : InputScheme
 
     virtual DownloadUrl getDownloadUrl(const Input & input) const = 0;
 
-    std::pair<Tree, Input> fetch(ref<Store> store, const Input & _input) override
+    std::pair<StorePath, Input> fetch(ref<Store> store, const Input & _input) override
     {
         Input input(_input);
 
@@ -199,10 +199,7 @@ struct GitArchiveInputScheme : InputScheme
 
         if (auto res = getCache()->lookup(store, immutableAttrs)) {
             input.attrs.insert_or_assign("lastModified", getIntAttr(res->first, "lastModified"));
-            return {
+            return {std::move(res->second), input};
-                Tree(store->toRealPath(res->second), std::move(res->second)),
-                input
-            };
         }
 
         auto url = getDownloadUrl(input);
@@ -221,7 +218,7 @@ struct GitArchiveInputScheme : InputScheme
             tree.storePath,
             true);
 
-        return {std::move(tree), input};
+        return {std::move(tree.storePath), input};
     }
 };
 

src/libfetchers/indirect.cc

@@ -94,7 +94,7 @@ struct IndirectInputScheme : InputScheme
         return input;
     }
 
-    std::pair<Tree, Input> fetch(ref<Store> store, const Input & input) override
+    std::pair<StorePath, Input> fetch(ref<Store> store, const Input & input) override
     {
         throw Error("indirect input '%s' cannot be fetched directly", input.to_string());
     }

src/libfetchers/mercurial.cc

@@ -143,7 +143,7 @@ struct MercurialInputScheme : InputScheme
         return {isLocal, isLocal ? url.path : url.base};
     }
 
-    std::pair<Tree, Input> fetch(ref<Store> store, const Input & _input) override
+    std::pair<StorePath, Input> fetch(ref<Store> store, const Input & _input) override
     {
         Input input(_input);
 
@@ -193,10 +193,7 @@ struct MercurialInputScheme : InputScheme
 
                 auto storePath = store->addToStore(input.getName(), actualUrl, FileIngestionMethod::Recursive, htSHA256, filter);
 
-                return {
+                return {std::move(storePath), input};
-                    Tree(store->toRealPath(storePath), std::move(storePath)),
-                    input
-                };
             }
         }
 
@@ -212,15 +209,12 @@ struct MercurialInputScheme : InputScheme
         };
 
         auto makeResult = [&](const Attrs & infoAttrs, StorePath && storePath)
-            -> std::pair<Tree, Input>
+            -> std::pair<StorePath, Input>
         {
             assert(input.getRev());
             assert(!_input.getRev() || _input.getRev() == input.getRev());
             input.attrs.insert_or_assign("revCount", getIntAttr(infoAttrs, "revCount"));
-            return {
+            return {std::move(storePath), input};
-                Tree(store->toRealPath(storePath), std::move(storePath)),
-                input
-            };
         };
 
         if (input.getRev()) {

src/libfetchers/path.cc

@@ -80,7 +80,7 @@ struct PathInputScheme : InputScheme
         // nothing to do
     }
 
-    std::pair<Tree, Input> fetch(ref<Store> store, const Input & input) override
+    std::pair<StorePath, Input> fetch(ref<Store> store, const Input & input) override
     {
         std::string absPath;
         auto path = getStrAttr(input.attrs, "path");
@@ -115,10 +115,7 @@ struct PathInputScheme : InputScheme
             // FIXME: try to substitute storePath.
             storePath = store->addToStore("source", absPath);
 
-        return {
+        return {std::move(*storePath), input};
-            Tree(store->toRealPath(*storePath), std::move(*storePath)),
-            input
-        };
     }
 };
 

src/libfetchers/tarball.cc

@@ -126,7 +126,7 @@ std::pair<Tree, time_t> downloadTarball(
 
     if (cached && !cached->expired)
         return {
-            Tree(store->toRealPath(cached->storePath), std::move(cached->storePath)),
+            Tree { .actualPath = store->toRealPath(cached->storePath), .storePath = std::move(cached->storePath) },
             getIntAttr(cached->infoAttrs, "lastModified")
         };
 
@@ -163,7 +163,7 @@ std::pair<Tree, time_t> downloadTarball(
         immutable);
 
     return {
-        Tree(store->toRealPath(*unpackedStorePath), std::move(*unpackedStorePath)),
+        Tree { .actualPath = store->toRealPath(*unpackedStorePath), .storePath = std::move(*unpackedStorePath) },
         lastModified,
     };
 }
@@ -225,10 +225,10 @@ struct TarballInputScheme : InputScheme
         return true;
     }
 
-    std::pair<Tree, Input> fetch(ref<Store> store, const Input & input) override
+    std::pair<StorePath, Input> fetch(ref<Store> store, const Input & input) override
     {
         auto tree = downloadTarball(store, getStrAttr(input.attrs, "url"), input.getName(), false).first;
-        return {std::move(tree), input};
+        return {std::move(tree.storePath), input};
     }
 };