Merge remote-tracking branch 'upstream/master' into path-info

.github/workflows/test.yml

@@ -12,8 +12,6 @@ jobs:
     - uses: actions/checkout@v2
       with:
         fetch-depth: 0
-    - uses: cachix/install-nix-action@v10
+    - uses: cachix/install-nix-action@v11
-      with:
-        skip_adding_nixpkgs_channel: true
     #- run: nix flake check
     - run: nix-build -A checks.$(if [[ `uname` = Linux ]]; then echo x86_64-linux; else echo x86_64-darwin; fi)

README.md

@@ -9,7 +9,7 @@ for more details.
 
 ## Installation
 
-On Linux and macOS the easiest way to Install Nix is to run the following shell command
+On Linux and macOS the easiest way to install Nix is to run the following shell command
 (as a user other than root):
 
 ```console

doc/manual/generate-options.nix

@@ -13,7 +13,12 @@ concatStrings (map
       then "*empty*"
       else if isBool option.value
       then (if option.value then "`true`" else "`false`")
-      else "`" + toString option.value + "`") + "\n\n"
+      else
+        # n.b. a StringMap value type is specified as a string, but
+        # this shows the value type.  The empty stringmap is "null" in
+        # JSON, but that converts to "{ }" here.
+        (if isAttrs option.value then "`\"\"`"
+         else "`" + toString option.value + "`")) + "\n\n"
     + (if option.aliases != []
        then "    **Deprecated alias:** " + (concatStringsSep ", " (map (s: "`${s}`") option.aliases)) + "\n\n"
        else "")

doc/manual/src/hacking.md

@@ -39,17 +39,17 @@ To build Nix itself in this shell:
 
 ```console
 [nix-shell]$ ./bootstrap.sh
-[nix-shell]$ ./configure $configureFlags --prefix=$(pwd)/inst
+[nix-shell]$ ./configure $configureFlags --prefix=$(pwd)/outputs/out
 [nix-shell]$ make -j $NIX_BUILD_CORES
 ```
 
-To install it in `$(pwd)/inst` and test it:
+To install it in `$(pwd)/outputs` and test it:
 
 ```console
 [nix-shell]$ make install
-[nix-shell]$ make installcheck
+[nix-shell]$ make installcheck -j $NIX_BUILD_CORES
-[nix-shell]$ ./inst/bin/nix --version
+[nix-shell]$ ./outputs/out/bin/nix --version
-nix (Nix) 2.4
+nix (Nix) 3.0
 ```
 
 To run a functional test:
@@ -58,6 +58,12 @@ To run a functional test:
 make tests/test-name-should-auto-complete.sh.test
 ```
 
+To run the unit-tests for C++ code:
+
+```
+make check
+```
+
 If you have a flakes-enabled Nix you can replace:
 
 ```console

scripts/install-nix-from-closure.sh

@@ -2,6 +2,8 @@
 
 set -e
 
+umask 0022
+
 dest="/nix"
 self="$(dirname "$0")"
 nix="@nix@"

scripts/install.in

@@ -10,6 +10,8 @@ oops() {
     exit 1
 }
 
+umask 0022
+
 tmpDir="$(mktemp -d -t nix-binary-tarball-unpack.XXXXXXXXXX || \
           oops "Can't create temporary directory for downloading the Nix binary tarball")"
 cleanup() {

src/libexpr/flake/flake.cc

@@ -48,17 +48,17 @@ static std::tuple<fetchers::Tree, FlakeRef, FlakeRef> fetchOrSubstituteTree(
                 resolvedRef = originalRef.resolve(state.store);
                 auto fetchedResolved = lookupInFlakeCache(flakeCache, originalRef);
                 if (!fetchedResolved) fetchedResolved.emplace(resolvedRef.fetchTree(state.store));
-                flakeCache.push_back({resolvedRef, fetchedResolved.value()});
+                flakeCache.push_back({resolvedRef, *fetchedResolved});
-                fetched.emplace(fetchedResolved.value());
+                fetched.emplace(*fetchedResolved);
             }
             else {
                 throw Error("'%s' is an indirect flake reference, but registry lookups are not allowed", originalRef);
             }
         }
-        flakeCache.push_back({originalRef, fetched.value()});
+        flakeCache.push_back({originalRef, *fetched});
     }
 
-    auto [tree, lockedRef] = fetched.value();
+    auto [tree, lockedRef] = *fetched;
 
     debug("got tree '%s' from '%s'",
         state.store->printStorePath(tree.storePath), lockedRef);
@@ -247,7 +247,7 @@ Flake getFlake(EvalState & state, const FlakeRef & originalRef, bool allowLookup
 }
 
 /* Compute an in-memory lock file for the specified top-level flake,
-   and optionally write it to file, it the flake is writable. */
+   and optionally write it to file, if the flake is writable. */
 LockedFlake lockFlake(
     EvalState & state,
     const FlakeRef & topRef,

src/libexpr/flake/flakeref.cc

@@ -16,10 +16,10 @@ const static std::string subDirRegex = subDirElemRegex + "(?:/" + subDirElemRege
 
 std::string FlakeRef::to_string() const
 {
-    auto url = input.toURL();
+    std::map<std::string, std::string> extraQuery;
     if (subdir != "")
-        url.query.insert_or_assign("dir", subdir);
+        extraQuery.insert_or_assign("dir", subdir);
-    return url.to_string();
+    return input.toURLString(extraQuery);
 }
 
 fetchers::Attrs FlakeRef::toAttrs() const
@@ -157,7 +157,8 @@ std::pair<FlakeRef, std::string> parseFlakeRefWithFragment(
         } else {
             if (!hasPrefix(path, "/"))
                 throw BadURL("flake reference '%s' is not an absolute path", url);
-            path = canonPath(path);
+            auto query = decodeQuery(match[2]);
+            path = canonPath(path + "/" + get(query, "dir").value_or(""));
         }
 
         fetchers::Attrs attrs;

src/libexpr/primops.cc

@@ -2236,6 +2236,10 @@ static RegisterPrimOp primop_catAttrs({
 static void prim_functionArgs(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     state.forceValue(*args[0], pos);
+    if (args[0]->type == tPrimOpApp || args[0]->type == tPrimOp) {
+        state.mkAttrs(v, 0);
+        return;
+    }
     if (args[0]->type != tLambda)
         throw TypeError({
             .hint = hintfmt("'functionArgs' requires a function"),

src/libfetchers/fetchers.cc

@@ -69,6 +69,14 @@ ParsedURL Input::toURL() const
     return scheme->toURL(*this);
 }
 
+std::string Input::toURLString(const std::map<std::string, std::string> & extraQuery) const
+{
+    auto url = toURL();
+    for (auto & attr : extraQuery)
+        url.query.insert(attr);
+    return url.to_string();
+}
+
 std::string Input::to_string() const
 {
     return toURL().to_string();

src/libfetchers/fetchers.hh

@@ -39,6 +39,8 @@ public:
 
     ParsedURL toURL() const;
 
+    std::string toURLString(const std::map<std::string, std::string> & extraQuery = {}) const;
+
     std::string to_string() const;
 
     Attrs toAttrs() const;
@@ -73,7 +75,7 @@ public:
 
     StorePath computeStorePath(Store & store) const;
 
-    // Convience functions for common attributes.
+    // Convenience functions for common attributes.
     std::string getType() const;
     std::optional<Hash> getNarHash() const;
     std::optional<std::string> getRef() const;
@@ -119,12 +121,14 @@ DownloadFileResult downloadFile(
     ref<Store> store,
     const std::string & url,
     const std::string & name,
-    bool immutable);
+    bool immutable,
+    const Headers & headers = {});
 
 std::pair<Tree, time_t> downloadTarball(
     ref<Store> store,
     const std::string & url,
     const std::string & name,
-    bool immutable);
+    bool immutable,
+    const Headers & headers = {});
 
 }

src/libfetchers/github.cc

@@ -3,12 +3,20 @@
 #include "fetchers.hh"
 #include "globals.hh"
 #include "store-api.hh"
+#include "types.hh"
 #include "url-parts.hh"
 
+#include <optional>
 #include <nlohmann/json.hpp>
 
 namespace nix::fetchers {
 
+struct DownloadUrl
+{
+    std::string url;
+    Headers headers;
+};
+
 // A github or gitlab host
 const static std::string hostRegexS = "[a-zA-Z0-9.]*"; // FIXME: check
 std::regex hostRegex(hostRegexS, std::regex::ECMAScript);
@@ -17,6 +25,8 @@ struct GitArchiveInputScheme : InputScheme
 {
     virtual std::string type() = 0;
 
+    virtual std::optional<std::pair<std::string, std::string> > accessHeaderFromToken(const std::string & token) const = 0;
+
     std::optional<Input> inputFromURL(const ParsedURL & url) override
     {
         if (url.scheme != type()) return {};
@@ -130,9 +140,31 @@ struct GitArchiveInputScheme : InputScheme
         return input;
     }
 
+    std::optional<std::string> getAccessToken(const std::string & host) const
+    {
+        auto tokens = settings.accessTokens.get();
+        if (auto token = get(tokens, host))
+            return *token;
+        return {};
+    }
+
+    Headers makeHeadersWithAuthTokens(const std::string & host) const
+    {
+        Headers headers;
+        auto accessToken = getAccessToken(host);
+        if (accessToken) {
+            auto hdr = accessHeaderFromToken(*accessToken);
+            if (hdr)
+                headers.push_back(*hdr);
+            else
+                warn("Unrecognized access token for host '%s'", host);
+        }
+        return headers;
+    }
+
     virtual Hash getRevFromRef(nix::ref<Store> store, const Input & input) const = 0;
 
-    virtual std::string getDownloadUrl(const Input & input) const = 0;
+    virtual DownloadUrl getDownloadUrl(const Input & input) const = 0;
 
     std::pair<Tree, Input> fetch(ref<Store> store, const Input & _input) override
     {
@@ -161,7 +193,7 @@ struct GitArchiveInputScheme : InputScheme
 
         auto url = getDownloadUrl(input);
 
-        auto [tree, lastModified] = downloadTarball(store, url, "source", true);
+        auto [tree, lastModified] = downloadTarball(store, url.url, "source", true, url.headers);
 
         input.attrs.insert_or_assign("lastModified", lastModified);
 
@@ -183,49 +215,52 @@ struct GitHubInputScheme : GitArchiveInputScheme
 {
     std::string type() override { return "github"; }
 
-    void addAccessToken(std::string & url) const
+    std::optional<std::pair<std::string, std::string> > accessHeaderFromToken(const std::string & token) const
     {
-        std::string accessToken = settings.githubAccessToken.get();
+        // Github supports PAT/OAuth2 tokens and HTTP Basic
-        if (accessToken != "")
+        // Authentication.  The former simply specifies the token, the
-            url += "?access_token=" + accessToken;
+        // latter can use the token as the password.  Only the first
+        // is used here. See
+        // https://developer.github.com/v3/#authentication and
+        // https://docs.github.com/en/developers/apps/authorizing-oath-apps
+        return std::pair<std::string, std::string>("Authorization", fmt("token %s", token));
     }
 
     Hash getRevFromRef(nix::ref<Store> store, const Input & input) const override
     {
-        auto host_url = maybeGetStrAttr(input.attrs, "url").value_or("github.com");
+        auto host = maybeGetStrAttr(input.attrs, "host").value_or("github.com");
         auto url = fmt("https://api.%s/repos/%s/%s/commits/%s", // FIXME: check
-            host_url, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"), *input.getRef());
+            host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"), *input.getRef());
 
-        addAccessToken(url);
+        Headers headers = makeHeadersWithAuthTokens(host);
 
         auto json = nlohmann::json::parse(
             readFile(
                 store->toRealPath(
-                    downloadFile(store, url, "source", false).storePath)));
+                    downloadFile(store, url, "source", false, headers).storePath)));
         auto rev = Hash::parseAny(std::string { json["sha"] }, htSHA1);
         debug("HEAD revision for '%s' is %s", url, rev.gitRev());
         return rev;
     }
 
-    std::string getDownloadUrl(const Input & input) const override
+    DownloadUrl getDownloadUrl(const Input & input) const override
     {
         // FIXME: use regular /archive URLs instead? api.github.com
         // might have stricter rate limits.
-        auto host_url = maybeGetStrAttr(input.attrs, "host").value_or("github.com");
+        auto host = maybeGetStrAttr(input.attrs, "host").value_or("github.com");
         auto url = fmt("https://api.%s/repos/%s/%s/tarball/%s", // FIXME: check if this is correct for self hosted instances
-            host_url, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
+            host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
             input.getRev()->to_string(Base16, false));
 
-        addAccessToken(url);
+        Headers headers = makeHeadersWithAuthTokens(host);
-
+        return DownloadUrl { url, headers };
-        return url;
     }
 
     void clone(const Input & input, const Path & destDir) override
     {
-        auto host_url = maybeGetStrAttr(input.attrs, "url").value_or("github.com");
+        auto host = maybeGetStrAttr(input.attrs, "host").value_or("github.com");
         Input::fromURL(fmt("git+ssh://git@%s/%s/%s.git",
-                host_url, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
+                host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
             .applyOverrides(input.getRef().value_or("HEAD"), input.getRev())
             .clone(destDir);
     }
@@ -235,42 +270,65 @@ struct GitLabInputScheme : GitArchiveInputScheme
 {
     std::string type() override { return "gitlab"; }
 
+    std::optional<std::pair<std::string, std::string> > accessHeaderFromToken(const std::string & token) const
+    {
+        // Gitlab supports 4 kinds of authorization, two of which are
+        // relevant here: OAuth2 and PAT (Private Access Token).  The
+        // user can indicate which token is used by specifying the
+        // token as <TYPE>:<VALUE>, where type is "OAuth2" or "PAT".
+        // If the <TYPE> is unrecognized, this will fall back to
+        // treating this simply has <HDRNAME>:<HDRVAL>.  See
+        // https://docs.gitlab.com/12.10/ee/api/README.html#authentication
+        auto fldsplit = token.find_first_of(':');
+        // n.b. C++20 would allow: if (token.starts_with("OAuth2:")) ...
+        if ("OAuth2" == token.substr(0, fldsplit))
+            return std::make_pair("Authorization", fmt("Bearer %s", token.substr(fldsplit+1)));
+        if ("PAT" == token.substr(0, fldsplit))
+            return std::make_pair("Private-token", token.substr(fldsplit+1));
+        warn("Unrecognized GitLab token type %s",  token.substr(0, fldsplit));
+        return std::nullopt;
+    }
+
     Hash getRevFromRef(nix::ref<Store> store, const Input & input) const override
     {
-        auto host_url = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
+        auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
+        // See rate limiting note below
         auto url = fmt("https://%s/api/v4/projects/%s%%2F%s/repository/commits?ref_name=%s",
-            host_url, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"), *input.getRef());
+            host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"), *input.getRef());
+
+        Headers headers = makeHeadersWithAuthTokens(host);
+
         auto json = nlohmann::json::parse(
             readFile(
                 store->toRealPath(
-                    downloadFile(store, url, "source", false).storePath)));
+                    downloadFile(store, url, "source", false, headers).storePath)));
         auto rev = Hash::parseAny(std::string(json[0]["id"]), htSHA1);
         debug("HEAD revision for '%s' is %s", url, rev.gitRev());
         return rev;
     }
 
-    std::string getDownloadUrl(const Input & input) const override
+    DownloadUrl getDownloadUrl(const Input & input) const override
     {
-        // FIXME: This endpoint has a rate limit threshold of 5 requests per minute
+        // This endpoint has a rate limit threshold that may be
-        auto host_url = maybeGetStrAttr(input.attrs, "url").value_or("gitlab.com");
+        // server-specific and vary based whether the user is
+        // authenticated via an accessToken or not, but the usual rate
+        // is 10 reqs/sec/ip-addr.  See
+        // https://docs.gitlab.com/ee/user/gitlab_com/index.html#gitlabcom-specific-rate-limits
+        auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
         auto url = fmt("https://%s/api/v4/projects/%s%%2F%s/repository/archive.tar.gz?sha=%s",
-            host_url, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
+            host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo"),
             input.getRev()->to_string(Base16, false));
 
-        /* # FIXME: add privat token auth (`curl --header "PRIVATE-TOKEN: <your_access_token>"`)
+        Headers headers = makeHeadersWithAuthTokens(host);
-        std::string accessToken = settings.githubAccessToken.get();
+        return DownloadUrl { url, headers };
-        if (accessToken != "")
-            url += "?access_token=" + accessToken;*/
-
-        return url;
     }
 
     void clone(const Input & input, const Path & destDir) override
     {
-        auto host_url = maybeGetStrAttr(input.attrs, "url").value_or("gitlab.com");
+        auto host = maybeGetStrAttr(input.attrs, "host").value_or("gitlab.com");
         // FIXME: get username somewhere
         Input::fromURL(fmt("git+ssh://git@%s/%s/%s.git",
-                host_url, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
+                host, getStrAttr(input.attrs, "owner"), getStrAttr(input.attrs, "repo")))
             .applyOverrides(input.getRef().value_or("HEAD"), input.getRev())
             .clone(destDir);
     }

src/libfetchers/tarball.cc

@@ -5,6 +5,7 @@
 #include "store-api.hh"
 #include "archive.hh"
 #include "tarfile.hh"
+#include "types.hh"
 
 namespace nix::fetchers {
 
@@ -12,7 +13,8 @@ DownloadFileResult downloadFile(
     ref<Store> store,
     const std::string & url,
     const std::string & name,
-    bool immutable)
+    bool immutable,
+    const Headers & headers)
 {
     // FIXME: check store
 
@@ -37,6 +39,7 @@ DownloadFileResult downloadFile(
         return useCached();
 
     FileTransferRequest request(url);
+    request.headers = headers;
     if (cached)
         request.expectedETag = getStrAttr(cached->infoAttrs, "etag");
     FileTransferResult res;
@@ -111,7 +114,8 @@ std::pair<Tree, time_t> downloadTarball(
     ref<Store> store,
     const std::string & url,
     const std::string & name,
-    bool immutable)
+    bool immutable,
+    const Headers & headers)
 {
     Attrs inAttrs({
         {"type", "tarball"},
@@ -127,7 +131,7 @@ std::pair<Tree, time_t> downloadTarball(
             getIntAttr(cached->infoAttrs, "lastModified")
         };
 
-    auto res = downloadFile(store, url, name, immutable);
+    auto res = downloadFile(store, url, name, immutable, headers);
 
     std::optional<StorePath> unpackedStorePath;
     time_t lastModified;

src/libmain/progress-bar.cc

@@ -256,7 +256,7 @@ public:
         }
 
         else if (type == resBuildLogLine || type == resPostBuildLogLine) {
-            auto lastLine = trim(getS(fields, 0));
+            auto lastLine = chomp(getS(fields, 0));
             if (!lastLine.empty()) {
                 auto i = state->its.find(act);
                 assert(i != state->its.end());

src/libstore/binary-cache-store.cc

@@ -142,17 +142,10 @@ struct FileSource : FdSource
     }
 };
 
-void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource,
+ref<const ValidPathInfo> BinaryCacheStore::addToStoreCommon(
-    RepairFlag repair, CheckSigsFlag checkSigs)
+    Source & narSource, RepairFlag repair, CheckSigsFlag checkSigs,
+    std::function<ValidPathInfo(HashResult)> mkInfo)
 {
-    assert(info.narSize);
-
-    if (!repair && isValidPath(info.path)) {
-        // FIXME: copyNAR -> null sink
-        narSource.drain();
-        return;
-    }
-
     auto [fdTemp, fnTemp] = createTempFile();
 
     AutoDelete autoDelete(fnTemp);
@@ -162,13 +155,15 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
     /* Read the NAR simultaneously into a CompressionSink+FileSink (to
        write the compressed NAR to disk), into a HashSink (to get the
        NAR hash), and into a NarAccessor (to get the NAR listing). */
-    HashSink fileHashSink(htSHA256);
+    HashSink fileHashSink { htSHA256 };
     std::shared_ptr<FSAccessor> narAccessor;
+    HashSink narHashSink { htSHA256 };
     {
     FdSink fileSink(fdTemp.get());
-    TeeSink teeSink(fileSink, fileHashSink);
+    TeeSink teeSinkCompressed { fileSink, fileHashSink };
-    auto compressionSink = makeCompressionSink(compression, teeSink);
+    auto compressionSink = makeCompressionSink(compression, teeSinkCompressed);
-    TeeSource teeSource(narSource, *compressionSink);
+    TeeSink teeSinkUncompressed { *compressionSink, narHashSink };
+    TeeSource teeSource { narSource, teeSinkUncompressed };
     narAccessor = makeNarAccessor(teeSource);
     compressionSink->finish();
     fileSink.flush();
@@ -176,9 +171,8 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
 
     auto now2 = std::chrono::steady_clock::now();
 
+    auto info = mkInfo(narHashSink.finish());
     auto narInfo = make_ref<NarInfo>(info);
-    narInfo->narSize = info.narSize;
-    narInfo->narHash = info.narHash;
     narInfo->compression = compression;
     auto [fileHash, fileSize] = fileHashSink.finish();
     narInfo->fileHash = fileHash;
@@ -299,6 +293,41 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
     writeNarInfo(narInfo);
 
     stats.narInfoWrite++;
+
+    return narInfo;
+}
+
+void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource,
+    RepairFlag repair, CheckSigsFlag checkSigs)
+{
+    if (!repair && isValidPath(info.path)) {
+        // FIXME: copyNAR -> null sink
+        narSource.drain();
+        return;
+    }
+
+    addToStoreCommon(narSource, repair, checkSigs, {[&](HashResult nar) {
+        /* FIXME reinstate these, once we can correctly do hash modulo sink as
+           needed. We need to throw here in case we uploaded a corrupted store path. */
+        // assert(info.narHash == nar.first);
+        // assert(info.narSize == nar.second);
+        return info;
+    }});
+}
+
+StorePath BinaryCacheStore::addToStoreFromDump(Source & dump, const string & name,
+    FileIngestionMethod method, HashType hashAlgo, RepairFlag repair)
+{
+    if (method != FileIngestionMethod::Recursive || hashAlgo != htSHA256)
+        unsupported("addToStoreFromDump");
+    return addToStoreCommon(dump, repair, CheckSigs, [&](HashResult nar) {
+        ValidPathInfo info {
+            makeFixedOutputPath(method, nar.first, name),
+            nar.first,
+        };
+        info.narSize = nar.second;
+        return info;
+    })->path;
 }
 
 bool BinaryCacheStore::isValidPathUncached(const StorePath & storePath)
@@ -366,50 +395,52 @@ void BinaryCacheStore::queryPathInfoUncached(const StorePath & storePath,
 StorePath BinaryCacheStore::addToStore(const string & name, const Path & srcPath,
     FileIngestionMethod method, HashType hashAlgo, PathFilter & filter, RepairFlag repair)
 {
-    // FIXME: some cut&paste from LocalStore::addToStore().
+    /* FIXME: Make BinaryCacheStore::addToStoreCommon support
+       non-recursive+sha256 so we can just use the default
+       implementation of this method in terms of addToStoreFromDump. */
 
-    /* Read the whole path into memory. This is not a very scalable
+    HashSink sink { hashAlgo };
-       method for very large paths, but `copyPath' is mainly used for
-       small files. */
-    StringSink sink;
-    std::optional<Hash> h;
     if (method == FileIngestionMethod::Recursive) {
         dumpPath(srcPath, sink, filter);
-        h = hashString(hashAlgo, *sink.s);
     } else {
-        auto s = readFile(srcPath);
+        readFile(srcPath, sink);
-        dumpString(s, sink);
-        h = hashString(hashAlgo, s);
     }
+    auto h = sink.finish().first;
 
-    ValidPathInfo info {
+    auto source = sinkToSource([&](Sink & sink) {
-        makeFixedOutputPath(method, *h, name),
+        dumpPath(srcPath, sink, filter);
-        Hash::dummy, // Will be fixed in addToStore, which recomputes nar hash
+    });
-    };
+    return addToStoreCommon(*source, repair, CheckSigs, [&](HashResult nar) {
-
+        ValidPathInfo info {
-    auto source = StringSource { *sink.s };
+            makeFixedOutputPath(method, h, name),
-    addToStore(info, source, repair, CheckSigs);
+            nar.first,
-
+        };
-    return std::move(info.path);
+        info.narSize = nar.second;
+        info.ca = FixedOutputHash {
+            .method = method,
+            .hash = h,
+        };
+        return info;
+    })->path;
 }
 
 StorePath BinaryCacheStore::addTextToStore(const string & name, const string & s,
     const StorePathSet & references, RepairFlag repair)
 {
-    ValidPathInfo info {
+    auto textHash = hashString(htSHA256, s);
-        computeStorePathForText(name, s, references),
+    auto path = makeTextPath(name, textHash, references);
-        Hash::dummy, // Will be fixed in addToStore, which recomputes nar hash
-    };
-    info.references = references;
 
-    if (repair || !isValidPath(info.path)) {
+    if (!repair && isValidPath(path))
-        StringSink sink;
+        return path;
-        dumpString(s, sink);
-        auto source = StringSource { *sink.s };
-        addToStore(info, source, repair, CheckSigs);
-    }
 
-    return std::move(info.path);
+    auto source = StringSource { s };
+    return addToStoreCommon(source, repair, CheckSigs, [&](HashResult nar) {
+        ValidPathInfo info { path, nar.first };
+        info.narSize = nar.second;
+        info.ca = TextHash { textHash };
+        info.references = references;
+        return info;
+    })->path;
 }
 
 ref<FSAccessor> BinaryCacheStore::getFSAccessor()

src/libstore/binary-cache-store.hh

@@ -72,6 +72,10 @@ private:
 
     void writeNarInfo(ref<NarInfo> narInfo);
 
+    ref<const ValidPathInfo> addToStoreCommon(
+        Source & narSource, RepairFlag repair, CheckSigsFlag checkSigs,
+        std::function<ValidPathInfo(HashResult)> mkInfo);
+
 public:
 
     bool isValidPathUncached(const StorePath & path) override;
@@ -85,6 +89,9 @@ public:
     void addToStore(const ValidPathInfo & info, Source & narSource,
         RepairFlag repair, CheckSigsFlag checkSigs) override;
 
+    StorePath addToStoreFromDump(Source & dump, const string & name,
+        FileIngestionMethod method, HashType hashAlgo, RepairFlag repair) override;
+
     StorePath addToStore(const string & name, const Path & srcPath,
         FileIngestionMethod method, HashType hashAlgo,
         PathFilter & filter, RepairFlag repair) override;

src/libstore/build.cc

@@ -296,9 +296,21 @@ public:
     ~Worker();
 
     /* Make a goal (with caching). */
-    GoalPtr makeDerivationGoal(const StorePath & drvPath, const StringSet & wantedOutputs, BuildMode buildMode = bmNormal);
+
-    std::shared_ptr<DerivationGoal> makeBasicDerivationGoal(const StorePath & drvPath,
+    /* derivation goal */
-        const BasicDerivation & drv, BuildMode buildMode = bmNormal);
+private:
+    std::shared_ptr<DerivationGoal> makeDerivationGoalCommon(
+        const StorePath & drvPath, const StringSet & wantedOutputs,
+        std::function<std::shared_ptr<DerivationGoal>()> mkDrvGoal);
+public:
+    std::shared_ptr<DerivationGoal> makeDerivationGoal(
+        const StorePath & drvPath,
+        const StringSet & wantedOutputs, BuildMode buildMode = bmNormal);
+    std::shared_ptr<DerivationGoal> makeBasicDerivationGoal(
+        const StorePath & drvPath, const BasicDerivation & drv,
+        const StringSet & wantedOutputs, BuildMode buildMode = bmNormal);
+
+    /* substitution goal */
     GoalPtr makeSubstitutionGoal(const StorePath & storePath, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
 
     /* Remove a dead goal. */
@@ -949,10 +961,12 @@ private:
     friend struct RestrictedStore;
 
 public:
-    DerivationGoal(const StorePath & drvPath, const StringSet & wantedOutputs,
+    DerivationGoal(const StorePath & drvPath,
-        Worker & worker, BuildMode buildMode = bmNormal);
+        const StringSet & wantedOutputs, Worker & worker,
+        BuildMode buildMode = bmNormal);
     DerivationGoal(const StorePath & drvPath, const BasicDerivation & drv,
-        Worker & worker, BuildMode buildMode = bmNormal);
+        const StringSet & wantedOutputs, Worker & worker,
+        BuildMode buildMode = bmNormal);
     ~DerivationGoal();
 
     /* Whether we need to perform hash rewriting if there are valid output paths. */
@@ -994,6 +1008,8 @@ private:
     void tryLocalBuild();
     void buildDone();
 
+    void resolvedFinished();
+
     /* Is the build hook willing to perform the build? */
     HookReply tryBuildHook();
 
@@ -1085,8 +1101,8 @@ private:
 const Path DerivationGoal::homeDir = "/homeless-shelter";
 
 
-DerivationGoal::DerivationGoal(const StorePath & drvPath, const StringSet & wantedOutputs,
+DerivationGoal::DerivationGoal(const StorePath & drvPath,
-    Worker & worker, BuildMode buildMode)
+    const StringSet & wantedOutputs, Worker & worker, BuildMode buildMode)
     : Goal(worker)
     , useDerivation(true)
     , drvPath(drvPath)
@@ -1094,7 +1110,9 @@ DerivationGoal::DerivationGoal(const StorePath & drvPath, const StringSet & want
     , buildMode(buildMode)
 {
     state = &DerivationGoal::getDerivation;
-    name = fmt("building of '%s'", worker.store.printStorePath(this->drvPath));
+    name = fmt(
+        "building of '%s' from .drv file",
+        StorePathWithOutputs { drvPath, wantedOutputs }.to_string(worker.store));
     trace("created");
 
     mcExpectedBuilds = std::make_unique<MaintainCount<uint64_t>>(worker.expectedBuilds);
@@ -1103,15 +1121,18 @@ DerivationGoal::DerivationGoal(const StorePath & drvPath, const StringSet & want
 
 
 DerivationGoal::DerivationGoal(const StorePath & drvPath, const BasicDerivation & drv,
-    Worker & worker, BuildMode buildMode)
+    const StringSet & wantedOutputs, Worker & worker, BuildMode buildMode)
     : Goal(worker)
     , useDerivation(false)
     , drvPath(drvPath)
+    , wantedOutputs(wantedOutputs)
     , buildMode(buildMode)
 {
     this->drv = std::make_unique<BasicDerivation>(BasicDerivation(drv));
     state = &DerivationGoal::haveDerivation;
-    name = fmt("building of %s", StorePathWithOutputs { drvPath, drv.outputNames() }.to_string(worker.store));
+    name = fmt(
+        "building of '%s' from in-memory derivation",
+        StorePathWithOutputs { drvPath, drv.outputNames() }.to_string(worker.store));
     trace("created");
 
     mcExpectedBuilds = std::make_unique<MaintainCount<uint64_t>>(worker.expectedBuilds);
@@ -1464,8 +1485,40 @@ void DerivationGoal::inputsRealised()
     /* Determine the full set of input paths. */
 
     /* First, the input derivations. */
-    if (useDerivation)
+    if (useDerivation) {
-        for (auto & [depDrvPath, wantedDepOutputs] : dynamic_cast<Derivation *>(drv.get())->inputDrvs) {
+        auto & fullDrv = *dynamic_cast<Derivation *>(drv.get());
+
+        if (!fullDrv.inputDrvs.empty() && fullDrv.type() == DerivationType::CAFloating) {
+            /* We are be able to resolve this derivation based on the
+               now-known results of dependencies. If so, we become a stub goal
+               aliasing that resolved derivation goal */
+            std::optional attempt = fullDrv.tryResolve(worker.store);
+            assert(attempt);
+            Derivation drvResolved { *std::move(attempt) };
+
+            auto pathResolved = writeDerivation(worker.store, drvResolved);
+            /* Add to memotable to speed up downstream goal's queries with the
+               original derivation. */
+            drvPathResolutions.lock()->insert_or_assign(drvPath, pathResolved);
+
+            auto msg = fmt("Resolved derivation: '%s' -> '%s'",
+                worker.store.printStorePath(drvPath),
+                worker.store.printStorePath(pathResolved));
+            act = std::make_unique<Activity>(*logger, lvlInfo, actBuildWaiting, msg,
+                Logger::Fields {
+                       worker.store.printStorePath(drvPath),
+                       worker.store.printStorePath(pathResolved),
+                   });
+
+            auto resolvedGoal = worker.makeDerivationGoal(
+                pathResolved, wantedOutputs, buildMode);
+            addWaitee(resolvedGoal);
+
+            state = &DerivationGoal::resolvedFinished;
+            return;
+        }
+
+        for (auto & [depDrvPath, wantedDepOutputs] : fullDrv.inputDrvs) {
             /* Add the relevant output closures of the input derivation
                `i' as input paths.  Only add the closures of output paths
                that are specified as inputs. */
@@ -1485,6 +1538,7 @@ void DerivationGoal::inputsRealised()
                         worker.store.printStorePath(drvPath), j, worker.store.printStorePath(drvPath));
             }
         }
+    }
 
     /* Second, the input sources. */
     worker.store.computeFSClosure(drv->inputSrcs, inputPaths);
@@ -1612,6 +1666,13 @@ void DerivationGoal::tryToBuild()
 
     actLock.reset();
 
+    state = &DerivationGoal::tryLocalBuild;
+    worker.wakeUp(shared_from_this());
+}
+
+void DerivationGoal::tryLocalBuild() {
+    bool buildLocally = buildMode != bmNormal || parsedDrv->willBuildLocally(worker.store);
+
     /* Make sure that we are allowed to start a build.  If this
        derivation prefers to be done locally, do it even if
        maxBuildJobs is 0. */
@@ -1622,12 +1683,6 @@ void DerivationGoal::tryToBuild()
         return;
     }
 
-    state = &DerivationGoal::tryLocalBuild;
-    worker.wakeUp(shared_from_this());
-}
-
-void DerivationGoal::tryLocalBuild() {
-
     /* If `build-users-group' is not empty, then we have to build as
        one of the members of that group. */
     if (settings.buildUsersGroup != "" && getuid() == 0) {
@@ -1942,6 +1997,9 @@ void DerivationGoal::buildDone()
     done(BuildResult::Built);
 }
 
+void DerivationGoal::resolvedFinished() {
+    done(BuildResult::Built);
+}
 
 HookReply DerivationGoal::tryBuildHook()
 {
@@ -2012,7 +2070,7 @@ HookReply DerivationGoal::tryBuildHook()
 
     /* Tell the hook all the inputs that have to be copied to the
        remote system. */
-    writeStorePaths(worker.store, hook->sink, inputPaths);
+    worker_proto::write(worker.store, hook->sink, inputPaths);
 
     /* Tell the hooks the missing outputs that have to be copied back
        from the remote system. */
@@ -2023,7 +2081,7 @@ HookReply DerivationGoal::tryBuildHook()
             if (buildMode != bmCheck && status.known->isValid()) continue;
             missingPaths.insert(status.known->path);
         }
-        writeStorePaths(worker.store, hook->sink, missingPaths);
+        worker_proto::write(worker.store, hook->sink, missingPaths);
     }
 
     hook->sink = FdSink();
@@ -4231,11 +4289,13 @@ void DerivationGoal::registerOutputs()
     /* Register each output path as valid, and register the sets of
        paths referenced by each of them.  If there are cycles in the
        outputs, this will fail. */
-    ValidPathInfos infos2;
+    {
-    for (auto & [outputName, newInfo] : infos) {
+        ValidPathInfos infos2;
-        infos2.push_back(newInfo);
+        for (auto & [outputName, newInfo] : infos) {
+            infos2.push_back(newInfo);
+        }
+        worker.store.registerValidPaths(infos2);
     }
-    worker.store.registerValidPaths(infos2);
 
     /* In case of a fixed-output derivation hash mismatch, throw an
        exception now that we have registered the output as valid. */
@@ -4247,12 +4307,21 @@ void DerivationGoal::registerOutputs()
        means it's safe to link the derivation to the output hash. We must do
        that for floating CA derivations, which otherwise couldn't be cached,
        but it's fine to do in all cases. */
-    for (auto & [outputName, newInfo] : infos) {
+    bool isCaFloating = drv->type() == DerivationType::CAFloating;
-        /* FIXME: we will want to track this mapping in the DB whether or
+
-           not we have a drv file. */
+    auto drvPathResolved = drvPath;
-        if (useDerivation)
+    if (!useDerivation && isCaFloating) {
-            worker.store.linkDeriverToPath(drvPath, outputName, newInfo.path);
+        /* Once a floating CA derivations reaches this point, it
+           must already be resolved, so we don't bother trying to
+           downcast drv to get would would just be an empty
+           inputDrvs field. */
+        Derivation drv2 { *drv };
+        drvPathResolved = writeDerivation(worker.store, drv2);
     }
+
+    if (useDerivation || isCaFloating)
+        for (auto & [outputName, newInfo] : infos)
+            worker.store.linkDeriverToPath(drvPathResolved, outputName, newInfo.path);
 }
 
 
@@ -4542,7 +4611,7 @@ void DerivationGoal::flushLine()
 
 std::map<std::string, std::optional<StorePath>> DerivationGoal::queryPartialDerivationOutputMap()
 {
-    if (drv->type() != DerivationType::CAFloating) {
+    if (!useDerivation || drv->type() != DerivationType::CAFloating) {
         std::map<std::string, std::optional<StorePath>> res;
         for (auto & [name, output] : drv->outputs)
             res.insert_or_assign(name, output.path(worker.store, drv->name, name));
@@ -4554,7 +4623,7 @@ std::map<std::string, std::optional<StorePath>> DerivationGoal::queryPartialDeri
 
 OutputPathMap DerivationGoal::queryDerivationOutputMap()
 {
-    if (drv->type() != DerivationType::CAFloating) {
+    if (!useDerivation || drv->type() != DerivationType::CAFloating) {
         OutputPathMap res;
         for (auto & [name, output] : drv->outputsAndOptPaths(worker.store))
             res.insert_or_assign(name, *output.second);
@@ -5031,35 +5100,52 @@ Worker::~Worker()
 }
 
 
-GoalPtr Worker::makeDerivationGoal(const StorePath & path,
+std::shared_ptr<DerivationGoal> Worker::makeDerivationGoalCommon(
-    const StringSet & wantedOutputs, BuildMode buildMode)
+    const StorePath & drvPath,
+    const StringSet & wantedOutputs,
+    std::function<std::shared_ptr<DerivationGoal>()> mkDrvGoal)
 {
-    GoalPtr goal = derivationGoals[path].lock(); // FIXME
+    WeakGoalPtr & abstract_goal_weak = derivationGoals[drvPath];
-    if (!goal) {
+    GoalPtr abstract_goal = abstract_goal_weak.lock(); // FIXME
-        goal = std::make_shared<DerivationGoal>(path, wantedOutputs, *this, buildMode);
+    std::shared_ptr<DerivationGoal> goal;
-        derivationGoals.insert_or_assign(path, goal);
+    if (!abstract_goal) {
+        goal = mkDrvGoal();
+        abstract_goal_weak = goal;
         wakeUp(goal);
-    } else
+    } else {
-        (dynamic_cast<DerivationGoal *>(goal.get()))->addWantedOutputs(wantedOutputs);
+        goal = std::dynamic_pointer_cast<DerivationGoal>(abstract_goal);
+        assert(goal);
+        goal->addWantedOutputs(wantedOutputs);
+    }
     return goal;
 }
 
 
-std::shared_ptr<DerivationGoal> Worker::makeBasicDerivationGoal(const StorePath & drvPath,
+std::shared_ptr<DerivationGoal> Worker::makeDerivationGoal(const StorePath & drvPath,
-    const BasicDerivation & drv, BuildMode buildMode)
+    const StringSet & wantedOutputs, BuildMode buildMode)
 {
-    auto goal = std::make_shared<DerivationGoal>(drvPath, drv, *this, buildMode);
+    return makeDerivationGoalCommon(drvPath, wantedOutputs, [&]() {
-    wakeUp(goal);
+        return std::make_shared<DerivationGoal>(drvPath, wantedOutputs, *this, buildMode);
-    return goal;
+    });
+}
+
+
+std::shared_ptr<DerivationGoal> Worker::makeBasicDerivationGoal(const StorePath & drvPath,
+    const BasicDerivation & drv, const StringSet & wantedOutputs, BuildMode buildMode)
+{
+    return makeDerivationGoalCommon(drvPath, wantedOutputs, [&]() {
+        return std::make_shared<DerivationGoal>(drvPath, drv, wantedOutputs, *this, buildMode);
+    });
 }
 
 
 GoalPtr Worker::makeSubstitutionGoal(const StorePath & path, RepairFlag repair, std::optional<ContentAddress> ca)
 {
-    GoalPtr goal = substitutionGoals[path].lock(); // FIXME
+    WeakGoalPtr & goal_weak = substitutionGoals[path];
+    GoalPtr goal = goal_weak.lock(); // FIXME
     if (!goal) {
         goal = std::make_shared<SubstitutionGoal>(path, *this, repair, ca);
-        substitutionGoals.insert_or_assign(path, goal);
+        goal_weak = goal;
         wakeUp(goal);
     }
     return goal;
@@ -5490,7 +5576,7 @@ BuildResult LocalStore::buildDerivation(const StorePath & drvPath, const BasicDe
     BuildMode buildMode)
 {
     Worker worker(*this);
-    auto goal = worker.makeBasicDerivationGoal(drvPath, drv, buildMode);
+    auto goal = worker.makeBasicDerivationGoal(drvPath, drv, {}, buildMode);
 
     BuildResult result;
 

src/libstore/daemon.cc

@@ -247,7 +247,7 @@ static void writeValidPathInfo(
 {
     to << (info->deriver ? store->printStorePath(*info->deriver) : "")
        << info->narHash.to_string(Base16, false);
-    writeStorePaths(*store, to, info->referencesPossiblyToSelf());
+    worker_proto::write(*store, to, info->referencesPossiblyToSelf());
     to << info->registrationTime << info->narSize;
     if (GET_PROTOCOL_MINOR(clientVersion) >= 16) {
         to << info->ultimate
@@ -272,11 +272,11 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     }
 
     case wopQueryValidPaths: {
-        auto paths = readStorePaths<StorePathSet>(*store, from);
+        auto paths = worker_proto::read(*store, from, Phantom<StorePathSet> {});
         logger->startWork();
         auto res = store->queryValidPaths(paths);
         logger->stopWork();
-        writeStorePaths(*store, to, res);
+        worker_proto::write(*store, to, res);
         break;
     }
 
@@ -292,11 +292,11 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     }
 
     case wopQuerySubstitutablePaths: {
-        auto paths = readStorePaths<StorePathSet>(*store, from);
+        auto paths = worker_proto::read(*store, from, Phantom<StorePathSet> {});
         logger->startWork();
         auto res = store->querySubstitutablePaths(paths);
         logger->stopWork();
-        writeStorePaths(*store, to, res);
+        worker_proto::write(*store, to, res);
         break;
     }
 
@@ -325,7 +325,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
             paths = store->queryValidDerivers(path);
         else paths = store->queryDerivationOutputs(path);
         logger->stopWork();
-        writeStorePaths(*store, to, paths);
+        worker_proto::write(*store, to, paths);
         break;
     }
 
@@ -369,7 +369,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         if (GET_PROTOCOL_MINOR(clientVersion) >= 25) {
             auto name = readString(from);
             auto camStr = readString(from);
-            auto refs = readStorePaths<StorePathSet>(*store, from);
+            auto refs = worker_proto::read(*store, from, Phantom<StorePathSet> {});
             bool repairBool;
             from >> repairBool;
             auto repair = RepairFlag{repairBool};
@@ -449,7 +449,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     case wopAddTextToStore: {
         string suffix = readString(from);
         string s = readString(from);
-        auto refs = readStorePaths<StorePathSet>(*store, from);
+        auto refs = worker_proto::read(*store, from, Phantom<StorePathSet> {});
         logger->startWork();
         auto path = store->addTextToStore(suffix, s, refs, NoRepair);
         logger->stopWork();
@@ -546,6 +546,20 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
            are in fact content-addressed if we don't trust them. */
         assert(derivationIsCA(drv.type()) || trusted);
 
+        /* Recompute the derivation path when we cannot trust the original. */
+        if (!trusted) {
+            /* Recomputing the derivation path for input-address derivations
+               makes it harder to audit them after the fact, since we need the
+               original not-necessarily-resolved derivation to verify the drv
+               derivation as adequate claim to the input-addressed output
+               paths. */
+            assert(derivationIsCA(drv.type()));
+
+            Derivation drv2;
+            static_cast<BasicDerivation &>(drv2) = drv;
+            drvPath = writeDerivation(*store, Derivation { drv2 });
+        }
+
         auto res = store->buildDerivation(drvPath, drv, buildMode);
         logger->stopWork();
         to << res.status << res.errorMsg;
@@ -608,7 +622,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     case wopCollectGarbage: {
         GCOptions options;
         options.action = (GCOptions::GCAction) readInt(from);
-        options.pathsToDelete = readStorePaths<StorePathSet>(*store, from);
+        options.pathsToDelete = worker_proto::read(*store, from, Phantom<StorePathSet> {});
         from >> options.ignoreLiveness >> options.maxFreed;
         // obsolete fields
         readInt(from);
@@ -677,7 +691,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         else {
             to << 1
                << (i->second.deriver ? store->printStorePath(*i->second.deriver) : "");
-            writeStorePaths(*store, to, i->second.referencesPossiblyToSelf(path));
+            worker_proto::write(*store, to, i->second.referencesPossiblyToSelf(path));
             to << i->second.downloadSize
                << i->second.narSize;
         }
@@ -688,11 +702,11 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         SubstitutablePathInfos infos;
         StorePathCAMap pathsMap = {};
         if (GET_PROTOCOL_MINOR(clientVersion) < 22) {
-            auto paths = readStorePaths<StorePathSet>(*store, from);
+            auto paths = worker_proto::read(*store, from, Phantom<StorePathSet> {});
             for (auto & path : paths)
                 pathsMap.emplace(path, std::nullopt);
         } else
-            pathsMap = readStorePathCAMap(*store, from);
+            pathsMap = worker_proto::read(*store, from, Phantom<StorePathCAMap> {});
         logger->startWork();
         store->querySubstitutablePathInfos(pathsMap, infos);
         logger->stopWork();
@@ -700,7 +714,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         for (auto & i : infos) {
             to << store->printStorePath(i.first)
                << (i.second.deriver ? store->printStorePath(*i.second.deriver) : "");
-            writeStorePaths(*store, to, i.second.referencesPossiblyToSelf(i.first));
+            worker_proto::write(*store, to, i.second.referencesPossiblyToSelf(i.first));
             to << i.second.downloadSize << i.second.narSize;
         }
         break;
@@ -710,7 +724,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         logger->startWork();
         auto paths = store->queryAllValidPaths();
         logger->stopWork();
-        writeStorePaths(*store, to, paths);
+        worker_proto::write(*store, to, paths);
         break;
     }
 
@@ -782,7 +796,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         ValidPathInfo info { path, narHash };
         if (deriver != "")
             info.deriver = store->parseStorePath(deriver);
-        info.setReferencesPossiblyToSelf(readStorePaths<StorePathSet>(*store, from));
+        info.setReferencesPossiblyToSelf(worker_proto::read(*store, from, Phantom<StorePathSet> {}));
         from >> info.registrationTime >> info.narSize >> info.ultimate;
         info.sigs = readStrings<StringSet>(from);
         info.ca = parseContentAddressOpt(readString(from));
@@ -835,9 +849,9 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         uint64_t downloadSize, narSize;
         store->queryMissing(targets, willBuild, willSubstitute, unknown, downloadSize, narSize);
         logger->stopWork();
-        writeStorePaths(*store, to, willBuild);
+        worker_proto::write(*store, to, willBuild);
-        writeStorePaths(*store, to, willSubstitute);
+        worker_proto::write(*store, to, willSubstitute);
-        writeStorePaths(*store, to, unknown);
+        worker_proto::write(*store, to, unknown);
         to << downloadSize << narSize;
         break;
     }

src/libstore/derivations.cc

@@ -69,7 +69,7 @@ bool BasicDerivation::isBuiltin() const
 
 
 StorePath writeDerivation(Store & store,
-    const Derivation & drv, RepairFlag repair)
+    const Derivation & drv, RepairFlag repair, bool readOnly)
 {
     auto references = drv.inputSrcs;
     for (auto & i : drv.inputDrvs)
@@ -79,7 +79,7 @@ StorePath writeDerivation(Store & store,
        held during a garbage collection). */
     auto suffix = std::string(drv.name) + drvExtension;
     auto contents = drv.unparse(store, false);
-    return settings.readOnlyMode
+    return readOnly || settings.readOnlyMode
         ? store.computeStorePathForText(suffix, contents, references)
         : store.addTextToStore(suffix, contents, references, repair);
 }
@@ -584,7 +584,7 @@ Source & readDerivation(Source & in, const Store & store, BasicDerivation & drv,
         drv.outputs.emplace(std::move(name), std::move(output));
     }
 
-    drv.inputSrcs = readStorePaths<StorePathSet>(store, in);
+    drv.inputSrcs = worker_proto::read(store, in, Phantom<StorePathSet> {});
     in >> drv.platform >> drv.builder;
     drv.args = readStrings<Strings>(in);
 
@@ -622,7 +622,7 @@ void writeDerivation(Sink & out, const Store & store, const BasicDerivation & dr
             },
         }, i.second.output);
     }
-    writeStorePaths(store, out, drv.inputSrcs);
+    worker_proto::write(store, out, drv.inputSrcs);
     out << drv.platform << drv.builder << drv.args;
     out << drv.env.size();
     for (auto & i : drv.env)
@@ -644,4 +644,57 @@ std::string downstreamPlaceholder(const Store & store, const StorePath & drvPath
     return "/" + hashString(htSHA256, clearText).to_string(Base32, false);
 }
 
+
+// N.B. Outputs are left unchanged
+static void rewriteDerivation(Store & store, BasicDerivation & drv, const StringMap & rewrites) {
+
+    debug("Rewriting the derivation");
+
+    for (auto &rewrite: rewrites) {
+        debug("rewriting %s as %s", rewrite.first, rewrite.second);
+    }
+
+    drv.builder = rewriteStrings(drv.builder, rewrites);
+    for (auto & arg: drv.args) {
+        arg = rewriteStrings(arg, rewrites);
+    }
+
+    StringPairs newEnv;
+    for (auto & envVar: drv.env) {
+        auto envName = rewriteStrings(envVar.first, rewrites);
+        auto envValue = rewriteStrings(envVar.second, rewrites);
+        newEnv.emplace(envName, envValue);
+    }
+    drv.env = newEnv;
+}
+
+
+Sync<DrvPathResolutions> drvPathResolutions;
+
+std::optional<BasicDerivation> Derivation::tryResolve(Store & store) {
+    BasicDerivation resolved { *this };
+
+    // Input paths that we'll want to rewrite in the derivation
+    StringMap inputRewrites;
+
+    for (auto & input : inputDrvs) {
+        auto inputDrvOutputs = store.queryPartialDerivationOutputMap(input.first);
+        StringSet newOutputNames;
+        for (auto & outputName : input.second) {
+            auto actualPathOpt = inputDrvOutputs.at(outputName);
+            if (!actualPathOpt)
+                return std::nullopt;
+            auto actualPath = *actualPathOpt;
+            inputRewrites.emplace(
+                downstreamPlaceholder(store, input.first, outputName),
+                store.printStorePath(actualPath));
+            resolved.inputSrcs.insert(std::move(actualPath));
+        }
+    }
+
+    rewriteDerivation(store, resolved, inputRewrites);
+
+    return resolved;
+}
+
 }

src/libstore/derivations.hh

@@ -4,6 +4,7 @@
 #include "types.hh"
 #include "hash.hh"
 #include "content-address.hh"
+#include "sync.hh"
 
 #include <map>
 #include <variant>
@@ -100,7 +101,7 @@ struct BasicDerivation
     StringPairs env;
     std::string name;
 
-    BasicDerivation() { }
+    BasicDerivation() = default;
     virtual ~BasicDerivation() { };
 
     bool isBuiltin() const;
@@ -127,7 +128,17 @@ struct Derivation : BasicDerivation
     std::string unparse(const Store & store, bool maskOutputs,
         std::map<std::string, StringSet> * actualInputs = nullptr) const;
 
-    Derivation() { }
+    /* Return the underlying basic derivation but with these changes:
+
+	   1. Input drvs are emptied, but the outputs of them that were used are
+	      added directly to input sources.
+
+       2. Input placeholders are replaced with realized input store paths. */
+    std::optional<BasicDerivation> tryResolve(Store & store);
+
+    Derivation() = default;
+    Derivation(const BasicDerivation & bd) : BasicDerivation(bd) { }
+    Derivation(BasicDerivation && bd) : BasicDerivation(std::move(bd)) { }
 };
 
 
@@ -137,7 +148,9 @@ enum RepairFlag : bool { NoRepair = false, Repair = true };
 
 /* Write a derivation to the Nix store, and return its path. */
 StorePath writeDerivation(Store & store,
-    const Derivation & drv, RepairFlag repair = NoRepair);
+    const Derivation & drv,
+    RepairFlag repair = NoRepair,
+    bool readOnly = false);
 
 /* Read a derivation from a file. */
 Derivation parseDerivation(const Store & store, std::string && s, std::string_view name);
@@ -191,6 +204,16 @@ typedef std::map<StorePath, DrvHashModulo> DrvHashes;
 
 extern DrvHashes drvHashes; // FIXME: global, not thread-safe
 
+/* Memoisation of `readDerivation(..).resove()`. */
+typedef std::map<
+    StorePath,
+    std::optional<StorePath>
+> DrvPathResolutions;
+
+// FIXME: global, though at least thread-safe.
+// FIXME: arguably overlaps with hashDerivationModulo memo table.
+extern Sync<DrvPathResolutions> drvPathResolutions;
+
 bool wantOutput(const string & output, const std::set<string> & wanted);
 
 struct Source;

src/libstore/export-import.cc

@@ -45,7 +45,7 @@ void Store::exportPath(const StorePath & path, Sink & sink)
     teeSink
         << exportMagic
         << printStorePath(path);
-    writeStorePaths(*this, teeSink, info->referencesPossiblyToSelf());
+    worker_proto::write(*this, teeSink, info->referencesPossiblyToSelf());
     teeSink
         << (info->deriver ? printStorePath(*info->deriver) : "")
         << 0;
@@ -73,7 +73,7 @@ StorePaths Store::importPaths(Source & source, CheckSigsFlag checkSigs)
 
         //Activity act(*logger, lvlInfo, format("importing path '%s'") % info.path);
 
-        auto references = readStorePaths<StorePathSet>(*this, source);
+        auto references = worker_proto::read(*this, source, Phantom<StorePathSet> {});
         auto deriver = readString(source);
         auto narHash = hashString(htSHA256, *saved.s);
 

src/libstore/filetransfer.cc

@@ -113,6 +113,9 @@ struct curlFileTransfer : public FileTransfer
                 requestHeaders = curl_slist_append(requestHeaders, ("If-None-Match: " + request.expectedETag).c_str());
             if (!request.mimeType.empty())
                 requestHeaders = curl_slist_append(requestHeaders, ("Content-Type: " + request.mimeType).c_str());
+            for (auto it = request.headers.begin(); it != request.headers.end(); ++it){
+                requestHeaders = curl_slist_append(requestHeaders, fmt("%s: %s", it->first, it->second).c_str());
+            }
         }
 
         ~TransferItem()

src/libstore/filetransfer.hh

@@ -51,6 +51,7 @@ extern FileTransferSettings fileTransferSettings;
 struct FileTransferRequest
 {
     std::string uri;
+    Headers headers;
     std::string expectedETag;
     bool verifyTLS = true;
     bool head = false;

src/libstore/globals.hh

@@ -859,8 +859,54 @@ public:
           are loaded as plugins (non-recursively).
         )"};
 
-    Setting<std::string> githubAccessToken{this, "", "github-access-token",
+    Setting<StringMap> accessTokens{this, {}, "access-tokens",
-        "GitHub access token to get access to GitHub data through the GitHub API for `github:<..>` flakes."};
+        R"(
+          Access tokens used to access protected GitHub, GitLab, or
+          other locations requiring token-based authentication.
+
+          Access tokens are specified as a string made up of
+          space-separated `host=token` values.  The specific token
+          used is selected by matching the `host` portion against the
+          "host" specification of the input. The actual use of the
+          `token` value is determined by the type of resource being
+          accessed:
+
+          * Github: the token value is the OAUTH-TOKEN string obtained
+            as the Personal Access Token from the Github server (see
+            https://docs.github.com/en/developers/apps/authorizing-oath-apps).
+
+          * Gitlab: the token value is either the OAuth2 token or the
+            Personal Access Token (these are different types tokens
+            for gitlab, see
+            https://docs.gitlab.com/12.10/ee/api/README.html#authentication).
+            The `token` value should be `type:tokenstring` where
+            `type` is either `OAuth2` or `PAT` to indicate which type
+            of token is being specified.
+
+          Example `~/.config/nix/nix.conf`:
+
+          ```
+          access-tokens = "github.com=23ac...b289 gitlab.mycompany.com=PAT:A123Bp_Cd..EfG gitlab.com=OAuth2:1jklw3jk"
+          ```
+
+          Example `~/code/flake.nix`:
+
+          ```nix
+          input.foo = {
+            type = "gitlab";
+            host = "gitlab.mycompany.com";
+            owner = "mycompany";
+            repo = "pro";
+          };
+          ```
+
+          This example specifies three tokens, one each for accessing
+          github.com, gitlab.mycompany.com, and sourceforge.net.
+
+          The `input.foo` uses the "gitlab" fetcher, which might
+          requires specifying the token type along with the token
+          value.
+          )"};
 
     Setting<Strings> experimentalFeatures{this, {}, "experimental-features",
         "Experimental Nix features to enable."};

src/libstore/http-binary-cache-store.cc

@@ -73,6 +73,7 @@ public:
         if (forceHttp) ret.insert("file");
         return ret;
     }
+
 protected:
 
     void maybeDisable()

src/libstore/legacy-ssh-store.cc

@@ -121,7 +121,7 @@ struct LegacySSHStore : public Store, public virtual LegacySSHStoreConfig
             auto deriver = readString(conn->from);
             if (deriver != "")
                 info->deriver = parseStorePath(deriver);
-            info->setReferencesPossiblyToSelf(readStorePaths<StorePathSet>(*this, conn->from));
+            info->setReferencesPossiblyToSelf(worker_proto::read(*this, conn->from, Phantom<StorePathSet> {}));
             readLongLong(conn->from); // download size
             info->narSize = readLongLong(conn->from);
 
@@ -155,7 +155,7 @@ struct LegacySSHStore : public Store, public virtual LegacySSHStoreConfig
                 << printStorePath(info.path)
                 << (info.deriver ? printStorePath(*info.deriver) : "")
                 << info.narHash.to_string(Base16, false);
-            writeStorePaths(*this, conn->to, info.referencesPossiblyToSelf());
+            worker_proto::write(*this, conn->to, info.referencesPossiblyToSelf());
             conn->to
                 << info.registrationTime
                 << info.narSize
@@ -184,7 +184,7 @@ struct LegacySSHStore : public Store, public virtual LegacySSHStoreConfig
             conn->to
                 << exportMagic
                 << printStorePath(info.path);
-            writeStorePaths(*this, conn->to, info.referencesPossiblyToSelf());
+            worker_proto::write(*this, conn->to, info.referencesPossiblyToSelf());
             conn->to
                 << (info.deriver ? printStorePath(*info.deriver) : "")
                 << 0
@@ -300,10 +300,10 @@ public:
         conn->to
             << cmdQueryClosure
             << includeOutputs;
-        writeStorePaths(*this, conn->to, paths);
+        worker_proto::write(*this, conn->to, paths);
         conn->to.flush();
 
-        for (auto & i : readStorePaths<StorePathSet>(*this, conn->from))
+        for (auto & i : worker_proto::read(*this, conn->from, Phantom<StorePathSet> {}))
             out.insert(i);
     }
 
@@ -316,10 +316,10 @@ public:
             << cmdQueryValidPaths
             << false // lock
             << maybeSubstitute;
-        writeStorePaths(*this, conn->to, paths);
+        worker_proto::write(*this, conn->to, paths);
         conn->to.flush();
 
-        return readStorePaths<StorePathSet>(*this, conn->from);
+        return worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
     }
 
     void connect() override

src/libstore/local-store.cc

@@ -723,7 +723,7 @@ uint64_t LocalStore::queryValidPathId(State & state, const StorePath & path)
 {
     auto use(state.stmtQueryPathInfo.use()(printStorePath(path)));
     if (!use.next())
-        throw Error("path '%s' is not valid", printStorePath(path));
+        throw InvalidPath("path '%s' is not valid", printStorePath(path));
     return use.getInt(0);
 }
 
@@ -798,18 +798,58 @@ StorePathSet LocalStore::queryValidDerivers(const StorePath & path)
 }
 
 
-std::map<std::string, std::optional<StorePath>> LocalStore::queryPartialDerivationOutputMap(const StorePath & path)
+std::map<std::string, std::optional<StorePath>> LocalStore::queryPartialDerivationOutputMap(const StorePath & path_)
 {
+    auto path = path_;
     std::map<std::string, std::optional<StorePath>> outputs;
-    BasicDerivation drv = readDerivation(path);
+    Derivation drv = readDerivation(path);
     for (auto & [outName, _] : drv.outputs) {
         outputs.insert_or_assign(outName, std::nullopt);
     }
+    bool haveCached = false;
+    {
+        auto resolutions = drvPathResolutions.lock();
+        auto resolvedPathOptIter = resolutions->find(path);
+        if (resolvedPathOptIter != resolutions->end()) {
+            auto & [_, resolvedPathOpt] = *resolvedPathOptIter;
+            if (resolvedPathOpt)
+                path = *resolvedPathOpt;
+            haveCached = true;
+        }
+    }
+    /* can't just use else-if instead of `!haveCached` because we need to unlock
+       `drvPathResolutions` before it is locked in `Derivation::resolve`. */
+    if (!haveCached && drv.type() == DerivationType::CAFloating) {
+        /* Try resolve drv and use that path instead. */
+        auto attempt = drv.tryResolve(*this);
+        if (!attempt)
+            /* If we cannot resolve the derivation, we cannot have any path
+               assigned so we return the map of all std::nullopts. */
+            return outputs;
+        /* Just compute store path */
+        auto pathResolved = writeDerivation(*this, *std::move(attempt), NoRepair, true);
+        /* Store in memo table. */
+        /* FIXME: memo logic should not be local-store specific, should have
+           wrapper-method instead. */
+        drvPathResolutions.lock()->insert_or_assign(path, pathResolved);
+        path = std::move(pathResolved);
+    }
     return retrySQLite<std::map<std::string, std::optional<StorePath>>>([&]() {
         auto state(_state.lock());
 
-        auto useQueryDerivationOutputs(state->stmtQueryDerivationOutputs.use()
+        uint64_t drvId;
-            (queryValidPathId(*state, path)));
+        try {
+            drvId = queryValidPathId(*state, path);
+        } catch (InvalidPath &) {
+            /* FIXME? if the derivation doesn't exist, we cannot have a mapping
+               for it. */
+            return outputs;
+        }
+
+        auto useQueryDerivationOutputs {
+            state->stmtQueryDerivationOutputs.use()
+            (drvId)
+        };
 
         while (useQueryDerivationOutputs.next())
             outputs.insert_or_assign(

src/libstore/remote-store.cc

@@ -24,47 +24,19 @@
 
 namespace nix {
 
-
-template<> StorePathSet readStorePaths(const Store & store, Source & from)
-{
-    StorePathSet paths;
-    for (auto & i : readStrings<Strings>(from))
-        paths.insert(store.parseStorePath(i));
-    return paths;
-}
-
-void writeStorePaths(const Store & store, Sink & out, const StorePathSet & paths)
-{
-    out << paths.size();
-    for (auto & i : paths)
-        out << store.printStorePath(i);
-}
-
-
-StorePathCAMap readStorePathCAMap(const Store & store, Source & from)
-{
-    StorePathCAMap paths;
-    auto count = readNum<size_t>(from);
-    while (count--) {
-        auto path = store.parseStorePath(readString(from));
-        auto ca = parseContentAddressOpt(readString(from));
-        paths.insert_or_assign(path, ca);
-    }
-    return paths;
-}
-
-void writeStorePathCAMap(const Store & store, Sink & out, const StorePathCAMap & paths)
-{
-    out << paths.size();
-    for (auto & i : paths) {
-        out << store.printStorePath(i.first);
-        out << renderContentAddress(i.second);
-    }
-}
-
-
 namespace worker_proto {
 
+std::string read(const Store & store, Source & from, Phantom<std::string> _)
+{
+    return readString(from);
+}
+
+void write(const Store & store, Sink & out, const std::string & str)
+{
+    out << str;
+}
+
+
 StorePath read(const Store & store, Source & from, Phantom<StorePath> _)
 {
     return store.parseStorePath(readString(from));
@@ -76,19 +48,39 @@ void write(const Store & store, Sink & out, const StorePath & storePath)
 }
 
 
-template<>
+ContentAddress read(const Store & store, Source & from, Phantom<ContentAddress> _)
+{
+    return parseContentAddress(readString(from));
+}
+
+void write(const Store & store, Sink & out, const ContentAddress & ca)
+{
+    out << renderContentAddress(ca);
+}
+
+
 std::optional<StorePath> read(const Store & store, Source & from, Phantom<std::optional<StorePath>> _)
 {
     auto s = readString(from);
     return s == "" ? std::optional<StorePath> {} : store.parseStorePath(s);
 }
 
-template<>
 void write(const Store & store, Sink & out, const std::optional<StorePath> & storePathOpt)
 {
     out << (storePathOpt ? store.printStorePath(*storePathOpt) : "");
 }
 
+
+std::optional<ContentAddress> read(const Store & store, Source & from, Phantom<std::optional<ContentAddress>> _)
+{
+    return parseContentAddressOpt(readString(from));
+}
+
+void write(const Store & store, Sink & out, const std::optional<ContentAddress> & caOpt)
+{
+    out << (caOpt ? renderContentAddress(*caOpt) : "");
+}
+
 }
 
 
@@ -337,9 +329,9 @@ StorePathSet RemoteStore::queryValidPaths(const StorePathSet & paths, Substitute
         return res;
     } else {
         conn->to << wopQueryValidPaths;
-        writeStorePaths(*this, conn->to, paths);
+        worker_proto::write(*this, conn->to, paths);
         conn.processStderr();
-        return readStorePaths<StorePathSet>(*this, conn->from);
+        return worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
     }
 }
 
@@ -349,7 +341,7 @@ StorePathSet RemoteStore::queryAllValidPaths()
     auto conn(getConnection());
     conn->to << wopQueryAllValidPaths;
     conn.processStderr();
-    return readStorePaths<StorePathSet>(*this, conn->from);
+    return worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
 }
 
 
@@ -366,9 +358,9 @@ StorePathSet RemoteStore::querySubstitutablePaths(const StorePathSet & paths)
         return res;
     } else {
         conn->to << wopQuerySubstitutablePaths;
-        writeStorePaths(*this, conn->to, paths);
+        worker_proto::write(*this, conn->to, paths);
         conn.processStderr();
-        return readStorePaths<StorePathSet>(*this, conn->from);
+        return worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
     }
 }
 
@@ -390,7 +382,7 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, S
             auto deriver = readString(conn->from);
             if (deriver != "")
                 info.deriver = parseStorePath(deriver);
-            info.setReferencesPossiblyToSelf(i.first, readStorePaths<StorePathSet>(*this, conn->from));
+            info.setReferencesPossiblyToSelf(i.first, worker_proto::read(*this, conn->from, Phantom<StorePathSet> {}));
             info.downloadSize = readLongLong(conn->from);
             info.narSize = readLongLong(conn->from);
             infos.insert_or_assign(i.first, std::move(info));
@@ -403,9 +395,9 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, S
             StorePathSet paths;
             for (auto & path : pathsMap)
                 paths.insert(path.first);
-            writeStorePaths(*this, conn->to, paths);
+            worker_proto::write(*this, conn->to, paths);
         } else
-            writeStorePathCAMap(*this, conn->to, pathsMap);
+            worker_proto::write(*this, conn->to, pathsMap);
         conn.processStderr();
         size_t count = readNum<size_t>(conn->from);
         for (size_t n = 0; n < count; n++) {
@@ -414,7 +406,7 @@ void RemoteStore::querySubstitutablePathInfos(const StorePathCAMap & pathsMap, S
             auto deriver = readString(conn->from);
             if (deriver != "")
                 info.deriver = parseStorePath(deriver);
-            info.setReferencesPossiblyToSelf(path, readStorePaths<StorePathSet>(*this, conn->from));
+            info.setReferencesPossiblyToSelf(path, worker_proto::read(*this, conn->from, Phantom<StorePathSet> {}));
             info.downloadSize = readLongLong(conn->from);
             info.narSize = readLongLong(conn->from);
         }
@@ -429,7 +421,7 @@ ref<const ValidPathInfo> RemoteStore::readValidPathInfo(ConnectionHandle & conn,
     auto narHash = Hash::parseAny(readString(conn->from), htSHA256);
     auto info = make_ref<ValidPathInfo>(path, narHash);
     if (deriver != "") info->deriver = parseStorePath(deriver);
-    info->setReferencesPossiblyToSelf(readStorePaths<StorePathSet>(*this, conn->from));
+    info->setReferencesPossiblyToSelf(worker_proto::read(*this, conn->from, Phantom<StorePathSet> {}));
     conn->from >> info->registrationTime >> info->narSize;
     if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 16) {
         conn->from >> info->ultimate;
@@ -473,7 +465,7 @@ void RemoteStore::queryReferrers(const StorePath & path,
     auto conn(getConnection());
     conn->to << wopQueryReferrers << printStorePath(path);
     conn.processStderr();
-    for (auto & i : readStorePaths<StorePathSet>(*this, conn->from))
+    for (auto & i : worker_proto::read(*this, conn->from, Phantom<StorePathSet> {}))
         referrers.insert(i);
 }
 
@@ -483,7 +475,7 @@ StorePathSet RemoteStore::queryValidDerivers(const StorePath & path)
     auto conn(getConnection());
     conn->to << wopQueryValidDerivers << printStorePath(path);
     conn.processStderr();
-    return readStorePaths<StorePathSet>(*this, conn->from);
+    return worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
 }
 
 
@@ -495,7 +487,7 @@ StorePathSet RemoteStore::queryDerivationOutputs(const StorePath & path)
     }
     conn->to << wopQueryDerivationOutputs << printStorePath(path);
     conn.processStderr();
-    return readStorePaths<StorePathSet>(*this, conn->from);
+    return worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
 }
 
 
@@ -521,7 +513,6 @@ std::map<std::string, std::optional<StorePath>> RemoteStore::queryPartialDerivat
         }
         return ret;
     }
-
 }
 
 std::optional<StorePath> RemoteStore::queryPathFromHashPart(const std::string & hashPart)
@@ -551,7 +542,7 @@ ref<const ValidPathInfo> RemoteStore::addCAToStore(
             << wopAddToStore
             << name
             << renderContentAddressMethod(caMethod);
-        writeStorePaths(*this, conn->to, references);
+        worker_proto::write(*this, conn->to, references);
         conn->to << repair;
 
         conn.withFramedSink([&](Sink & sink) {
@@ -568,7 +559,7 @@ ref<const ValidPathInfo> RemoteStore::addCAToStore(
             [&](TextHashMethod thm) -> void {
                 std::string s = dump.drain();
                 conn->to << wopAddTextToStore << name << s;
-                writeStorePaths(*this, conn->to, references);
+                worker_proto::write(*this, conn->to, references);
                 conn.processStderr();
             },
             [&](FixedOutputHashMethod fohm) -> void {
@@ -637,7 +628,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
             sink
                 << exportMagic
                 << printStorePath(info.path);
-            writeStorePaths(*this, sink, info.referencesPossiblyToSelf());
+            worker_proto::write(*this, sink, info.referencesPossiblyToSelf());
             sink
                 << (info.deriver ? printStorePath(*info.deriver) : "")
                 << 0 // == no legacy signature
@@ -647,7 +638,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
 
         conn.processStderr(0, source2.get());
 
-        auto importedPaths = readStorePaths<StorePathSet>(*this, conn->from);
+        auto importedPaths = worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
         assert(importedPaths.empty() == 0); // doesn't include possible self reference
     }
 
@@ -656,7 +647,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
                  << printStorePath(info.path)
                  << (info.deriver ? printStorePath(*info.deriver) : "")
                  << info.narHash.to_string(Base16, false);
-        writeStorePaths(*this, conn->to, info.referencesPossiblyToSelf());
+        worker_proto::write(*this, conn->to, info.referencesPossiblyToSelf());
         conn->to << info.registrationTime << info.narSize
                  << info.ultimate << info.sigs << renderContentAddress(info.ca)
                  << repair << !checkSigs;
@@ -778,7 +769,7 @@ void RemoteStore::collectGarbage(const GCOptions & options, GCResults & results)
 
     conn->to
         << wopCollectGarbage << options.action;
-    writeStorePaths(*this, conn->to, options.pathsToDelete);
+    worker_proto::write(*this, conn->to, options.pathsToDelete);
     conn->to << options.ignoreLiveness
         << options.maxFreed
         /* removed options */
@@ -840,9 +831,9 @@ void RemoteStore::queryMissing(const std::vector<StorePathWithOutputs> & targets
             ss.push_back(p.to_string(*this));
         conn->to << ss;
         conn.processStderr();
-        willBuild = readStorePaths<StorePathSet>(*this, conn->from);
+        willBuild = worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
-        willSubstitute = readStorePaths<StorePathSet>(*this, conn->from);
+        willSubstitute = worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
-        unknown = readStorePaths<StorePathSet>(*this, conn->from);
+        unknown = worker_proto::read(*this, conn->from, Phantom<StorePathSet> {});
         conn->from >> downloadSize >> narSize;
         return;
     }

src/libstore/store-api.hh

@@ -454,9 +454,7 @@ public:
     // FIXME: remove?
     virtual StorePath addToStoreFromDump(Source & dump, const string & name,
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair)
-    {
+    { unsupported("addToStoreFromDump"); }
-        throw Error("addToStoreFromDump() is not supported by this store");
-    }
 
     /* Like addToStore, but the contents written to the output path is
        a regular file containing the given string. */
@@ -479,8 +477,38 @@ public:
         BuildMode buildMode = bmNormal);
 
     /* Build a single non-materialized derivation (i.e. not from an
-       on-disk .drv file). Note that ‘drvPath’ is only used for
+       on-disk .drv file).
-       informational purposes. */
+
+       ‘drvPath’ is used to deduplicate worker goals so it is imperative that
+       is correct. That said, it doesn't literally need to be store path that
+       would be calculated from writing this derivation to the store: it is OK
+       if it instead is that of a Derivation which would resolve to this (by
+       taking the outputs of it's input derivations and adding them as input
+       sources) such that the build time referenceable-paths are the same.
+
+       In the input-addressed case, we usually *do* use an "original"
+       unresolved derivations's path, as that is what will be used in the
+       `buildPaths` case. Also, the input-addressed output paths are verified
+       only by that contents of that specific unresolved derivation, so it is
+       nice to keep that information around so if the original derivation is
+       ever obtained later, it can be verified whether the trusted user in fact
+       used the proper output path.
+
+       In the content-addressed case, we want to always use the
+       resolved drv path calculated from the provided derivation. This serves
+       two purposes:
+
+         - It keeps the operation trustless, by ruling out a maliciously
+           invalid drv path corresponding to a non-resolution-equivalent
+           derivation.
+
+         - For the floating case in particular, it ensures that the derivation
+           to output mapping respects the resolution equivalence relation, so
+           one cannot choose different resolution-equivalent derivations to
+           subvert dependency coherence (i.e. the property that one doesn't end
+           up with multiple different versions of dependencies without
+           explicitly choosing to allow it).
+    */
     virtual BuildResult buildDerivation(const StorePath & drvPath, const BasicDerivation & drv,
         BuildMode buildMode = bmNormal) = 0;
 
@@ -517,7 +545,7 @@ public:
        - The collector isn't running, or it's just started but hasn't
          acquired the GC lock yet.  In that case we get and release
          the lock right away, then exit.  The collector scans the
-         permanent root and sees our's.
+         permanent root and sees ours.
 
        In either case the permanent root is seen by the collector. */
     virtual void syncWithGC() { };
@@ -802,6 +830,7 @@ struct StoreFactory
     std::function<std::shared_ptr<Store> (const std::string & scheme, const std::string & uri, const Store::Params & params)> create;
     std::function<std::shared_ptr<StoreConfig> ()> getConfig;
 };
+
 struct Implementations
 {
     static std::vector<StoreFactory> * registered;

src/libstore/worker-protocol.hh

@@ -66,10 +66,6 @@ typedef enum {
 class Store;
 struct Source;
 
-template<class T> T readStorePaths(const Store & store, Source & from);
-
-void writeStorePaths(const Store & store, Sink & out, const StorePathSet & paths);
-
 /* To guide overloading */
 template<typename T>
 struct Phantom {};
@@ -78,45 +74,63 @@ struct Phantom {};
 namespace worker_proto {
 /* FIXME maybe move more stuff inside here */
 
-StorePath read(const Store & store, Source & from, Phantom<StorePath> _);
+#define MAKE_WORKER_PROTO(TEMPLATE, T) \
-void write(const Store & store, Sink & out, const StorePath & storePath);
+    TEMPLATE T read(const Store & store, Source & from, Phantom< T > _); \
+    TEMPLATE void write(const Store & store, Sink & out, const T & str)
+
+MAKE_WORKER_PROTO(, std::string);
+MAKE_WORKER_PROTO(, StorePath);
+MAKE_WORKER_PROTO(, ContentAddress);
+
+MAKE_WORKER_PROTO(template<typename T>, std::set<T>);
+MAKE_WORKER_PROTO(template<typename T>, std::optional<T>);
+
+#define X_ template<typename K, typename V>
+#define Y_ std::map<K, V>
+MAKE_WORKER_PROTO(X_, Y_);
+#undef X_
+#undef Y_
 
 template<typename T>
-std::map<std::string, T> read(const Store & store, Source & from, Phantom<std::map<std::string, T>> _);
+std::set<T> read(const Store & store, Source & from, Phantom<std::set<T>> _)
-template<typename T>
-void write(const Store & store, Sink & out, const std::map<string, T> & resMap);
-template<typename T>
-std::optional<T> read(const Store & store, Source & from, Phantom<std::optional<T>> _);
-template<typename T>
-void write(const Store & store, Sink & out, const std::optional<T> & optVal);
-
-/* Specialization which uses and empty string for the empty case, taking
-   advantage of the fact StorePaths always serialize to a non-empty string.
-   This is done primarily for backwards compatability, so that StorePath <=
-   std::optional<StorePath>, where <= is the compatability partial order.
- */
-template<>
-void write(const Store & store, Sink & out, const std::optional<StorePath> & optVal);
-
-template<typename T>
-std::map<std::string, T> read(const Store & store, Source & from, Phantom<std::map<std::string, T>> _)
 {
-    std::map<string, T> resMap;
+    std::set<T> resSet;
-    auto size = (size_t)readInt(from);
+    auto size = readNum<size_t>(from);
     while (size--) {
-        auto thisKey = readString(from);
+        resSet.insert(read(store, from, Phantom<T> {}));
-        resMap.insert_or_assign(std::move(thisKey), nix::worker_proto::read(store, from, Phantom<T> {}));
+    }
+    return resSet;
+}
+
+template<typename T>
+void write(const Store & store, Sink & out, const std::set<T> & resSet)
+{
+    out << resSet.size();
+    for (auto & key : resSet) {
+        write(store, out, key);
+    }
+}
+
+template<typename K, typename V>
+std::map<K, V> read(const Store & store, Source & from, Phantom<std::map<K, V>> _)
+{
+    std::map<K, V> resMap;
+    auto size = readNum<size_t>(from);
+    while (size--) {
+        auto k = read(store, from, Phantom<K> {});
+        auto v = read(store, from, Phantom<V> {});
+        resMap.insert_or_assign(std::move(k), std::move(v));
     }
     return resMap;
 }
 
-template<typename T>
+template<typename K, typename V>
-void write(const Store & store, Sink & out, const std::map<string, T> & resMap)
+void write(const Store & store, Sink & out, const std::map<K, V> & resMap)
 {
     out << resMap.size();
     for (auto & i : resMap) {
-        out << i.first;
+        write(store, out, i.first);
-        nix::worker_proto::write(store, out, i.second);
+        write(store, out, i.second);
     }
 }
 
@@ -128,26 +142,29 @@ std::optional<T> read(const Store & store, Source & from, Phantom<std::optional<
     case 0:
         return std::nullopt;
     case 1:
-        return nix::worker_proto::read(store, from, Phantom<T> {});
+        return read(store, from, Phantom<T> {});
     default:
-        throw Error("got an invalid tag bit for std::optional: %#04x", tag);
+        throw Error("got an invalid tag bit for std::optional: %#04x", (size_t)tag);
     }
 }
 
 template<typename T>
 void write(const Store & store, Sink & out, const std::optional<T> & optVal)
 {
-    out << (optVal ? 1 : 0);
+    out << (uint64_t) (optVal ? 1 : 0);
     if (optVal)
-        nix::worker_proto::write(store, out, *optVal);
+        worker_proto::write(store, out, *optVal);
 }
 
+/* Specialization which uses and empty string for the empty case, taking
+   advantage of the fact these types always serialize to non-empty strings.
+   This is done primarily for backwards compatability, so that T <=
+   std::optional<T>, where <= is the compatability partial order, T is one of
+   the types below.
+ */
+MAKE_WORKER_PROTO(, std::optional<StorePath>);
+MAKE_WORKER_PROTO(, std::optional<ContentAddress>);
 
 }
 
-
-StorePathCAMap readStorePathCAMap(const Store & store, Source & from);
-
-void writeStorePathCAMap(const Store & store, Sink & out, const StorePathCAMap & paths);
-
 }

src/libutil/args.hh

@@ -192,7 +192,7 @@ public:
     {
         expectArgs({
             .label = label,
-            .optional = true,
+            .optional = optional,
             .handler = {dest}
         });
     }

src/libutil/config.cc

@@ -268,6 +268,26 @@ template<> std::string BaseSetting<StringSet>::to_string() const
     return concatStringsSep(" ", value);
 }
 
+template<> void BaseSetting<StringMap>::set(const std::string & str)
+{
+    auto kvpairs = tokenizeString<Strings>(str);
+    for (auto & s : kvpairs)
+    {
+        auto eq = s.find_first_of('=');
+        if (std::string::npos != eq)
+            value.emplace(std::string(s, 0, eq), std::string(s, eq + 1));
+        // else ignored
+    }
+}
+
+template<> std::string BaseSetting<StringMap>::to_string() const
+{
+    Strings kvstrs;
+    std::transform(value.begin(), value.end(), back_inserter(kvstrs),
+        [&](auto kvpair){ return kvpair.first + "=" + kvpair.second; });
+    return concatStringsSep(" ", kvstrs);
+}
+
 template class BaseSetting<int>;
 template class BaseSetting<unsigned int>;
 template class BaseSetting<long>;
@@ -278,6 +298,7 @@ template class BaseSetting<bool>;
 template class BaseSetting<std::string>;
 template class BaseSetting<Strings>;
 template class BaseSetting<StringSet>;
+template class BaseSetting<StringMap>;
 
 void PathSetting::set(const std::string & str)
 {

src/libutil/types.hh

@@ -24,6 +24,8 @@ typedef string Path;
 typedef list<Path> Paths;
 typedef set<Path> PathSet;
 
+typedef vector<std::pair<string, string>> Headers;
+
 /* Helper class to run code at startup. */
 template<typename T>
 struct OnStartup

src/libutil/url-parts.hh

@@ -7,7 +7,7 @@ namespace nix {
 
 // URI stuff.
 const static std::string pctEncoded = "(?:%[0-9a-fA-F][0-9a-fA-F])";
-const static std::string schemeRegex = "(?:[a-z+.-]+)";
+const static std::string schemeRegex = "(?:[a-z][a-z0-9+.-]*)";
 const static std::string ipv6AddressRegex = "(?:\\[[0-9a-fA-F:]+\\])";
 const static std::string unreservedRegex = "(?:[a-zA-Z0-9-._~])";
 const static std::string subdelimsRegex = "(?:[!$&'\"()*+,;=])";

src/nix-store/nix-store.cc

@@ -822,7 +822,7 @@ static void opServe(Strings opFlags, Strings opArgs)
             case cmdQueryValidPaths: {
                 bool lock = readInt(in);
                 bool substitute = readInt(in);
-                auto paths = readStorePaths<StorePathSet>(*store, in);
+                auto paths = worker_proto::read(*store, in, Phantom<StorePathSet> {});
                 if (lock && writeAllowed)
                     for (auto & path : paths)
                         store->addTempRoot(path);
@@ -852,19 +852,19 @@ static void opServe(Strings opFlags, Strings opArgs)
                         }
                 }
 
-                writeStorePaths(*store, out, store->queryValidPaths(paths));
+                worker_proto::write(*store, out, store->queryValidPaths(paths));
                 break;
             }
 
             case cmdQueryPathInfos: {
-                auto paths = readStorePaths<StorePathSet>(*store, in);
+                auto paths = worker_proto::read(*store, in, Phantom<StorePathSet> {});
                 // !!! Maybe we want a queryPathInfos?
                 for (auto & i : paths) {
                     try {
                         auto info = store->queryPathInfo(i);
                         out << store->printStorePath(info->path)
                             << (info->deriver ? store->printStorePath(*info->deriver) : "");
-                        writeStorePaths(*store, out, info->referencesPossiblyToSelf());
+                        worker_proto::write(*store, out, info->referencesPossiblyToSelf());
                         // !!! Maybe we want compression?
                         out << info->narSize // downloadSize
                             << info->narSize;
@@ -892,7 +892,7 @@ static void opServe(Strings opFlags, Strings opArgs)
 
             case cmdExportPaths: {
                 readInt(in); // obsolete
-                store->exportPaths(readStorePaths<StorePathSet>(*store, in), out);
+                store->exportPaths(worker_proto::read(*store, in, Phantom<StorePathSet> {}), out);
                 break;
             }
 
@@ -941,9 +941,9 @@ static void opServe(Strings opFlags, Strings opArgs)
             case cmdQueryClosure: {
                 bool includeOutputs = readInt(in);
                 StorePathSet closure;
-                store->computeFSClosure(readStorePaths<StorePathSet>(*store, in),
+                store->computeFSClosure(worker_proto::read(*store, in, Phantom<StorePathSet> {}),
                     closure, false, includeOutputs);
-                writeStorePaths(*store, out, closure);
+                worker_proto::write(*store, out, closure);
                 break;
             }
 
@@ -958,7 +958,7 @@ static void opServe(Strings opFlags, Strings opArgs)
                 };
                 if (deriver != "")
                     info.deriver = store->parseStorePath(deriver);
-                info.setReferencesPossiblyToSelf(readStorePaths<StorePathSet>(*store, in));
+                info.setReferencesPossiblyToSelf(worker_proto::read(*store, in, Phantom<StorePathSet> {}));
                 in >> info.registrationTime >> info.narSize >> info.ultimate;
                 info.sigs = readStrings<StringSet>(in);
                 info.ca = parseContentAddressOpt(readString(in));

src/nix/command.cc

@@ -152,7 +152,7 @@ void MixProfile::updateProfile(const Buildables & buildables)
                 for (auto & output : bfd.outputs) {
                     /* Output path should be known because we just tried to
                        build it. */
-                    assert(!output.second);
+                    assert(output.second);
                     result.push_back(*output.second);
                 }
             },

src/nix/hash.cc

@@ -44,6 +44,7 @@ struct CmdHash : Command
         switch (mode) {
         case FileIngestionMethod::Flat:
             d = "print cryptographic hash of a regular file";
+            break;
         case FileIngestionMethod::Recursive:
             d = "print cryptographic hash of the NAR serialisation of a path";
         };

src/nix/registry.cc

@@ -31,8 +31,8 @@ struct CmdRegistryList : StoreCommand
                     registry->type == Registry::User   ? "user  " :
                     registry->type == Registry::System ? "system" :
                     "global",
-                    entry.from.to_string(),
+                    entry.from.toURLString(),
-                    entry.to.to_string());
+                    entry.to.toURLString(attrsToQuery(entry.extraAttrs)));
             }
         }
     }

src/nix/run.cc

@@ -167,6 +167,14 @@ struct CmdRun : InstallableCommand, RunCommon
                 "To run Blender:",
                 "nix run blender-bin"
             },
+            Example{
+                "To run vim from nixpkgs:",
+                "nix run nixpkgs#vim"
+            },
+            Example{
+                "To run vim from nixpkgs with arguments:",
+                "nix run nixpkgs#vim -- --help"
+            },
         };
     }
 

tests/content-addressed.nix

@@ -29,4 +29,26 @@ rec {
     outputHashMode = "recursive";
     outputHashAlgo = "sha256";
   };
+  dependentCA = mkDerivation {
+    name = "dependent";
+    buildCommand = ''
+      echo "building a dependent derivation"
+      mkdir -p $out
+      echo ${rootCA}/hello > $out/dep
+    '';
+    __contentAddressed = true;
+    outputHashMode = "recursive";
+    outputHashAlgo = "sha256";
+  };
+  transitivelyDependentCA = mkDerivation {
+    name = "transitively-dependent";
+    buildCommand = ''
+      echo "building transitively-dependent"
+      cat ${dependentCA}/dep
+      echo ${dependentCA} > $out
+    '';
+    __contentAddressed = true;
+    outputHashMode = "recursive";
+    outputHashAlgo = "sha256";
+  };
 }

tests/content-addressed.sh

@@ -2,19 +2,26 @@
 
 source common.sh
 
-clearStore
-clearCache
-
-export REMOTE_STORE=file://$cacheDir
-
 drv=$(nix-instantiate --experimental-features ca-derivations ./content-addressed.nix -A rootCA --arg seed 1)
 nix --experimental-features 'nix-command ca-derivations' show-derivation --derivation "$drv" --arg seed 1
 
-commonArgs=("--experimental-features" "ca-derivations" "./content-addressed.nix" "-A" "rootCA" "--no-out-link")
+testDerivation () {
-out1=$(nix-build "${commonArgs[@]}" ./content-addressed.nix --arg seed 1)
+    local derivationPath=$1
-out2=$(nix-build "${commonArgs[@]}" ./content-addressed.nix --arg seed 2)
+    local commonArgs=("--experimental-features" "ca-derivations" "./content-addressed.nix" "-A" "$derivationPath" "--no-out-link")
+    local out1 out2
+    out1=$(nix-build "${commonArgs[@]}" --arg seed 1)
+    out2=$(nix-build "${commonArgs[@]}" --arg seed 2 "${secondSeedArgs[@]}")
+    test "$out1" == "$out2"
+}
 
-test $out1 == $out2
+testDerivation rootCA
+# The seed only changes the root derivation, and not it's output, so the
+# dependent derivations should only need to be built once.
+secondSeedArgs=(-j0)
+# Don't directly build depenentCA, that way we'll make sure we dodn't rely on
+# dependent derivations always being already built.
+#testDerivation dependentCA
+testDerivation transitivelyDependentCA
 
 nix-instantiate --experimental-features ca-derivations ./content-addressed.nix -A rootCA --arg seed 5
 nix-collect-garbage --experimental-features ca-derivations --option keep-derivations true

tests/tarball.sh

@@ -17,7 +17,7 @@ test_tarball() {
     local compressor="$2"
 
     tarball=$TEST_ROOT/tarball.tar$ext
-    (cd $TEST_ROOT && tar c tarball) | $compressor > $tarball
+    (cd $TEST_ROOT && tar cf - tarball) | $compressor > $tarball
 
     nix-env -f file://$tarball -qa --out-path | grep -q dependencies