Use PathReferences more widely

29 files changed, 431 insertions, 205 deletions

diff --git a/perl/lib/Nix/Store.xs b/perl/lib/Nix/Store.xs
index 599921151..ea8bbaf34 100644
--- a/perl/lib/Nix/Store.xs
+++ b/perl/lib/Nix/Store.xs
@@ -111,7 +111,7 @@ SV * queryPathInfo(char * path, int base32)
             mXPUSHi(info->registrationTime);
             mXPUSHi(info->narSize);
             AV * arr = newAV();
-            for (auto & i : info->references)
+            for (auto & i : info->referencesPossiblyToSelf())
                 av_push(arr, newSVpv(store()->printStorePath(i).c_str(), 0));
             XPUSHs(sv_2mortal(newRV((SV *) arr)));
         } catch (Error & e) {
@@ -287,7 +287,13 @@ SV * makeFixedOutputPath(int recursive, char * algo, char * hash, char * name)
         try {
             auto h = Hash::parseAny(hash, parseHashType(algo));
             auto method = recursive ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
-            auto path = store()->makeFixedOutputPath(method, h, name);
+            auto path = store()->makeFixedOutputPath(name, FixedOutputInfo {
+                {
+                    .method = method,
+                    .hash = h,
+                },
+                {},
+            });
             XPUSHs(sv_2mortal(newSVpv(store()->printStorePath(path).c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 2b304aab0..c74b67658 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -1045,7 +1045,13 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
         std::optional<HashType> ht = parseHashTypeOpt(outputHashAlgo);
         Hash h = newHashAllowEmpty(*outputHash, ht);
 
-        auto outPath = state.store->makeFixedOutputPath(ingestionMethod, h, drvName);
+        auto outPath = state.store->makeFixedOutputPath(drvName, FixedOutputInfo {
+            {
+                .method = ingestionMethod,
+                .hash = h,
+            },
+            {},
+        });
         drv.env["out"] = state.store->printStorePath(outPath);
         drv.outputs.insert_or_assign("out", DerivationOutput {
                 .output = DerivationOutputCAFixed {
@@ -1764,7 +1770,13 @@ static void addPath(EvalState & state, const Pos & pos, const string & name, con
 
     std::optional<StorePath> expectedStorePath;
     if (expectedHash)
-        expectedStorePath = state.store->makeFixedOutputPath(method, *expectedHash, name);
+        expectedStorePath = state.store->makeFixedOutputPath(name, FixedOutputInfo {
+            {
+                .method = method,
+                .hash = *expectedHash,
+            },
+            {},
+        });
     Path dstPath;
     if (!expectedHash || !state.store->isValidPath(*expectedStorePath)) {
         dstPath = state.store->printStorePath(settings.readOnlyMode
diff --git a/src/libexpr/value-to-xml.hh b/src/libexpr/value-to-xml.hh
index 97657327e..c5f327bd8 100644
--- a/src/libexpr/value-to-xml.hh
+++ b/src/libexpr/value-to-xml.hh
@@ -10,5 +10,5 @@ namespace nix {
 
 void printValueAsXML(EvalState & state, bool strict, bool location,
     Value & v, std::ostream & out, PathSet & context);
-    
+
 }
diff --git a/src/libfetchers/fetchers.cc b/src/libfetchers/fetchers.cc
index 49851f7bc..67bb77d3e 100644
--- a/src/libfetchers/fetchers.cc
+++ b/src/libfetchers/fetchers.cc
@@ -198,7 +198,13 @@ StorePath Input::computeStorePath(Store & store) const
     auto narHash = getNarHash();
     if (!narHash)
         throw Error("cannot compute store path for mutable input '%s'", to_string());
-    return store.makeFixedOutputPath(FileIngestionMethod::Recursive, *narHash, "source");
+    return store.makeFixedOutputPath("source", FixedOutputInfo {
+        {
+            .method = FileIngestionMethod::Recursive,
+            .hash = *narHash,
+        },
+        {},
+    });
 }
 
 std::string Input::getType() const
diff --git a/src/libfetchers/tarball.cc b/src/libfetchers/tarball.cc
index ca49482a9..b3ee84810 100644
--- a/src/libfetchers/tarball.cc
+++ b/src/libfetchers/tarball.cc
@@ -71,14 +71,20 @@ DownloadFileResult downloadFile(
         dumpString(*res.data, sink);
         auto hash = hashString(htSHA256, *res.data);
         ValidPathInfo info {
-            store->makeFixedOutputPath(FileIngestionMethod::Flat, hash, name),
+            *store,
+            {
+                .name = name,
+                .info = FixedOutputInfo {
+                    {
+                        .method = FileIngestionMethod::Flat,
+                        .hash = hash,
+                    },
+                    {},
+                },
+            },
             hashString(htSHA256, *sink.s),
         };
         info.narSize = sink.s->size();
-        info.ca = FixedOutputHash {
-            .method = FileIngestionMethod::Flat,
-            .hash = hash,
-        };
         auto source = StringSource { *sink.s };
         store->addToStore(info, source, NoRepair, NoCheckSigs);
         storePath = std::move(info.path);
diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index d592f16dd..2d92e1c50 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -322,7 +322,17 @@ StorePath BinaryCacheStore::addToStoreFromDump(Source & dump, const string & nam
         unsupported("addToStoreFromDump");
     return addToStoreCommon(dump, repair, CheckSigs, [&](HashResult nar) {
         ValidPathInfo info {
-            makeFixedOutputPath(method, nar.first, name),
+            *this,
+            {
+                .name = name,
+                .info = FixedOutputInfo {
+                    {
+                        .method = method,
+                        .hash = nar.first,
+                    },
+                    {},
+                },
+            },
             nar.first,
         };
         info.narSize = nar.second;
@@ -412,14 +422,20 @@ StorePath BinaryCacheStore::addToStore(const string & name, const Path & srcPath
     });
     return addToStoreCommon(*source, repair, CheckSigs, [&](HashResult nar) {
         ValidPathInfo info {
-            makeFixedOutputPath(method, h, name),
+            *this,
+            {
+                .name = name,
+                .info = FixedOutputInfo {
+                    {
+                        .method = method,
+                        .hash = h,
+                    },
+                    {},
+                },
+            },
             nar.first,
         };
         info.narSize = nar.second;
-        info.ca = FixedOutputHash {
-            .method = method,
-            .hash = h,
-        };
         return info;
     })->path;
 }
@@ -428,17 +444,26 @@ StorePath BinaryCacheStore::addTextToStore(const string & name, const string & s
     const StorePathSet & references, RepairFlag repair)
 {
     auto textHash = hashString(htSHA256, s);
-    auto path = makeTextPath(name, textHash, references);
+    auto path = makeTextPath(name, TextInfo { textHash, references });
 
     if (!repair && isValidPath(path))
         return path;
 
     auto source = StringSource { s };
     return addToStoreCommon(source, repair, CheckSigs, [&](HashResult nar) {
-        ValidPathInfo info { path, nar.first };
+        ValidPathInfo info {
+            *this,
+            {
+                .name = name,
+                .info = TextInfo {
+                    { .hash = textHash },
+                    references,
+                },
+            },
+            nar.first,
+        };
         info.narSize = nar.second;
         info.ca = TextHash { textHash };
-        info.references = references;
         return info;
     })->path;
 }
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 97a832c6b..12ce6f2ec 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -4056,25 +4056,24 @@ void DerivationGoal::registerOutputs()
                 break;
             }
             auto got = caSink.finish().first;
-            auto refs = rewriteRefs();
             HashModuloSink narSink { htSHA256, oldHashPart };
             dumpPath(actualPath, narSink);
             auto narHashAndSize = narSink.finish();
             ValidPathInfo newInfo0 {
-                worker.store.makeFixedOutputPath(
-                    outputHash.method,
-                    got,
-                    outputPathName(drv->name, outputName),
-                    refs.references,
-                    refs.hasSelfReference),
+                worker.store,
+                {
+                    .name = outputPathName(drv->name, outputName),
+                    .info = FixedOutputInfo {
+                        {
+                            .method = outputHash.method,
+                            .hash = got,
+                        },
+                        rewriteRefs(),
+                    },
+                },
                 narHashAndSize.first,
             };
             newInfo0.narSize = narHashAndSize.second;
-            newInfo0.ca = FixedOutputHash {
-                .method = outputHash.method,
-                .hash = got,
-            };
-            static_cast<PathReferences<StorePath> &>(newInfo0) = refs;
 
             assert(newInfo0.ca);
             return newInfo0;
@@ -4861,7 +4860,10 @@ void SubstitutionGoal::tryNext()
     subs.pop_front();
 
     if (ca) {
-        subPath = sub->makeFixedOutputPathFromCA(storePath.name(), *ca);
+        subPath = sub->makeFixedOutputPathFromCA({
+            .name = std::string { storePath.name() },
+            .info = caWithoutRefs(*ca),
+        });
         if (sub->storeDir == worker.store.storeDir)
             assert(subPath == storePath);
     } else if (sub->storeDir != worker.store.storeDir) {
@@ -4891,7 +4893,7 @@ void SubstitutionGoal::tryNext()
     }
 
     if (info->path != storePath) {
-        if (info->isContentAddressed(*sub) && info->references.empty()) {
+        if (info->isContentAddressed(*sub) && info->references.empty() && !info->hasSelfReference) {
             auto info2 = std::make_shared<ValidPathInfo>(*info);
             info2->path = storePath;
             info = info2;
diff --git a/src/libstore/content-address.cc b/src/libstore/content-address.cc
index 90a3ad1f5..d68c60f4f 100644
--- a/src/libstore/content-address.cc
+++ b/src/libstore/content-address.cc
@@ -9,6 +9,7 @@ std::string FixedOutputHash::printMethodAlgo() const
     return makeFileIngestionPrefix(method) + printHashType(hash.type);
 }
 
+
 std::string makeFileIngestionPrefix(const FileIngestionMethod m)
 {
     switch (m) {
@@ -16,9 +17,8 @@ std::string makeFileIngestionPrefix(const FileIngestionMethod m)
         return "";
     case FileIngestionMethod::Recursive:
         return "r:";
-    default:
-        throw Error("impossible, caught both cases");
     }
+    assert(false);
 }
 
 std::string makeFixedOutputCA(FileIngestionMethod method, const Hash & hash)
@@ -32,10 +32,13 @@ std::string renderContentAddress(ContentAddress ca)
 {
     return std::visit(overloaded {
         [](TextHash th) {
-            return "text:" + th.hash.to_string(Base32, true);
+            return "text:"
+                + th.hash.to_string(Base32, true);
         },
         [](FixedOutputHash fsh) {
-            return makeFixedOutputCA(fsh.method, fsh.hash);
+            return "fixed:"
+                + makeFileIngestionPrefix(fsh.method)
+                + fsh.hash.to_string(Base32, true);
         }
     }, ca);
 }
@@ -142,7 +145,18 @@ Hash getContentAddressHash(const ContentAddress & ca)
         },
         [](FixedOutputHash fsh) {
             return fsh.hash;
-        }
+        },
+    }, ca);
+}
+
+ContentAddressWithReferences caWithoutRefs(const ContentAddress & ca) {
+    return std::visit(overloaded {
+        [&](TextHash h) -> ContentAddressWithReferences {
+            return TextInfo { h, {}};
+        },
+        [&](FixedOutputHash h) -> ContentAddressWithReferences {
+            return FixedOutputInfo { h, {}};
+        },
     }, ca);
 }
 
diff --git a/src/libstore/content-address.hh b/src/libstore/content-address.hh
index f6a6f5140..e15d76bd7 100644
--- a/src/libstore/content-address.hh
+++ b/src/libstore/content-address.hh
@@ -2,14 +2,20 @@
 
 #include <variant>
 #include "hash.hh"
+#include "path.hh"
 
 namespace nix {
 
+/*
+ * Mini content address
+ */
+
 enum struct FileIngestionMethod : uint8_t {
     Flat = false,
     Recursive = true
 };
 
+
 struct TextHash {
     Hash hash;
 };
@@ -41,10 +47,6 @@ typedef std::variant<
    ingested. */
 std::string makeFileIngestionPrefix(const FileIngestionMethod m);
 
-/* Compute the content-addressability assertion (ValidPathInfo::ca)
-   for paths created by makeFixedOutputPath() / addToStore(). */
-std::string makeFixedOutputCA(FileIngestionMethod method, const Hash & hash);
-
 std::string renderContentAddress(ContentAddress ca);
 
 std::string renderContentAddress(std::optional<ContentAddress> ca);
@@ -74,4 +76,96 @@ ContentAddressMethod parseContentAddressMethod(std::string_view rawCaMethod);
 
 std::string renderContentAddressMethod(ContentAddressMethod caMethod);
 
+/*
+ * References set
+ */
+
+template<typename Ref>
+struct PathReferences
+{
+    std::set<Ref> references;
+    bool hasSelfReference = false;
+
+    bool operator == (const PathReferences<Ref> & other) const
+    {
+        return references == other.references
+            && hasSelfReference == other.hasSelfReference;
+    }
+
+    /* Functions to view references + hasSelfReference as one set, mainly for
+       compatibility's sake. */
+    StorePathSet referencesPossiblyToSelf(const Ref & self) const;
+    void insertReferencePossiblyToSelf(const Ref & self, Ref && ref);
+    void setReferencesPossiblyToSelf(const Ref & self, std::set<Ref> && refs);
+};
+
+template<typename Ref>
+StorePathSet PathReferences<Ref>::referencesPossiblyToSelf(const Ref & self) const
+{
+    StorePathSet refs { references };
+    if (hasSelfReference)
+        refs.insert(self);
+    return refs;
+}
+
+template<typename Ref>
+void PathReferences<Ref>::insertReferencePossiblyToSelf(const Ref & self, Ref && ref)
+{
+    if (ref == self)
+        hasSelfReference = true;
+    else
+        references.insert(std::move(ref));
+}
+
+template<typename Ref>
+void PathReferences<Ref>::setReferencesPossiblyToSelf(const Ref & self, std::set<Ref> && refs)
+{
+    if (refs.count(self))
+        hasSelfReference = true;
+        refs.erase(self);
+
+    references = refs;
+}
+
+/*
+ * Full content address
+ *
+ * See the schema for store paths in store-api.cc
+ */
+
+// This matches the additional info that we need for makeTextPath
+struct TextInfo : TextHash {
+    // References for the paths, self references disallowed
+    StorePathSet references;
+};
+
+struct FixedOutputInfo : FixedOutputHash {
+    // References for the paths
+    PathReferences<StorePath> references;
+};
+
+typedef std::variant<
+    TextInfo,
+    FixedOutputInfo
+> ContentAddressWithReferences;
+
+ContentAddressWithReferences caWithoutRefs(const ContentAddress &);
+
+struct StorePathDescriptor {
+    std::string name;
+    ContentAddressWithReferences info;
+
+    bool operator == (const StorePathDescriptor & other) const
+    {
+        return name == other.name;
+        // FIXME second field
+    }
+
+    bool operator < (const StorePathDescriptor & other) const
+    {
+        return name < other.name;
+        // FIXME second field
+    }
+};
+
 }
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 07b4e772b..925a78083 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -27,8 +27,8 @@ std::optional<StorePath> DerivationOutput::path(const Store & store, std::string
 
 StorePath DerivationOutputCAFixed::path(const Store & store, std::string_view drvName, std::string_view outputName) const {
     return store.makeFixedOutputPath(
-        hash.method, hash.hash,
-        outputPathName(drvName, outputName));
+        outputPathName(drvName, outputName),
+        { hash, {} });
 }
 
 
diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh
index d48266774..be19aa300 100644
--- a/src/libstore/derivations.hh
+++ b/src/libstore/derivations.hh
@@ -130,8 +130,8 @@ struct Derivation : BasicDerivation
 
     /* 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.
+       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);
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 18545f659..e6b02cce6 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -567,7 +567,7 @@ void LocalStore::checkDerivationOutputs(const StorePath & drvPath, const Derivat
                 envHasRightPath(doia.path, i.first);
             },
             [&](DerivationOutputCAFixed dof) {
-                StorePath path = makeFixedOutputPath(dof.hash.method, dof.hash.hash, drvName);
+                StorePath path = makeFixedOutputPath(drvName, { dof.hash, {} });
                 envHasRightPath(path, i.first);
             },
             [&](DerivationOutputCAFloating _) {
@@ -923,7 +923,10 @@ void LocalStore::querySubstitutablePathInfos(const StorePathCAMap & paths, Subst
 
             // recompute store path so that we can use a different store root
             if (path.second) {
-                subPath = makeFixedOutputPathFromCA(path.first.name(), *path.second);
+                subPath = makeFixedOutputPathFromCA({
+                    .name = std::string { path.first.name() },
+                    .info = caWithoutRefs(*path.second),
+                });
                 if (sub->storeDir == storeDir)
                     assert(subPath == path.first);
                 if (subPath != path.first)
@@ -1164,7 +1167,18 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, const string & name,
 
     auto [hash, size] = hashSink->finish();
 
-    auto dstPath = makeFixedOutputPath(method, hash, name);
+    auto desc = StorePathDescriptor {
+        name,
+        FixedOutputInfo {
+            {
+                .method = method,
+                .hash = hash,
+            },
+            {},
+        },
+    };
+
+    auto dstPath = makeFixedOutputPathFromCA(desc);
 
     addTempRoot(dstPath);
 
@@ -1184,7 +1198,7 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, const string & name,
             autoGC();
 
             if (inMemory) {
-                 StringSource dumpSource { dump };
+                StringSource dumpSource { dump };
                 /* Restore from the NAR in memory. */
                 if (method == FileIngestionMethod::Recursive)
                     restorePath(realPath, dumpSource);
@@ -1209,9 +1223,8 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, const string & name,
 
             optimisePath(realPath);
 
-            ValidPathInfo info { dstPath, narHash.first };
+            ValidPathInfo info { *this, std::move(desc), narHash.first };
             info.narSize = narHash.second;
-            info.ca = FixedOutputHash { .method = method, .hash = hash };
             registerValidPath(info);
         }
 
@@ -1226,7 +1239,10 @@ StorePath LocalStore::addTextToStore(const string & name, const string & s,
     const StorePathSet & references, RepairFlag repair)
 {
     auto hash = hashString(htSHA256, s);
-    auto dstPath = makeTextPath(name, hash, references);
+    auto dstPath = makeTextPath(name, TextInfo {
+        { .hash = hash },
+        references,
+    });
 
     addTempRoot(dstPath);
 
diff --git a/src/libstore/nar-info.hh b/src/libstore/nar-info.hh
index 39ced76e5..fd37b85db 100644
--- a/src/libstore/nar-info.hh
+++ b/src/libstore/nar-info.hh
@@ -17,6 +17,9 @@ struct NarInfo : ValidPathInfo
     std::string system;
 
     NarInfo() = delete;
+    NarInfo(const Store & store, StorePathDescriptor && ca, Hash narHash)
+        : ValidPathInfo(store, std::move(ca), narHash)
+    { }
     NarInfo(StorePath && path, Hash narHash) : ValidPathInfo(std::move(path), narHash) { }
     NarInfo(const ValidPathInfo & info) : ValidPathInfo(info) { }
     NarInfo(const Store & store, const std::string & s, const std::string & whence);
diff --git a/src/libstore/path-info.hh b/src/libstore/path-info.hh
index 509f100d7..8c4791ac0 100644
--- a/src/libstore/path-info.hh
+++ b/src/libstore/path-info.hh
@@ -13,47 +13,6 @@ namespace nix {
 
 class Store;
 
-template<typename Ref>
-struct PathReferences
-{
-    std::set<Ref> references;
-    bool hasSelfReference = false;
-
-    /* Functions to view references + hasSelfReference as one set, mainly for
-       compatibility's sake. */
-    StorePathSet referencesPossiblyToSelf(const Ref & self) const;
-    void insertReferencePossiblyToSelf(const Ref & self, Ref && ref);
-    void setReferencesPossiblyToSelf(const Ref & self, std::set<Ref> && refs);
-};
-
-template<typename Ref>
-StorePathSet PathReferences<Ref>::referencesPossiblyToSelf(const Ref & self) const
-{
-    StorePathSet refs { references };
-    if (hasSelfReference)
-        refs.insert(self);
-    return refs;
-}
-
-template<typename Ref>
-void PathReferences<Ref>::insertReferencePossiblyToSelf(const Ref & self, Ref && ref)
-{
-    if (ref == self)
-        hasSelfReference = true;
-    else
-        references.insert(std::move(ref));
-}
-
-template<typename Ref>
-void PathReferences<Ref>::setReferencesPossiblyToSelf(const Ref & self, std::set<Ref> && refs)
-{
-    if (refs.count(self))
-        hasSelfReference = true;
-        refs.erase(self);
-
-    references = refs;
-}
-
 
 struct SubstitutablePathInfo : PathReferences<StorePath>
 {
@@ -68,7 +27,6 @@ struct ValidPathInfo : PathReferences<StorePath>
 {
     StorePath path;
     std::optional<StorePath> deriver;
-    // TODO document this
     Hash narHash;
     time_t registrationTime = 0;
     uint64_t narSize = 0; // 0 = unknown
@@ -117,6 +75,8 @@ struct ValidPathInfo : PathReferences<StorePath>
 
     void sign(const Store & store, const SecretKey & secretKey);
 
+    std::optional<StorePathDescriptor> fullStorePathDescriptorOpt() const;
+
     /* Return true iff the path is verifiably content-addressed. */
     bool isContentAddressed(const Store & store) const;
 
@@ -143,6 +103,9 @@ struct ValidPathInfo : PathReferences<StorePath>
     ValidPathInfo(StorePath && path, Hash narHash) : path(std::move(path)), narHash(narHash) { };
     ValidPathInfo(const StorePath & path, Hash narHash) : path(path), narHash(narHash) { };
 
+    ValidPathInfo(const Store & store,
+        StorePathDescriptor && ca, Hash narHash);
+
     virtual ~ValidPathInfo() { }
 };
 
diff --git a/src/libstore/path.hh b/src/libstore/path.hh
index b03a0f69d..5f239ceb6 100644
--- a/src/libstore/path.hh
+++ b/src/libstore/path.hh
@@ -1,6 +1,7 @@
 #pragma once
 
-#include "content-address.hh"
+#include <string_view>
+
 #include "types.hh"
 
 namespace nix {
@@ -64,8 +65,6 @@ typedef std::set<StorePath> StorePathSet;
 typedef std::vector<StorePath> StorePaths;
 typedef std::map<string, StorePath> OutputPathMap;
 
-typedef std::map<StorePath, std::optional<ContentAddress>> StorePathCAMap;
-
 /* Extension of derivations in the Nix store. */
 const std::string drvExtension = ".drv";
 
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 7041edbe5..5d63b8e3c 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -7,6 +7,7 @@
 #include "thread-pool.hh"
 #include "json.hh"
 #include "url.hh"
+#include "references.hh"
 #include "archive.hh"
 #include "callback.hh"
 
@@ -163,63 +164,61 @@ StorePath Store::makeOutputPath(std::string_view id,
 }
 
 
+/* Stuff the references (if any) into the type.  This is a bit
+   hacky, but we can't put them in `s' since that would be
+   ambiguous. */
 static std::string makeType(
     const Store & store,
     string && type,
-    const StorePathSet & references,
-    bool hasSelfReference = false)
+    const PathReferences<StorePath> & references)
 {
-    for (auto & i : references) {
+    for (auto & i : references.references) {
         type += ":";
         type += store.printStorePath(i);
     }
-    if (hasSelfReference) type += ":self";
+    if (references.hasSelfReference) type += ":self";
     return std::move(type);
 }
 
 
-StorePath Store::makeFixedOutputPath(
-    FileIngestionMethod method,
-    const Hash & hash,
-    std::string_view name,
-    const StorePathSet & references,
-    bool hasSelfReference) const
+StorePath Store::makeFixedOutputPath(std::string_view name, const FixedOutputInfo & info) const
 {
-    if (hash.type == htSHA256 && method == FileIngestionMethod::Recursive) {
-        return makeStorePath(makeType(*this, "source", references, hasSelfReference), hash, name);
+    if (info.hash.type == htSHA256 && info.method == FileIngestionMethod::Recursive) {
+        return makeStorePath(makeType(*this, "source", info.references), info.hash, name);
     } else {
-        assert(references.empty());
+        assert(info.references.references.size() == 0);
+        assert(!info.references.hasSelfReference);
         return makeStorePath("output:out",
             hashString(htSHA256,
                 "fixed:out:"
-                + makeFileIngestionPrefix(method)
-                + hash.to_string(Base16, true) + ":"),
+                + makeFileIngestionPrefix(info.method)
+                + info.hash.to_string(Base16, true) + ":"),
             name);
     }
 }
 
-StorePath Store::makeFixedOutputPathFromCA(std::string_view name, ContentAddress ca,
-    const StorePathSet & references, bool hasSelfReference) const
+
+StorePath Store::makeTextPath(std::string_view name, const TextInfo & info) const
+{
+    assert(info.hash.type == htSHA256);
+    return makeStorePath(
+        makeType(*this, "text", PathReferences<StorePath> { info.references }),
+        info.hash,
+        name);
+}
+
+
+StorePath Store::makeFixedOutputPathFromCA(const StorePathDescriptor & desc) const
 {
     // New template
     return std::visit(overloaded {
-        [&](TextHash th) {
-            return makeTextPath(name, th.hash, references);
+        [&](TextInfo ti) {
+            return makeTextPath(desc.name, ti);
         },
-        [&](FixedOutputHash fsh) {
-            return makeFixedOutputPath(fsh.method, fsh.hash, name, references, hasSelfReference);
+        [&](FixedOutputInfo foi) {
+            return makeFixedOutputPath(desc.name, foi);
         }
-    }, ca);
-}
-
-StorePath Store::makeTextPath(std::string_view name, const Hash & hash,
-    const StorePathSet & references) const
-{
-    assert(hash.type == htSHA256);
-    /* Stuff the references (if any) into the type.  This is a bit
-       hacky, but we can't put them in `s' since that would be
-       ambiguous. */
-    return makeStorePath(makeType(*this, "text", references), hash, name);
+    }, desc.info);
 }
 
 
@@ -229,14 +228,24 @@ std::pair<StorePath, Hash> Store::computeStorePathForPath(std::string_view name,
     Hash h = method == FileIngestionMethod::Recursive
         ? hashPath(hashAlgo, srcPath, filter).first
         : hashFile(hashAlgo, srcPath);
-    return std::make_pair(makeFixedOutputPath(method, h, name), h);
+    FixedOutputInfo caInfo {
+        {
+            .method = method,
+            .hash = h,
+        },
+        {},
+    };
+    return std::make_pair(makeFixedOutputPath(name, caInfo), h);
 }
 
 
 StorePath Store::computeStorePathForText(const string & name, const string & s,
     const StorePathSet & references) const
 {
-    return makeTextPath(name, hashString(htSHA256, s), references);
+    return makeTextPath(name, TextInfo {
+        { .hash = hashString(htSHA256, s) },
+        references,
+    });
 }
 
 
@@ -326,11 +335,20 @@ ValidPathInfo Store::addToStoreSlow(std::string_view name, const Path & srcPath,
         throw Error("hash mismatch for '%s'", srcPath);
 
     ValidPathInfo info {
-        makeFixedOutputPath(method, hash, name),
+        *this,
+        StorePathDescriptor {
+            std::string { name },
+            FixedOutputInfo {
+                {
+                    .method = method,
+                    .hash = hash,
+                },
+                {},
+            },
+        },
         narHash,
     };
     info.narSize = narSize;
-    info.ca = FixedOutputHash { .method = method, .hash = hash };
 
     if (!isValidPath(info.path)) {
         auto source = sinkToSource([&](Sink & scratchpadSink) {
@@ -496,7 +514,7 @@ void Store::queryPathInfo(const StorePath & storePath,
     auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));
 
     queryPathInfoUncached(storePath,
-        {[this, storePathS{printStorePath(storePath)}, hashPart, callbackPtr](std::future<std::shared_ptr<const ValidPathInfo>> fut) {
+        {[this, storePath, hashPart, callbackPtr](std::future<std::shared_ptr<const ValidPathInfo>> fut) {
 
             try {
                 auto info = fut.get();
@@ -509,11 +527,9 @@ void Store::queryPathInfo(const StorePath & storePath,
                     state_->pathInfoCache.upsert(hashPart, PathInfoCacheValue { .value = info });
                 }
 
-                auto storePath = parseStorePath(storePathS);
-
                 if (!info || !goodStorePath(storePath, info->path)) {
                     stats.narInfoMissing++;
-                    throw InvalidPath("path '%s' is not valid", storePathS);
+                    throw InvalidPath("path '%s' is not valid", printStorePath(storePath));
                 }
 
                 (*callbackPtr)(ref<const ValidPathInfo>(info));
@@ -536,13 +552,13 @@ StorePathSet Store::queryValidPaths(const StorePathSet & paths, SubstituteFlag m
     std::condition_variable wakeup;
     ThreadPool pool;
 
-    auto doQuery = [&](const Path & path) {
+    auto doQuery = [&](const StorePath & path) {
         checkInterrupt();
-        queryPathInfo(parseStorePath(path), {[path, this, &state_, &wakeup](std::future<ref<const ValidPathInfo>> fut) {
+        queryPathInfo(path, {[path, this, &state_, &wakeup](std::future<ref<const ValidPathInfo>> fut) {
             auto state(state_.lock());
             try {
                 auto info = fut.get();
-                state->valid.insert(parseStorePath(path));
+                state->valid.insert(path);
             } catch (InvalidPath &) {
             } catch (...) {
                 state->exc = std::current_exception();
@@ -554,7 +570,7 @@ StorePathSet Store::queryValidPaths(const StorePathSet & paths, SubstituteFlag m
     };
 
     for (auto & path : paths)
-        pool.enqueue(std::bind(doQuery, printStorePath(path))); // FIXME
+        pool.enqueue(std::bind(doQuery, path));
 
     pool.process();
 
@@ -737,7 +753,8 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
     // recompute store path on the chance dstStore does it differently
     if (info->ca && info->references.empty()) {
         auto info2 = make_ref<ValidPathInfo>(*info);
-        info2->path = dstStore->makeFixedOutputPathFromCA(info->path.name(), *info->ca);
+        info2->path = dstStore->makeFixedOutputPathFromCA(
+            info->fullStorePathDescriptorOpt().value());
         if (dstStore->storeDir == srcStore->storeDir)
             assert(info->path == info2->path);
         info = info2;
@@ -799,7 +816,8 @@ std::map<StorePath, StorePath> copyPaths(ref<Store> srcStore, ref<Store> dstStor
             auto info = srcStore->queryPathInfo(storePath);
             auto storePathForDst = storePath;
             if (info->ca && info->references.empty()) {
-                storePathForDst = dstStore->makeFixedOutputPathFromCA(storePath.name(), *info->ca);
+                storePathForDst = dstStore->makeFixedOutputPathFromCA(
+                    info->fullStorePathDescriptorOpt().value());
                 if (dstStore->storeDir == srcStore->storeDir)
                     assert(storePathForDst == storePath);
                 if (storePathForDst != storePath)
@@ -826,7 +844,8 @@ std::map<StorePath, StorePath> copyPaths(ref<Store> srcStore, ref<Store> dstStor
 
             auto storePathForDst = storePath;
             if (info->ca && info->references.empty()) {
-                storePathForDst = dstStore->makeFixedOutputPathFromCA(storePath.name(), *info->ca);
+                storePathForDst = dstStore->makeFixedOutputPathFromCA(
+                    info->fullStorePathDescriptorOpt().value());
                 if (dstStore->storeDir == srcStore->storeDir)
                     assert(storePathForDst == storePath);
                 if (storePathForDst != storePath)
@@ -947,19 +966,37 @@ void ValidPathInfo::sign(const Store & store, const SecretKey & secretKey)
     sigs.insert(secretKey.signDetached(fingerprint(store)));
 }
 
+std::optional<StorePathDescriptor> ValidPathInfo::fullStorePathDescriptorOpt() const
+{
+    if (! ca)
+        return std::nullopt;
+
+    return StorePathDescriptor {
+        .name = std::string { path.name() },
+        .info = std::visit(overloaded {
+            [&](TextHash th) {
+                TextInfo info { th };
+                assert(!hasSelfReference);
+                info.references = references;
+                return ContentAddressWithReferences { info };
+            },
+            [&](FixedOutputHash foh) {
+                FixedOutputInfo info { foh };
+                info.references = static_cast<PathReferences<StorePath>>(*this);
+                return ContentAddressWithReferences { info };
+            },
+        }, *ca),
+    };
+}
+
 bool ValidPathInfo::isContentAddressed(const Store & store) const
 {
-    if (! ca) return false;
+    auto fullCaOpt = fullStorePathDescriptorOpt();
 
-    auto caPath = std::visit(overloaded {
-        [&](TextHash th) {
-            assert(!hasSelfReference);
-            return store.makeTextPath(path.name(), th.hash, references);
-        },
-        [&](FixedOutputHash fsh) {
-            return store.makeFixedOutputPath(fsh.method, fsh.hash, path.name(), references, hasSelfReference);
-        }
-    }, *ca);
+    if (! fullCaOpt)
+        return false;
+
+    auto caPath = store.makeFixedOutputPathFromCA(*fullCaOpt);
 
     bool res = caPath == path;
 
@@ -997,6 +1034,26 @@ Strings ValidPathInfo::shortRefs() const
 }
 
 
+ValidPathInfo::ValidPathInfo(
+    const Store & store,
+    StorePathDescriptor && info,
+    Hash narHash)
+      : path(store.makeFixedOutputPathFromCA(info))
+      , narHash(narHash)
+{
+    std::visit(overloaded {
+        [this](TextInfo ti) {
+            this->references = ti.references;
+            this->ca = TextHash { std::move(ti) };
+        },
+        [this](FixedOutputInfo foi) {
+            *(static_cast<PathReferences<StorePath> *>(this)) = foi.references;
+            this->ca = FixedOutputHash { (FixedOutputHash) std::move(foi) };
+        },
+    }, std::move(info.info));
+}
+
+
 Derivation Store::derivationFromPath(const StorePath & drvPath)
 {
     ensurePath(drvPath);
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 854446987..e6a6053a3 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -170,6 +170,8 @@ struct BuildResult
     }
 };
 
+typedef std::map<StorePath, std::optional<ContentAddress>> StorePathCAMap;
+
 struct StoreConfig : public Config
 {
     using Config::Config;
@@ -313,17 +315,11 @@ public:
     StorePath makeOutputPath(std::string_view id,
         const Hash & hash, std::string_view name) const;
 
-    StorePath makeFixedOutputPath(FileIngestionMethod method,
-        const Hash & hash, std::string_view name,
-        const StorePathSet & references = {},
-        bool hasSelfReference = false) const;
+    StorePath makeFixedOutputPath(std::string_view name, const FixedOutputInfo & info) const;
 
-    StorePath makeTextPath(std::string_view name, const Hash & hash,
-        const StorePathSet & references = {}) const;
+    StorePath makeTextPath(std::string_view name, const TextInfo & info) const;
 
-    StorePath makeFixedOutputPathFromCA(std::string_view name, ContentAddress ca,
-        const StorePathSet & references = {},
-        bool hasSelfReference = false) const;
+    StorePath makeFixedOutputPathFromCA(const StorePathDescriptor & info) const;
 
     /* This is the preparatory part of addToStore(); it computes the
        store path to which srcPath is to be copied.  Returns the store
diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index 147602415..453fe60f9 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -244,7 +244,7 @@ nlohmann::json Args::toJSON()
     return res;
 }
 
-static void hashTypeCompleter(size_t index, std::string_view prefix) 
+static void hashTypeCompleter(size_t index, std::string_view prefix)
 {
     for (auto & type : hashTypes)
         if (hasPrefix(type, prefix))
diff --git a/src/libutil/error.hh b/src/libutil/error.hh
index f3babcbde..260ed3cf8 100644
--- a/src/libutil/error.hh
+++ b/src/libutil/error.hh
@@ -201,9 +201,8 @@ public:
 
     template<typename... Args>
     SysError(const Args & ... args)
-        : Error("")
+        : Error(""), errNo(errno)
     {
-        errNo = errno;
         auto hf = hintfmt(args...);
         err.hint = hintfmt("%1%: %2%", normaltxt(hf.str()), strerror(errNo));
     }
diff --git a/src/libutil/fmt.hh b/src/libutil/fmt.hh
index 6e69bdce2..11dbef9db 100644
--- a/src/libutil/fmt.hh
+++ b/src/libutil/fmt.hh
@@ -103,7 +103,7 @@ class hintformat
 public:
     hintformat(const string &format) :fmt(format)
     {
-        fmt.exceptions(boost::io::all_error_bits ^ 
+        fmt.exceptions(boost::io::all_error_bits ^
                        boost::io::too_many_args_bit ^
                        boost::io::too_few_args_bit);
     }
diff --git a/src/libutil/tests/logging.cc b/src/libutil/tests/logging.cc
index 7e53f17c6..d33bd7c1f 100644
--- a/src/libutil/tests/logging.cc
+++ b/src/libutil/tests/logging.cc
@@ -370,7 +370,7 @@ namespace nix {
 
       // constructing without access violation.
       ErrPos ep(invalid);
-    
+
       // assignment without access violation.
       ep = invalid;
 
diff --git a/src/libutil/types.hh b/src/libutil/types.hh
index 55d02bcf9..6c4c5ab74 100644
--- a/src/libutil/types.hh
+++ b/src/libutil/types.hh
@@ -4,6 +4,7 @@
 
 #include <list>
 #include <set>
+#include <string>
 #include <map>
 #include <vector>
 
diff --git a/src/nix-prefetch-url/nix-prefetch-url.cc b/src/nix-prefetch-url/nix-prefetch-url.cc
index 377ae03a8..99cc0cdec 100644
--- a/src/nix-prefetch-url/nix-prefetch-url.cc
+++ b/src/nix-prefetch-url/nix-prefetch-url.cc
@@ -161,8 +161,14 @@ static int _main(int argc, char * * argv)
         std::optional<StorePath> storePath;
         if (args.size() == 2) {
             expectedHash = Hash::parseAny(args[1], ht);
-            const auto recursive = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
-            storePath = store->makeFixedOutputPath(recursive, *expectedHash, name);
+            const auto method = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
+            storePath = store->makeFixedOutputPath(name, FixedOutputInfo {
+                {
+                    .method = method,
+                    .hash = *expectedHash,
+                },
+                {},
+            });
             if (store->isValidPath(*storePath))
                 hash = *expectedHash;
             else
diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index 9092dbd80..7981bbbdd 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -195,10 +195,10 @@ static void opAddFixed(Strings opFlags, Strings opArgs)
 /* Hack to support caching in `nix-prefetch-url'. */
 static void opPrintFixedPath(Strings opFlags, Strings opArgs)
 {
-    auto recursive = FileIngestionMethod::Flat;
+    auto method = FileIngestionMethod::Flat;
 
     for (auto i : opFlags)
-        if (i == "--recursive") recursive = FileIngestionMethod::Recursive;
+        if (i == "--recursive") method = FileIngestionMethod::Recursive;
         else throw UsageError("unknown flag '%1%'", i);
 
     if (opArgs.size() != 3)
@@ -209,7 +209,13 @@ static void opPrintFixedPath(Strings opFlags, Strings opArgs)
     string hash = *i++;
     string name = *i++;
 
-    cout << fmt("%s\n", store->printStorePath(store->makeFixedOutputPath(recursive, Hash::parseAny(hash, hashAlgo), name)));
+    cout << fmt("%s\n", store->printStorePath(store->makeFixedOutputPath(name, FixedOutputInfo {
+        {
+            .method = method,
+            .hash = Hash::parseAny(hash, hashAlgo),
+        },
+        {},
+    })));
 }
 
 
diff --git a/src/nix/add-to-store.cc b/src/nix/add-to-store.cc
index 023ffa4ed..86616d66b 100644
--- a/src/nix/add-to-store.cc
+++ b/src/nix/add-to-store.cc
@@ -69,14 +69,20 @@ struct CmdAddToStore : MixDryRun, StoreCommand
         }
 
         ValidPathInfo info {
-            store->makeFixedOutputPath(ingestionMethod, hash, *namePart),
+            *store,
+            StorePathDescriptor {
+                .name = *namePart,
+                .info = FixedOutputInfo {
+                    {
+                        .method = std::move(ingestionMethod),
+                        .hash = std::move(hash),
+                    },
+                    {},
+                },
+            },
             narHash,
         };
         info.narSize = sink.s->size();
-        info.ca = std::optional { FixedOutputHash {
-            .method = ingestionMethod,
-            .hash = hash,
-        } };
 
         if (!dryRun) {
             auto source = StringSource { *sink.s };
diff --git a/src/nix/bundle.cc b/src/nix/bundle.cc
index fc41da9e4..510df7504 100644
--- a/src/nix/bundle.cc
+++ b/src/nix/bundle.cc
@@ -91,7 +91,7 @@ struct CmdBundle : InstallableCommand
         mkString(*evalState->allocAttr(*arg, evalState->symbols.create("system")), settings.thisSystem.get());
 
         arg->attrs->sort();
- 
+
         auto vRes = evalState->allocValue();
         evalState->callFunction(*bundler.toValue(*evalState).first, *arg, *vRes, noPos);
 
diff --git a/src/nix/make-content-addressable.cc b/src/nix/make-content-addressable.cc
index 7737f6d91..7695c98f8 100644
--- a/src/nix/make-content-addressable.cc
+++ b/src/nix/make-content-addressable.cc
@@ -55,19 +55,15 @@ struct CmdMakeContentAddressable : StorePathsCommand, MixJSON
 
             StringMap rewrites;
 
-            StorePathSet references;
-            bool hasSelfReference = false;
+            PathReferences<StorePath> refs;
+            refs.hasSelfReference = oldInfo->hasSelfReference;
             for (auto & ref : oldInfo->references) {
-                if (ref == path)
-                    hasSelfReference = true;
-                else {
-                    auto i = remappings.find(ref);
-                    auto replacement = i != remappings.end() ? i->second : ref;
-                    // FIXME: warn about unremapped paths?
-                    if (replacement != ref)
-                        rewrites.insert_or_assign(store->printStorePath(ref), store->printStorePath(replacement));
-                    references.insert(std::move(replacement));
-                }
+                auto i = remappings.find(ref);
+                auto replacement = i != remappings.end() ? i->second : ref;
+                // FIXME: warn about unremapped paths?
+                if (replacement != ref)
+                    rewrites.insert_or_assign(store->printStorePath(ref), store->printStorePath(replacement));
+                refs.references.insert(std::move(replacement));
             }
 
             *sink.s = rewriteStrings(*sink.s, rewrites);
@@ -78,16 +74,20 @@ struct CmdMakeContentAddressable : StorePathsCommand, MixJSON
             auto narHash = hashModuloSink.finish().first;
 
             ValidPathInfo info {
-                store->makeFixedOutputPath(FileIngestionMethod::Recursive, narHash, path.name(), references, hasSelfReference),
+                *store,
+                StorePathDescriptor {
+                    .name = std::string { path.name() },
+                    .info = FixedOutputInfo {
+                        {
+                            .method = FileIngestionMethod::Recursive,
+                            .hash = narHash,
+                        },
+                        std::move(refs),
+                    },
+                },
                 narHash,
             };
-            info.references = std::move(references);
-            info.hasSelfReference = std::move(hasSelfReference);
             info.narSize = sink.s->size();
-            info.ca = FixedOutputHash {
-                .method = FileIngestionMethod::Recursive,
-                .hash = info.narHash,
-            };
 
             if (!json)
                 printInfo("rewrote '%s' to '%s'", pathS, store->printStorePath(info.path));
diff --git a/src/nix/profile.cc b/src/nix/profile.cc
index 7ce4dfe4c..41a4857fc 100644
--- a/src/nix/profile.cc
+++ b/src/nix/profile.cc
@@ -130,12 +130,21 @@ struct ProfileManifest
         auto narHash = hashString(htSHA256, *sink.s);
 
         ValidPathInfo info {
-            store->makeFixedOutputPath(FileIngestionMethod::Recursive, narHash, "profile", references),
+            *store,
+            StorePathDescriptor {
+                "profile",
+                FixedOutputInfo {
+                    {
+                        .method = FileIngestionMethod::Recursive,
+                        .hash = narHash,
+                    },
+                    { references },
+                },
+            },
             narHash,
         };
         info.references = std::move(references);
         info.narSize = sink.s->size();
-        info.ca = FixedOutputHash { .method = FileIngestionMethod::Recursive, .hash = info.narHash };
 
         auto source = StringSource { *sink.s };
         store->addToStore(info, source);
diff --git a/src/nix/verify.cc b/src/nix/verify.cc
index 26f755fd9..d189a2fd3 100644
--- a/src/nix/verify.cc
+++ b/src/nix/verify.cc
@@ -73,14 +73,14 @@ struct CmdVerify : StorePathsCommand
 
         ThreadPool pool;
 
-        auto doPath = [&](const Path & storePath) {
+        auto doPath = [&](const StorePath & storePath) {
             try {
                 checkInterrupt();
 
                 MaintainCount<std::atomic<size_t>> mcActive(active);
                 update();
 
-                auto info = store->queryPathInfo(store->parseStorePath(storePath));
+                auto info = store->queryPathInfo(storePath);
 
                 // Note: info->path can be different from storePath
                 // for binary cache stores when using --all (since we
@@ -178,7 +178,7 @@ struct CmdVerify : StorePathsCommand
         };
 
         for (auto & storePath : storePaths)
-            pool.enqueue(std::bind(doPath, store->printStorePath(storePath)));
+            pool.enqueue(std::bind(doPath, storePath));
 
         pool.process();