FlakeRegistry = FlakeRef -> FlakeRef

7 files changed, 102 insertions, 177 deletions

diff --git a/src/libexpr/primops/flake.cc b/src/libexpr/primops/flake.cc
index 729b1da95..145d79446 100644
--- a/src/libexpr/primops/flake.cc
+++ b/src/libexpr/primops/flake.cc
@@ -28,10 +28,8 @@ std::shared_ptr<FlakeRegistry> readRegistry(const Path & path)
         throw Error("flake registry '%s' has unsupported version %d", path, version);
 
     auto flakes = json["flakes"];
-    for (auto i = flakes.begin(); i != flakes.end(); ++i) {
-        FlakeRegistry::Entry entry{FlakeRef(i->value("uri", ""))};
-        registry->entries.emplace(i.key(), entry);
-    }
+    for (auto i = flakes.begin(); i != flakes.end(); ++i)
+        registry->entries.emplace(i.key(), FlakeRef(i->value("uri", "")));
 
     return registry;
 }
@@ -41,9 +39,8 @@ void writeRegistry(FlakeRegistry registry, Path path)
 {
     nlohmann::json json;
     json["version"] = 1;
-    for (auto elem : registry.entries) {
-        json["flakes"][elem.first] = { {"uri", elem.second.ref.to_string()} };
-    }
+    for (auto elem : registry.entries)
+        json["flakes"][elem.first.to_string()] = { {"uri", elem.second.to_string()} };
     createDirs(dirOf(path));
     writeFile(path, json.dump(4)); // The '4' is the number of spaces used in the indentation in the json file.
 }
@@ -127,106 +124,31 @@ void writeLockFile(LockFile lockFile, Path path)
     writeFile(path, json.dump(4)); // '4' = indentation in json file
 }
 
-Path getUserRegistryPath()
->>>>>>> Fixed dependency resolution
-{
-    FlakeRef flakeRef(json["uri"]);
-    if (!flakeRef.isImmutable())
-        throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef.to_string());
-
-    LockFile::FlakeEntry entry(flakeRef);
-
-    auto nonFlakeRequires = json["nonFlakeRequires"];
-
-    for (auto i = nonFlakeRequires.begin(); i != nonFlakeRequires.end(); ++i) {
-        FlakeRef flakeRef(i->value("uri", ""));
-        if (!flakeRef.isImmutable())
-            throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef.to_string());
-        entry.nonFlakeEntries.insert_or_assign(i.key(), flakeRef);
-    }
-
-    auto requires = json["requires"];
-
-    for (auto i = requires.begin(); i != requires.end(); ++i)
-        entry.flakeEntries.insert_or_assign(i.key(), readFlakeEntry(*i));
-
-    return entry;
-}
-
-LockFile readLockFile(const Path & path)
+std::shared_ptr<FlakeRegistry> getGlobalRegistry()
 {
-    LockFile lockFile;
-
-    if (!pathExists(path))
-        return lockFile;
-
-    auto json = nlohmann::json::parse(readFile(path));
-
-    auto version = json.value("version", 0);
-    if (version != 1)
-        throw Error("lock file '%s' has unsupported version %d", path, version);
-
-    auto nonFlakeRequires = json["nonFlakeRequires"];
-
-    for (auto i = nonFlakeRequires.begin(); i != nonFlakeRequires.end(); ++i) {
-        FlakeRef flakeRef(i->value("uri", ""));
-        if (!flakeRef.isImmutable())
-            throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef.to_string());
-        lockFile.nonFlakeEntries.insert_or_assign(i.key(), flakeRef);
-    }
-
-    auto requires = json["requires"];
-
-    for (auto i = requires.begin(); i != requires.end(); ++i)
-        lockFile.flakeEntries.insert_or_assign(i.key(), readFlakeEntry(*i));
-
-    return lockFile;
+    return std::make_shared<FlakeRegistry>();
 }
 
-nlohmann::json flakeEntryToJson(LockFile::FlakeEntry & entry)
+Path getUserRegistryPath()
 {
-    nlohmann::json json;
-    json["uri"] = entry.ref.to_string();
-    for (auto & x : entry.nonFlakeEntries)
-        json["nonFlakeRequires"][x.first]["uri"] = x.second.to_string();
-    for (auto & x : entry.flakeEntries)
-        json["requires"][x.first] = flakeEntryToJson(x.second);
-    return json;
+    return getHome() + "/.config/nix/registry.json";
 }
 
-void writeLockFile(LockFile lockFile, Path path)
+std::shared_ptr<FlakeRegistry> getUserRegistry()
 {
-    nlohmann::json json;
-    json["version"] = 1;
-    json["nonFlakeRequires"];
-    for (auto & x : lockFile.nonFlakeEntries)
-        json["nonFlakeRequires"][x.first]["uri"] = x.second.to_string();
-    for (auto & x : lockFile.flakeEntries)
-        json["requires"][x.first] = flakeEntryToJson(x.second);
-    createDirs(dirOf(path));
-    writeFile(path, json.dump(4)); // '4' = indentation in json file
+    return readRegistry(getUserRegistryPath());
 }
 
-Path getUserRegistryPath()
+std::shared_ptr<FlakeRegistry> getLocalRegistry()
 {
-    return getHome() + "/.config/nix/registry.json";
-}
-std::shared_ptr<FlakeRegistry> getGlobalRegistry()
-{
-    // FIXME: get from nixos.org.
     Path registryFile = settings.nixDataDir + "/nix/flake-registry.json";
     return readRegistry(registryFile);
 }
 
-std::shared_ptr<FlakeRegistry> getUserRegistry()
-{
-    return readRegistry(getUserRegistryPath());
-}
-
 std::shared_ptr<FlakeRegistry> getFlagRegistry()
 {
+    // TODO (Nick): Implement this.
     return std::make_shared<FlakeRegistry>();
-    // TODO: Implement this once the right flags are implemented.
 }
 
 const std::vector<std::shared_ptr<FlakeRegistry>> EvalState::getFlakeRegistries()
@@ -259,9 +181,9 @@ Value * makeFlakeRegistryValue(EvalState & state)
 
     for (auto & registry : registries) {
         for (auto & entry : registry->entries) {
-            auto vEntry = state.allocAttr(*v, entry.first);
+            auto vEntry = state.allocAttr(*v, entry.first.to_string());
             state.mkAttrs(*vEntry, 2);
-            mkString(*state.allocAttr(*vEntry, state.symbols.create("uri")), entry.second.ref.to_string());
+            mkString(*state.allocAttr(*vEntry, state.symbols.create("uri")), entry.second.to_string());
             vEntry->attrs->sort();
         }
     }
@@ -272,23 +194,30 @@ Value * makeFlakeRegistryValue(EvalState & state)
 }
 
 static FlakeRef lookupFlake(EvalState & state, const FlakeRef & flakeRef,
-    std::vector<std::shared_ptr<FlakeRegistry>> registries)
+    std::vector<std::shared_ptr<FlakeRegistry>> registries, std::vector<FlakeRef> pastSearches = {})
 {
-    if (auto refData = std::get_if<FlakeRef::IsAlias>(&flakeRef.data)) {
-        for (auto registry : registries) {
-            auto i = registry->entries.find(refData->alias);
-            if (i != registry->entries.end()) {
-                auto newRef = FlakeRef(i->second.ref);
-                if (!newRef.isDirect())
-                    throw Error("found indirect flake URI '%s' in the flake registry", i->second.ref.to_string());
-                if (flakeRef.ref) newRef.setRef(*flakeRef.ref);
-                if (flakeRef.rev) newRef.setRev(*flakeRef.rev);
-                return newRef;
+    for (std::shared_ptr<FlakeRegistry> registry : registries) {
+        auto i = registry->entries.find(flakeRef);
+        if (i != registry->entries.end()) {
+            auto newRef = i->second;
+            if (std::get_if<FlakeRef::IsAlias>(&flakeRef.data)) {
+                if (flakeRef.ref) newRef.ref = flakeRef.ref;
+                if (flakeRef.rev) newRef.rev = flakeRef.rev;
+            }
+            std::string errorMsg = "found cycle in flake registries: ";
+            for (FlakeRef oldRef : pastSearches) {
+                errorMsg += oldRef.to_string();
+                if (oldRef == newRef)
+                    throw Error(errorMsg);
+                errorMsg += " - ";
             }
+            pastSearches.push_back(newRef);
+            return lookupFlake(state, newRef, registries, pastSearches);
         }
-        throw Error("cannot find flake with alias '%s' in the flake registry or in the flake lock file", refData->alias);
-    } else
-        return flakeRef;
+    }
+    if (!flakeRef.isDirect())
+        throw Error("indirect flake URI '%s' is the result of a lookup", flakeRef.to_string());
+    return flakeRef;
 }
 
 struct FlakeSourceInfo
@@ -302,6 +231,7 @@ static FlakeSourceInfo fetchFlake(EvalState & state, const FlakeRef flakeRef, bo
 {
     FlakeRef fRef = lookupFlake(state, flakeRef, state.getFlakeRegistries());
 
+    // This only downloads only one revision of the repo, not the entire history.
     if (auto refData = std::get_if<FlakeRef::IsGitHub>(&fRef.data)) {
         if (evalSettings.pureEval && !impureIsAllowed && !fRef.isImmutable())
             throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", fRef.to_string());
@@ -332,6 +262,7 @@ static FlakeSourceInfo fetchFlake(EvalState & state, const FlakeRef flakeRef, bo
         return info;
     }
 
+    // This downloads the entire git history
     else if (auto refData = std::get_if<FlakeRef::IsGit>(&fRef.data)) {
         auto gitInfo = exportGit(state.store, refData->uri, fRef.ref,
             fRef.rev ? fRef.rev->to_string(Base16, false) : "", "source");
@@ -342,7 +273,7 @@ static FlakeSourceInfo fetchFlake(EvalState & state, const FlakeRef flakeRef, bo
         return info;
     }
 
-    else if (auto refData = std::get_if<FlakeRef::IsPath>(&directFlakeRef.data)) {
+    else if (auto refData = std::get_if<FlakeRef::IsPath>(&fRef.data)) {
         if (!pathExists(refData->path + "/.git"))
             throw Error("flake '%s' does not reference a Git repository", refData->path);
         auto gitInfo = exportGit(state.store, refData->path, {}, "", "source");
@@ -452,7 +383,7 @@ NonFlake getNonFlake(EvalState & state, const FlakeRef & flakeRef, FlakeAlias al
    dependencies.
    FIXME: this should return a graph of flakes.
 */
-Dependencies resolveFlake(EvalState & state, const FlakeRef & topRef, bool impureTopRef, bool isTopFlake = true)
+Dependencies resolveFlake(EvalState & state, const FlakeRef & topRef, bool impureTopRef, bool isTopFlake)
 {
     Flake flake = getFlake(state, topRef, isTopFlake && impureTopRef);
     Dependencies deps(flake);
@@ -461,7 +392,7 @@ Dependencies resolveFlake(EvalState & state, const FlakeRef & topRef, bool impur
         deps.nonFlakeDeps.push_back(getNonFlake(state, nonFlakeInfo.second, nonFlakeInfo.first));
 
     for (auto & newFlakeRef : flake.requires)
-        deps.flakeDeps.push_back(resolveFlake(state, newFlakeRef, impureTopRef, false));
+        deps.flakeDeps.push_back(resolveFlake(state, newFlakeRef, false));
 
     return deps;
 }
@@ -505,25 +436,23 @@ void updateLockFile(EvalState & state, Path path)
 
 // Return the `provides` of the top flake, while assigning to `v` the provides
 // of the dependencies as well.
-Value * makeFlakeValue(EvalState & state, FlakeUri flakeUri, Value & v)
+Value * makeFlakeValue(EvalState & state, const FlakeRef & flakeRef, bool impureTopRef, Value & v)
 {
-    FlakeRef flakeRef = FlakeRef(flakeUri);
-
-    Dependencies deps = resolveFlake(state, flakeRef, impure);
+    Dependencies deps = resolveFlake(state, flakeRef, impureTopRef);
 
-    // // FIXME: we should call each flake with only its dependencies
-    // // (rather than the closure of the top-level flake).
+    // FIXME: we should call each flake with only its dependencies
+    // (rather than the closure of the top-level flake).
 
     auto vResult = state.allocValue();
     // This will store the attribute set of the `nonFlakeRequires` and the `requires.provides`.
 
     state.mkAttrs(*vResult, deps.flakeDeps.size());
 
-    Value * vTop = 0;
+    Value * vTop = state.allocAttr(*vResult, deps.flake.id);
 
-    for (auto & flake : deps.flakeDeps) {
+    for (auto & dep : deps.flakeDeps) {
+        Flake flake = dep.flake;
         auto vFlake = state.allocAttr(*vResult, flake.id);
-        if (deps.topFlakeId == flake.id) vTop = vFlake;
 
         state.mkAttrs(*vFlake, 4);
 
@@ -532,7 +461,7 @@ Value * makeFlakeValue(EvalState & state, FlakeUri flakeUri, Value & v)
         state.store->assertStorePath(flake.path);
         mkString(*state.allocAttr(*vFlake, state.sOutPath), flake.path, {flake.path});
 
-        if (flake.second.revCount)
+        if (flake.revCount)
             mkInt(*state.allocAttr(*vFlake, state.symbols.create("revCount")), *flake.revCount);
 
         auto vProvides = state.allocAttr(*vFlake, state.symbols.create("provides"));
diff --git a/src/libexpr/primops/flake.hh b/src/libexpr/primops/flake.hh
index adf8b07af..9da065234 100644
--- a/src/libexpr/primops/flake.hh
+++ b/src/libexpr/primops/flake.hh
@@ -10,13 +10,7 @@ class EvalState;
 
 struct FlakeRegistry
 {
-    struct Entry
-    {
-        FlakeRef ref;
-        Entry(const FlakeRef & flakeRef) : ref(flakeRef) {};
-        Entry operator=(const Entry & entry) { return Entry(entry.ref); }
-    };
-    std::map<FlakeAlias, Entry> entries;
+    std::map<FlakeRef, FlakeRef> entries;
 };
 
 struct LockFile
@@ -79,7 +73,7 @@ struct Dependencies
     Dependencies(const Flake & flake) : flake(flake) {}
 };
 
-Dependencies resolveFlake(EvalState &, const FlakeRef &, bool impureTopRef, bool isTopFlake);
+Dependencies resolveFlake(EvalState &, const FlakeRef &, bool impureTopRef, bool isTopFlake = true);
 
 FlakeRegistry updateLockFile(EvalState &, Flake &);
 
diff --git a/src/libexpr/primops/flakeref.hh b/src/libexpr/primops/flakeref.hh
index 32904953a..d789a6f70 100644
--- a/src/libexpr/primops/flakeref.hh
+++ b/src/libexpr/primops/flakeref.hh
@@ -103,47 +103,59 @@ typedef std::string FlakeUri;
 
 struct FlakeRef
 {
-    std::optional<std::string> ref;
-    std::optional<Hash> rev;
-
     struct IsAlias
     {
         FlakeAlias alias;
+        bool operator<(const IsAlias & b) const { return alias < b.alias; };
+        bool operator==(const IsAlias & b) const { return alias == b.alias; };
     };
 
-    struct IsGitHub
-    {
+    struct IsGitHub {
         std::string owner, repo;
+        bool operator<(const IsGitHub & b) const {
+            return std::make_tuple(owner, repo) < std::make_tuple(b.owner, b.repo);
+        }
+        bool operator==(const IsGitHub & b) const {
+            return owner == b.owner && repo == b.repo;
+        }
     };
 
     // Git, Tarball
     struct IsGit
     {
         std::string uri;
+        bool operator<(const IsGit & b) const { return uri < b.uri; }
+        bool operator==(const IsGit & b) const { return uri == b.uri; }
     };
 
     struct IsPath
     {
         Path path;
+        bool operator<(const IsPath & b) const { return path < b.path; }
+        bool operator==(const IsPath & b) const { return path == b.path; }
     };
 
     // Git, Tarball
 
-    std::variant<IsFlakeId, IsGitHub, IsGit, IsPath> data;
+    std::variant<IsAlias, IsGitHub, IsGit, IsPath> data;
 
-    // Parse a flake URI.
-    FlakeRef(const std::string & uri, bool allowRelative = false);
+    std::optional<std::string> ref;
+    std::optional<Hash> rev;
 
-    // Default constructor
-    FlakeRef(const FlakeRef & flakeRef) : data(flakeRef.data) {};
+    bool operator<(const FlakeRef & flakeRef) const
+    {
+        return std::make_tuple(this->data, ref, rev) <
+            std::make_tuple(flakeRef.data, flakeRef.ref, flakeRef.rev);
+    }
+
+    bool operator==(const FlakeRef & flakeRef) const
+    {
+        return std::make_tuple(this->data, ref, rev) ==
+            std::make_tuple(flakeRef.data, flakeRef.ref, flakeRef.rev);
+    }
 
-    /* Unify two flake references so that the resulting reference
-       combines the information from both. For example,
-       "nixpkgs/<hash>" and "github:NixOS/nixpkgs" unifies to
-       "nixpkgs/master". May throw an exception if the references are
-       incompatible (e.g. "nixpkgs/<hash1>" and "nixpkgs/<hash2>",
-       where hash1 != hash2). */
-    FlakeRef(const FlakeRef & a, const FlakeRef & b);
+    // Parse a flake URI.
+    FlakeRef(const std::string & uri, bool allowRelative = false);
 
     // FIXME: change to operator <<.
     std::string to_string() const;
@@ -160,9 +172,5 @@ struct FlakeRef
     bool isImmutable() const;
 
     FlakeRef baseRef() const;
-
-    void setRef(std::optional<std::string> ref) { ref = ref; }
-
-    void setRev(std::optional<Hash> rev) { rev = rev; }
 };
 }
diff --git a/src/nix/build.cc b/src/nix/build.cc
index a2fc56e69..5a3d9d31a 100644
--- a/src/nix/build.cc
+++ b/src/nix/build.cc
@@ -1,4 +1,3 @@
-#include "primops/flake.hh"
 #include "eval.hh"
 #include "command.hh"
 #include "common-args.hh"
@@ -78,7 +77,7 @@ struct CmdBuild : MixDryRun, InstallablesCommand
                     }
         }
 
-        // std::string flakeUri = "";
+        // FlakeUri flakeUri = "";
         // if(updateLock)
         //     for (uint i = 0; i < installables.size(); i++)
         //         // if (auto flakeUri = installableToFlakeUri)
diff --git a/src/nix/command.hh b/src/nix/command.hh
index 83959bf9a..56e1e6f34 100644
--- a/src/nix/command.hh
+++ b/src/nix/command.hh
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "args.hh"
+#include "primops/flake.hh"
 #include "common-eval-args.hh"
 
 namespace nix {
@@ -46,7 +47,7 @@ struct GitRepoCommand : virtual Args
 
 struct FlakeCommand : virtual Args
 {
-    std::string flakeUri;
+    FlakeUri flakeUri;
 
     FlakeCommand()
     {
diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index df944a148..dbf0d3e9a 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -1,4 +1,3 @@
-#include "primops/flake.hh"
 #include "command.hh"
 #include "common-args.hh"
 #include "shared.hh"
@@ -29,11 +28,9 @@ struct CmdFlakeList : StoreCommand, MixEvalArgs
 
         stopProgressBar();
 
-        for (auto & registry : registries) {
-            for (auto & entry : registry->entries) {
-                std::cout << entry.first << " " << entry.second.ref.to_string() << "\n";
-            }
-        }
+        for (auto & registry : registries)
+            for (auto & entry : registry->entries)
+                std::cout << entry.first.to_string() << " " << entry.second.to_string() << "\n";
     }
 };
 
@@ -81,7 +78,7 @@ struct CmdFlakeDeps : FlakeCommand, MixJSON, StoreCommand, MixEvalArgs
 
         FlakeRef flakeRef(flakeUri);
 
-        Dependencies deps = resolveFlake(*evalState, flakeRef, true, true);
+        Dependencies deps = resolveFlake(*evalState, flakeRef, true);
 
         std::queue<Dependencies> todo;
         todo.push(deps);
@@ -135,15 +132,15 @@ struct CmdFlakeInfo : FlakeCommand, MixJSON, MixEvalArgs, StoreCommand
     void run(nix::ref<nix::Store> store) override
     {
         auto evalState = std::make_shared<EvalState>(searchPath, store);
-        nix::Flake flake = nix::getFlake(*evalState, FlakeRef(flakeUri));
+        nix::Flake flake = nix::getFlake(*evalState, FlakeRef(flakeUri), true);
         printFlakeInfo(flake, json);
     }
 };
 
 struct CmdFlakeAdd : MixEvalArgs, Command
 {
-    FlakeAlias flakeAlias;
-    FlakeUri flakeUri;
+    FlakeUri alias;
+    FlakeUri uri;
 
     std::string name() override
     {
@@ -157,25 +154,24 @@ struct CmdFlakeAdd : MixEvalArgs, Command
 
     CmdFlakeAdd()
     {
-        expectArg("flake-id", &flakeAlias);
-        expectArg("flake-uri", &flakeUri);
+        expectArg("alias", &alias);
+        expectArg("flake-uri", &uri);
     }
 
     void run() override
     {
-        FlakeRef newFlakeRef(flakeUri);
+        FlakeRef aliasRef(alias);
         Path userRegistryPath = getUserRegistryPath();
         auto userRegistry = readRegistry(userRegistryPath);
-        FlakeRegistry::Entry entry(newFlakeRef);
-        userRegistry->entries.erase(flakeAlias);
-        userRegistry->entries.insert_or_assign(flakeAlias, newFlakeRef);
+        userRegistry->entries.erase(aliasRef);
+        userRegistry->entries.insert_or_assign(aliasRef, FlakeRef(uri));
         writeRegistry(*userRegistry, userRegistryPath);
     }
 };
 
 struct CmdFlakeRemove : virtual Args, MixEvalArgs, Command
 {
-    FlakeAlias flakeAlias;
+    FlakeUri alias;
 
     std::string name() override
     {
@@ -189,21 +185,21 @@ struct CmdFlakeRemove : virtual Args, MixEvalArgs, Command
 
     CmdFlakeRemove()
     {
-        expectArg("flake-id", &flakeAlias);
+        expectArg("alias", &alias);
     }
 
     void run() override
     {
         Path userRegistryPath = getUserRegistryPath();
         auto userRegistry = readRegistry(userRegistryPath);
-        userRegistry->entries.erase(flakeAlias);
+        userRegistry->entries.erase(FlakeRef(alias));
         writeRegistry(*userRegistry, userRegistryPath);
     }
 };
 
 struct CmdFlakePin : virtual Args, StoreCommand, MixEvalArgs
 {
-    FlakeAlias flakeAlias;
+    FlakeUri alias;
 
     std::string name() override
     {
@@ -217,7 +213,7 @@ struct CmdFlakePin : virtual Args, StoreCommand, MixEvalArgs
 
     CmdFlakePin()
     {
-        expectArg("flake-id", &flakeAlias);
+        expectArg("alias", &alias);
     }
 
     void run(nix::ref<nix::Store> store) override
@@ -226,14 +222,13 @@ struct CmdFlakePin : virtual Args, StoreCommand, MixEvalArgs
 
         Path userRegistryPath = getUserRegistryPath();
         FlakeRegistry userRegistry = *readRegistry(userRegistryPath);
-        auto it = userRegistry.entries.find(flakeAlias);
+        auto it = userRegistry.entries.find(FlakeRef(alias));
         if (it != userRegistry.entries.end()) {
-            FlakeRef oldRef = it->second.ref;
-            it->second.ref = getFlake(*evalState, oldRef, true).ref;
+            it->second = getFlake(*evalState, it->second, true).ref;
             // The 'ref' in 'flake' is immutable.
             writeRegistry(userRegistry, userRegistryPath);
         } else
-            throw Error("the flake alias '%s' does not exist in the user registry", flakeAlias);
+            throw Error("the flake alias '%s' does not exist in the user registry", alias);
     }
 };
 
diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index e792ce96d..13a68a797 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -7,7 +7,6 @@
 #include "get-drvs.hh"
 #include "store-api.hh"
 #include "shared.hh"
-#include "primops/flake.hh"
 
 #include <regex>