Merge remote-tracking branch 'tweag/flake-test' into flakes

4 files changed, 56 insertions, 18 deletions

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 4bd1280ad..2d83af983 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -1972,6 +1972,14 @@ std::ostream & operator << (std::ostream & str, const ExternalValueBase & v) {
 
 EvalSettings evalSettings;
 
+EvalSettings::EvalSettings()
+{
+    if (flakeRegistry == "")
+        // FIXME: static initialization order fiasco. But this will go
+        // away when we switch to an online registry.
+        flakeRegistry = settings.nixDataDir + "/nix/flake-registry.json";
+}
+
 static GlobalConfig::Register r1(&evalSettings);
 
 
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 44988cd70..b0bf777fc 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -367,6 +367,11 @@ struct EvalSettings : Config
 
     Setting<Strings> allowedUris{this, {}, "allowed-uris",
         "Prefixes of URIs that builtin functions such as fetchurl and fetchGit are allowed to fetch."};
+
+    Setting<std::string> flakeRegistry{this, "", "flake-registry",
+        "Path or URI of the global flake registry."};
+
+    EvalSettings();
 };
 
 extern EvalSettings evalSettings;
diff --git a/src/libexpr/primops/flake.cc b/src/libexpr/primops/flake.cc
index dc8df7f6f..5e732b362 100644
--- a/src/libexpr/primops/flake.cc
+++ b/src/libexpr/primops/flake.cc
@@ -48,7 +48,7 @@ LockFile::FlakeEntry readFlakeEntry(nlohmann::json json)
 {
     FlakeRef flakeRef(json["uri"]);
     if (!flakeRef.isImmutable())
-        throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef);
+        throw Error("cannot use mutable flake '%s' in pure mode", flakeRef);
 
     LockFile::FlakeEntry entry(flakeRef);
 
@@ -126,8 +126,7 @@ void writeLockFile(const LockFile & lockFile, const Path & path)
 
 std::shared_ptr<FlakeRegistry> getGlobalRegistry()
 {
-    Path registryFile = settings.nixDataDir + "/nix/flake-registry.json";
-    return readRegistry(registryFile);
+    return readRegistry(evalSettings.flakeRegistry);
 }
 
 Path getUserRegistryPath()
@@ -237,8 +236,8 @@ static SourceInfo fetchFlake(EvalState & state, const FlakeRef & flakeRef, bool
         if (result.etag->size() != 42 || (*result.etag)[0] != '"' || (*result.etag)[41] != '"')
             throw Error("ETag header '%s' from '%s' is not a Git revision", *result.etag, url);
 
-        std::string rev = std::string(*result.etag, 1, result.etag->size() - 2);
-        const FlakeRef ref(resolvedRef.baseRef().to_string() + "/" + rev);
+        FlakeRef ref(resolvedRef.baseRef());
+        ref.rev = Hash(std::string(*result.etag, 1, result.etag->size() - 2), htSHA1);
         SourceInfo info(ref);
         info.storePath = result.path;
 
@@ -248,7 +247,9 @@ static SourceInfo fetchFlake(EvalState & state, const FlakeRef & flakeRef, bool
     // This downloads the entire git history
     else if (auto refData = std::get_if<FlakeRef::IsGit>(&resolvedRef.data)) {
         auto gitInfo = exportGit(state.store, refData->uri, resolvedRef.ref, resolvedRef.rev, "source");
-        const FlakeRef ref(resolvedRef.baseRef().to_string() + "/" + gitInfo.ref + "/" + gitInfo.rev.to_string(Base16, false));
+        FlakeRef ref(resolvedRef.baseRef());
+        ref.ref = gitInfo.ref;
+        ref.rev = gitInfo.rev;
         SourceInfo info(ref);
         info.storePath = gitInfo.storePath;
         info.revCount = gitInfo.revCount;
@@ -259,7 +260,9 @@ static SourceInfo fetchFlake(EvalState & state, const FlakeRef & flakeRef, bool
         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");
-        const FlakeRef ref(resolvedRef.baseRef().to_string() + "/" + gitInfo.ref + "/" + gitInfo.rev.to_string(Base16, false));
+        FlakeRef ref(resolvedRef.baseRef());
+        ref.ref = gitInfo.ref;
+        ref.rev = gitInfo.rev;
         SourceInfo info(ref);
         info.storePath = gitInfo.storePath;
         info.revCount = gitInfo.revCount;
diff --git a/src/libexpr/primops/flakeref.cc b/src/libexpr/primops/flakeref.cc
index 141d61c0d..784a0868e 100644
--- a/src/libexpr/primops/flakeref.cc
+++ b/src/libexpr/primops/flakeref.cc
@@ -147,30 +147,52 @@ FlakeRef::FlakeRef(const std::string & uri, bool allowRelative)
 std::string FlakeRef::to_string() const
 {
     std::string string;
-
-    if (auto refData = std::get_if<FlakeRef::IsAlias>(&data))
+    bool first = true;
+
+    auto addParam =
+        [&](const std::string & name, std::string value) {
+            string += first ? '?' : '&';
+            first = false;
+            string += name;
+            string += '=';
+            string += value; // FIXME: escaping
+        };
+
+    if (auto refData = std::get_if<FlakeRef::IsAlias>(&data)) {
         string = refData->alias;
+        if (ref) string += '/' + *ref;
+        if (rev) string += '/' + rev->to_string(Base16, false);
+    }
+
+    else if (auto refData = std::get_if<FlakeRef::IsPath>(&data)) {
+        assert(subdir == "");
+        assert(!rev);
+        assert(!ref);
+        return refData->path;
+    }
 
     else if (auto refData = std::get_if<FlakeRef::IsGitHub>(&data)) {
         assert(!(ref && rev));
         string = "github:" + refData->owner + "/" + refData->repo;
+        if (ref) { string += '/'; string += *ref; }
+        if (rev) { string += '/'; string += rev->to_string(Base16, false); }
+        if (subdir != "") addParam("dir", subdir);
     }
 
     else if (auto refData = std::get_if<FlakeRef::IsGit>(&data)) {
         assert(!rev || ref);
         string = refData->uri;
-    }
 
-    else if (auto refData = std::get_if<FlakeRef::IsPath>(&data))
-        return refData->path;
-
-    else abort();
+        if (ref) {
+            addParam("ref", *ref);
+            if (rev)
+                addParam("rev", rev->to_string(Base16, false));
+        }
 
-    // FIXME: need to use ?rev etc. for IsGit URIs.
-    string += (ref ? "/" + *ref : "") +
-              (rev ? "/" + rev->to_string(Base16, false) : "");
+        if (subdir != "") addParam("dir", subdir);
+    }
 
-    if (subdir != "") string += "?dir=" + subdir;
+    else abort();
 
     return string;
 }