lockFlake(): Allow registry lookups for the top-level flake

Fixes #13050.

src/libcmd/installables.cc

@@ -40,7 +40,7 @@ void completeFlakeInputAttrPath(
     std::string_view prefix)
 {
     for (auto & flakeRef : flakeRefs) {
-        auto flake = flake::getFlake(*evalState, flakeRef, true);
+        auto flake = flake::getFlake(*evalState, flakeRef, fetchers::UseRegistries::All);
         for (auto & input : flake.inputs)
             if (hasPrefix(input.first, prefix))
                 completions.add(input.first);

src/libexpr/primops/fetchTree.cc

@@ -181,7 +181,7 @@ static void fetchTree(
     }
 
     if (!state.settings.pureEval && !input.isDirect() && experimentalFeatureSettings.isEnabled(Xp::Flakes))
-        input = lookupInRegistries(state.store, input).first;
+        input = lookupInRegistries(state.store, input, fetchers::UseRegistries::Limited).first;
 
     if (state.settings.pureEval && !input.isLocked()) {
         if (input.getNarHash())

src/libfetchers/include/nix/fetchers/input-cache.hh

@@ -2,6 +2,8 @@
 
 namespace nix::fetchers {
 
+enum class UseRegistries : int;
+
 struct InputCache
 {
     struct CachedResult
@@ -11,7 +13,7 @@ struct InputCache
         Input lockedInput;
     };
 
-    CachedResult getAccessor(ref<Store> store, const Input & originalInput, bool useRegistries);
+    CachedResult getAccessor(ref<Store> store, const Input & originalInput, UseRegistries useRegistries);
 
     struct CachedInput
     {

src/libfetchers/include/nix/fetchers/registry.hh

@@ -65,7 +65,11 @@ void overrideRegistry(
     const Input & to,
     const Attrs & extraAttrs);
 
-using RegistryFilter = std::function<bool(Registry::RegistryType)>;
+enum class UseRegistries : int {
+    No,
+    All,
+    Limited, // global and flag registry only
+};
 
 /**
  * Rewrite a flakeref using the registries. If `filter` is set, only
@@ -74,6 +78,6 @@ using RegistryFilter = std::function<bool(Registry::RegistryType)>;
 std::pair<Input, Attrs> lookupInRegistries(
     ref<Store> store,
     const Input & input,
-    const RegistryFilter & filter = {});
+    UseRegistries useRegistries);
 
 }

src/libfetchers/input-cache.cc

@@ -5,7 +5,8 @@
 
 namespace nix::fetchers {
 
-InputCache::CachedResult InputCache::getAccessor(ref<Store> store, const Input & originalInput, bool useRegistries)
+InputCache::CachedResult
+InputCache::getAccessor(ref<Store> store, const Input & originalInput, UseRegistries useRegistries)
 {
     auto fetched = lookup(originalInput);
     Input resolvedInput = originalInput;
@@ -15,13 +16,8 @@ InputCache::CachedResult InputCache::getAccessor(ref<Store> store, const Input &
             auto [accessor, lockedInput] = originalInput.getAccessor(store);
             fetched.emplace(CachedInput{.lockedInput = lockedInput, .accessor = accessor});
         } else {
-            if (useRegistries) {
+            if (useRegistries != UseRegistries::No) {
-                auto [res, extraAttrs] =
+                auto [res, extraAttrs] = lookupInRegistries(store, originalInput, useRegistries);
-                    lookupInRegistries(store, originalInput, [](fetchers::Registry::RegistryType type) {
-                        /* Only use the global registry and CLI flags
-                           to resolve indirect flakerefs. */
-                        return type == fetchers::Registry::Flag || type == fetchers::Registry::Global;
-                    });
                 resolvedInput = std::move(res);
                 fetched = lookup(resolvedInput);
                 if (!fetched) {

src/libfetchers/registry.cc

@@ -14,6 +14,8 @@ std::shared_ptr<Registry> Registry::read(
     const Settings & settings,
     const Path & path, RegistryType type)
 {
+    debug("reading registry '%s'", path);
+
     auto registry = std::make_shared<Registry>(settings, type);
 
     if (!pathExists(path))
@@ -179,29 +181,36 @@ Registries getRegistries(const Settings & settings, ref<Store> store)
 std::pair<Input, Attrs> lookupInRegistries(
     ref<Store> store,
     const Input & _input,
-    const RegistryFilter & filter)
+    UseRegistries useRegistries)
 {
     Attrs extraAttrs;
     int n = 0;
     Input input(_input);
 
+    if (useRegistries == UseRegistries::No)
+        return {input, extraAttrs};
+
  restart:
 
     n++;
     if (n > 100) throw Error("cycle detected in flake registry for '%s'", input.to_string());
 
     for (auto & registry : getRegistries(*input.settings, store)) {
-        if (filter && !filter(registry->type)) continue;
+        if (useRegistries == UseRegistries::Limited
+            && !(registry->type == fetchers::Registry::Flag || registry->type == fetchers::Registry::Global))
+            continue;
         // FIXME: O(n)
         for (auto & entry : registry->entries) {
             if (entry.exact) {
                 if (entry.from == input) {
+                    debug("resolved flakeref '%s' against registry %d exactly", input.to_string(), registry->type);
                     input = entry.to;
                     extraAttrs = entry.extraAttrs;
                     goto restart;
                 }
             } else {
                 if (entry.from.contains(input)) {
+                    debug("resolved flakeref '%s' against registry %d", input.to_string(), registry->type);
                     input = entry.to.applyOverrides(
                         !entry.from.getRef() && input.getRef() ? input.getRef() : std::optional<std::string>(),
                         !entry.from.getRev() && input.getRev() ? input.getRev() : std::optional<Hash>());

src/libflake/flake.cc

@@ -337,7 +337,7 @@ static FlakeRef applySelfAttrs(
 static Flake getFlake(
     EvalState & state,
     const FlakeRef & originalRef,
-    bool useRegistries,
+    fetchers::UseRegistries useRegistries,
     const InputAttrPath & lockRootAttrPath)
 {
     // Fetch a lazy tree first.
@@ -368,7 +368,7 @@ static Flake getFlake(
     return readFlake(state, originalRef, resolvedRef, lockedRef, state.storePath(storePath), lockRootAttrPath);
 }
 
-Flake getFlake(EvalState & state, const FlakeRef & originalRef, bool useRegistries)
+Flake getFlake(EvalState & state, const FlakeRef & originalRef, fetchers::UseRegistries useRegistries)
 {
     return getFlake(state, originalRef, useRegistries, {});
 }
@@ -393,8 +393,14 @@ LockedFlake lockFlake(
     experimentalFeatureSettings.require(Xp::Flakes);
 
     auto useRegistries = lockFlags.useRegistries.value_or(settings.useRegistries);
+    auto useRegistriesTop = useRegistries ? fetchers::UseRegistries::All : fetchers::UseRegistries::No;
+    auto useRegistriesInputs = useRegistries ? fetchers::UseRegistries::Limited : fetchers::UseRegistries::No;
 
-    auto flake = getFlake(state, topRef, useRegistries, {});
+    auto flake = getFlake(
+        state,
+        topRef,
+        useRegistriesTop,
+        {});
 
     if (lockFlags.applyNixConfig) {
         flake.config.apply(settings);
@@ -569,7 +575,11 @@ LockedFlake lockFlake(
                         if (auto resolvedPath = resolveRelativePath()) {
                             return readFlake(state, ref, ref, ref, *resolvedPath, inputAttrPath);
                         } else {
-                            return getFlake(state, ref, useRegistries, inputAttrPath);
+                            return getFlake(
+                                state,
+                                ref,
+                                useRegistriesInputs,
+                                inputAttrPath);
                         }
                     };
 
@@ -717,7 +727,10 @@ LockedFlake lockFlake(
                                 if (auto resolvedPath = resolveRelativePath()) {
                                     return {*resolvedPath, *input.ref};
                                 } else {
-                                    auto cachedInput = state.inputCache->getAccessor(state.store, input.ref->input, useRegistries);
+                                    auto cachedInput = state.inputCache->getAccessor(
+                                        state.store,
+                                        input.ref->input,
+                                        useRegistriesInputs);
 
                                     auto lockedRef = FlakeRef(std::move(cachedInput.lockedInput), input.ref->subdir);
 
@@ -834,7 +847,10 @@ LockedFlake lockFlake(
                            repo, so we should re-read it. FIXME: we could
                            also just clear the 'rev' field... */
                         auto prevLockedRef = flake.lockedRef;
-                        flake = getFlake(state, topRef, useRegistries);
+                        flake = getFlake(
+                            state,
+                            topRef,
+                            useRegistriesTop);
 
                         if (lockFlags.commitLockFile &&
                             flake.lockedRef.input.getRev() &&

src/libflake/flakeref.cc

@@ -37,9 +37,9 @@ std::ostream & operator << (std::ostream & str, const FlakeRef & flakeRef)
 
 FlakeRef FlakeRef::resolve(
     ref<Store> store,
-    const fetchers::RegistryFilter & filter) const
+    fetchers::UseRegistries useRegistries) const
 {
-    auto [input2, extraAttrs] = lookupInRegistries(store, input, filter);
+    auto [input2, extraAttrs] = lookupInRegistries(store, input, useRegistries);
     return FlakeRef(std::move(input2), fetchers::maybeGetStrAttr(extraAttrs, "dir").value_or(subdir));
 }
 

src/libflake/include/nix/flake/flake.hh

@@ -115,7 +115,7 @@ struct Flake
     }
 };
 
-Flake getFlake(EvalState & state, const FlakeRef & flakeRef, bool useRegistries);
+Flake getFlake(EvalState & state, const FlakeRef & flakeRef, fetchers::UseRegistries useRegistries);
 
 /**
  * Fingerprint of a locked flake; used as a cache key.

src/libflake/include/nix/flake/flakeref.hh

@@ -65,7 +65,7 @@ struct FlakeRef
 
     FlakeRef resolve(
         ref<Store> store,
-        const fetchers::RegistryFilter & filter = {}) const;
+        fetchers::UseRegistries useRegistries = fetchers::UseRegistries::All) const;
 
     static FlakeRef fromAttrs(
         const fetchers::Settings & fetchSettings,

tests/functional/flakes/flakes.sh

@@ -223,7 +223,7 @@ mv "$registry.tmp" "$registry"
 # Ensure that locking ignores the user registry.
 mkdir -p "$TEST_HOME/.config/nix"
 ln -sfn "$registry" "$TEST_HOME/.config/nix/registry.json"
-nix flake metadata flake1
+nix flake metadata --flake-registry '' flake1
 expectStderr 1 nix flake update --flake-registry '' --flake "$flake3Dir" | grepQuiet "cannot find flake 'flake:flake1' in the flake registries"
 rm "$TEST_HOME/.config/nix/registry.json"