From ba46c7d0f268622e29f94b99a8171e9a5be8b8b8 Mon Sep 17 00:00:00 2001
From: Cole Helbling <cole.helbling@determinate.systems>
Date: Sun, 7 Sep 2025 15:27:14 +0200
Subject: [PATCH] Fix flake registry ignoring `dir` parameter

This broke in e3042f10afb5f4e64ef9a5e08bef52b168cb4bf1.

(cherry picked from commit bccdb95a8661829322676d74a7344404467838fa)
---
 src/libfetchers/include/nix/fetchers/input-cache.hh | 1 +
 src/libfetchers/input-cache.cc                      | 6 ++++--
 src/libflake/flake.cc                               | 5 +++--
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/libfetchers/include/nix/fetchers/input-cache.hh b/src/libfetchers/include/nix/fetchers/input-cache.hh
index b2fc84245..ee2fa20c4 100644
--- a/src/libfetchers/include/nix/fetchers/input-cache.hh
+++ b/src/libfetchers/include/nix/fetchers/input-cache.hh
@@ -11,6 +11,7 @@ struct InputCache
         ref<SourceAccessor> accessor;
         Input resolvedInput;
         Input lockedInput;
+        Attrs extraAttrs;
     };
 
     CachedResult getAccessor(ref<Store> store, const Input & originalInput, UseRegistries useRegistries);
diff --git a/src/libfetchers/input-cache.cc b/src/libfetchers/input-cache.cc
index 1422c1d9a..c415b5417 100644
--- a/src/libfetchers/input-cache.cc
+++ b/src/libfetchers/input-cache.cc
@@ -8,6 +8,7 @@ namespace nix::fetchers {
 InputCache::CachedResult
 InputCache::getAccessor(ref<Store> store, const Input & originalInput, UseRegistries useRegistries)
 {
+    Attrs extraAttrs;
     auto fetched = lookup(originalInput);
     Input resolvedInput = originalInput;
 
@@ -17,7 +18,8 @@ InputCache::getAccessor(ref<Store> store, const Input & originalInput, UseRegist
             fetched.emplace(CachedInput{.lockedInput = lockedInput, .accessor = accessor});
         } else {
             if (useRegistries != UseRegistries::No) {
-                auto [res, extraAttrs] = lookupInRegistries(store, originalInput, useRegistries);
+                auto [res, extraAttrs_] = lookupInRegistries(store, originalInput, useRegistries);
+                extraAttrs = extraAttrs_;
                 resolvedInput = std::move(res);
                 fetched = lookup(resolvedInput);
                 if (!fetched) {
@@ -36,7 +38,7 @@ InputCache::getAccessor(ref<Store> store, const Input & originalInput, UseRegist
 
     debug("got tree '%s' from '%s'", fetched->accessor, fetched->lockedInput.to_string());
 
-    return {fetched->accessor, resolvedInput, fetched->lockedInput};
+    return {fetched->accessor, resolvedInput, fetched->lockedInput, extraAttrs};
 }
 
 struct InputCacheImpl : InputCache
diff --git a/src/libflake/flake.cc b/src/libflake/flake.cc
index b31bef211..572df6cc3 100644
--- a/src/libflake/flake.cc
+++ b/src/libflake/flake.cc
@@ -340,8 +340,9 @@ static Flake getFlake(
     // Fetch a lazy tree first.
     auto cachedInput = state.inputCache->getAccessor(state.store, originalRef.input, useRegistries);
 
-    auto resolvedRef = FlakeRef(std::move(cachedInput.resolvedInput), originalRef.subdir);
-    auto lockedRef = FlakeRef(std::move(cachedInput.lockedInput), originalRef.subdir);
+    auto subdir = fetchers::maybeGetStrAttr(cachedInput.extraAttrs, "dir").value_or(originalRef.subdir);
+    auto resolvedRef = FlakeRef(std::move(cachedInput.resolvedInput), subdir);
+    auto lockedRef = FlakeRef(std::move(cachedInput.lockedInput), subdir);
 
     // Parse/eval flake.nix to get at the input.self attributes.
     auto flake = readFlake(state, originalRef, resolvedRef, lockedRef, {cachedInput.accessor}, lockRootAttrPath);