From d7481b4b635b14c34d09f1f48b50f745eb868381 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Wed, 14 May 2025 18:21:39 -0400
Subject: [PATCH] Factor out `resolveStoreConfig`

Leverage #10766 to show how we can now resolve a store configuration
without actually opening the store for that resolved configuration.

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
---
 src/libstore/include/nix/store/store-open.hh |  5 +++++
 src/libstore/store-registration.cc           | 12 ++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/libstore/include/nix/store/store-open.hh b/src/libstore/include/nix/store/store-open.hh
index 8b3460cbf..7c1cda5be 100644
--- a/src/libstore/include/nix/store/store-open.hh
+++ b/src/libstore/include/nix/store/store-open.hh
@@ -15,6 +15,11 @@
 
 namespace nix {
 
+/**
+ * @return The store config denoted by `storeURI` (slight misnomer...).
+ */
+ref<StoreConfig> resolveStoreConfig(StoreReference && storeURI);
+
 /**
  * @return a Store object to access the Nix store denoted by
  * ‘uri’ (slight misnomer...).
diff --git a/src/libstore/store-registration.cc b/src/libstore/store-registration.cc
index 81cb80cc0..6362ac036 100644
--- a/src/libstore/store-registration.cc
+++ b/src/libstore/store-registration.cc
@@ -11,6 +11,13 @@ ref<Store> openStore(const std::string & uri, const Store::Config::Params & extr
 }
 
 ref<Store> openStore(StoreReference && storeURI)
+{
+    auto store = resolveStoreConfig(std::move(storeURI))->openStore();
+    store->init();
+    return store;
+}
+
+ref<StoreConfig> resolveStoreConfig(StoreReference && storeURI)
 {
     auto & params = storeURI.params;
 
@@ -58,10 +65,7 @@ ref<Store> openStore(StoreReference && storeURI)
     experimentalFeatureSettings.require(storeConfig->experimentalFeature());
     storeConfig->warnUnknownSettings();
 
-    auto store = storeConfig->openStore();
-    store->init();
-
-    return store;
+    return storeConfig;
 }
 
 std::list<ref<Store>> getDefaultSubstituters()