From 1c4e392c64939ca961458cfb15a9da1e4d883b22 Mon Sep 17 00:00:00 2001
From: Guillaume Maudoux <layus.on@gmail.com>
Date: Thu, 25 Apr 2024 00:44:47 +0200
Subject: [PATCH] Compute fingerprint only if needed

As per Eelco's review comments

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
---
 src/libcmd/installables.cc | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/libcmd/installables.cc b/src/libcmd/installables.cc
index 5683e1afa..e5c981629 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -443,9 +443,8 @@ ref<eval_cache::EvalCache> openEvalCache(
     EvalState & state,
     std::shared_ptr<flake::LockedFlake> lockedFlake)
 {
-    auto fingerprint = lockedFlake->getFingerprint(state.store);
-    auto hash = evalSettings.useEvalCache && evalSettings.pureEval
-        ? fingerprint
+    auto fingerprint = evalSettings.useEvalCache && evalSettings.pureEval
+        ? lockedFlake->getFingerprint(state.store)
         : std::nullopt;
     auto rootLoader = [&state, lockedFlake]()
         {
@@ -472,7 +471,7 @@ ref<eval_cache::EvalCache> openEvalCache(
         }
         return search->second;
     } else {
-        return make_ref<nix::eval_cache::EvalCache>(hash, state, rootLoader);
+        return make_ref<nix::eval_cache::EvalCache>(std::nullopt, state, rootLoader);
     }
 }