From bcd298d39bffbb1a79ae5ce2c4eec8c45fa9f2a0 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Tue, 15 Nov 2022 17:57:40 +0100
Subject: [PATCH] libstore/derivation-goal: Elaborate a TODO for performance
 concern

---
 src/libstore/build/derivation-goal.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index 00e375fe9..2f22dbcec 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -538,7 +538,8 @@ void DerivationGoal::inputsRealised()
                    However, the impure derivations feature still relies on this
                    fragile way of doing things, because its builds do not have
                    a representation in the store, which is a usability problem
-                   in itself */
+                   in itself. When implementing this logic entirely with lookups
+                   make sure that they're cached. */
                 if (auto outPath = get(inputDrvOutputs, { depDrvPath, j })) {
                     worker.store.computeFSClosure(*outPath, inputPaths);
                 }