From 2310539e66e12579d4a4c09a460e85ed6ccbc952 Mon Sep 17 00:00:00 2001
From: eldritch horrors <pennae@lix.systems>
Date: Sun, 29 Jun 2025 20:35:14 +0200
Subject: [PATCH] Revert "libstore: don't delete already valid outputs after
 build"

This reverts commit 4ef56601b5a235949dc14b8852aa05580ffaefd9 as this is an insufficient fix for the critical correctness bug.

Change-Id: I7885c437ce4df25002d92654312b3b1bae53bfa3
---
 src/libstore/build/local-derivation-goal.cc | 16 +++++++++++-----
 tests/functional/linux-sandbox.sh           |  7 -------
 tests/functional/regression-fj883.nix       | 15 ---------------
 3 files changed, 11 insertions(+), 27 deletions(-)
 delete mode 100644 tests/functional/regression-fj883.nix

diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 7918ab8fa..8837ac25d 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -2098,11 +2098,6 @@ SingleDrvOutputs LocalDerivationGoal::registerOutputs()
                before this for loop. */
             if (*scratchPath != finalStorePath)
                 outputRewrites[std::string { scratchPath->hashPart() }] = std::string { finalStorePath.hashPart() };
-            /* Cancel automatic deletion of that output if it was a scratch output that we just
-             * registered. */
-            if (auto cleaner = scratchOutputsCleaner.extract(outputName)) {
-                cleaner.mapped().cancel();
-            }
         };
 
         auto orifu = get(outputReferencesIfUnregistered, outputName);
@@ -2418,6 +2413,10 @@ SingleDrvOutputs LocalDerivationGoal::registerOutputs()
            the next iteration */
         if (newInfo.ca) {
             localStore.registerValidPaths({{newInfo.path, newInfo}});
+            /* Cancel automatic deletion of that output if it was a scratch output. */
+            if (auto cleaner = scratchOutputsCleaner.extract(outputName)) {
+                cleaner.mapped().cancel();
+            }
         }
 
         infos.emplace(outputName, std::move(newInfo));
@@ -2446,6 +2445,13 @@ SingleDrvOutputs LocalDerivationGoal::registerOutputs()
             infos2.insert_or_assign(newInfo.path, newInfo);
         }
         localStore.registerValidPaths(infos2);
+
+        /* Cancel automatic deletion of that output if it was a scratch output that we just registered. */
+        for (auto & [outputName, _ ] : infos) {
+            if (auto cleaner = scratchOutputsCleaner.extract(outputName)) {
+                cleaner.mapped().cancel();
+            }
+        }
     }
 
     /* In case of a fixed-output derivation hash mismatch, throw an
diff --git a/tests/functional/linux-sandbox.sh b/tests/functional/linux-sandbox.sh
index 526605e5f..82f363a09 100644
--- a/tests/functional/linux-sandbox.sh
+++ b/tests/functional/linux-sandbox.sh
@@ -81,10 +81,3 @@ testCert present fixed-output "$certsymlink"
 
 # Symlinks should be added in the sandbox directly and not followed
 nix-sandbox-build symlink-derivation.nix
-
-# Regression fj#883: derivations outputs disappearing after rebuild
-# build the derivation for both its outputs and delete one of them.
-# simulates substitution or copying only one output from a builder.
-nix-store --delete $(nix-sandbox-build --no-out-link ./regression-fj883.nix -A base.lib)
-# build a derivation depending on previous one. this should succeed
-nix-sandbox-build --no-out-link ./regression-fj883.nix -A downstream
diff --git a/tests/functional/regression-fj883.nix b/tests/functional/regression-fj883.nix
deleted file mode 100644
index 2317145b7..000000000
--- a/tests/functional/regression-fj883.nix
+++ /dev/null
@@ -1,15 +0,0 @@
-with import ./config.nix;
-
-rec {
-  base = mkDerivation {
-    name = "base";
-    outputs = [ "out" "lib" ];
-    buildCommand = "echo > $out; echo > $lib";
-  };
-
-  downstream = mkDerivation {
-    name = "downstream";
-    deps = [ base.out base.lib ];
-    buildCommand = "echo $deps > $out";
-  };
-}