From 3c610df550be35d9696efe9dd3217a6e1ec100f2 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Fri, 26 Sep 2025 00:22:54 -0400
Subject: [PATCH] Delete scratch data for CA derivation that produced
 already-extant output

In the case where the store object doesn't exist, we do correctly move
(rather than copy) the scratch data into place. In this case, the
destination store object already exists, but we still want to clean up
after ourselves.
---
 src/libstore/unix/build/derivation-builder.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/libstore/unix/build/derivation-builder.cc b/src/libstore/unix/build/derivation-builder.cc
index 770bdad4d..3a6f71555 100644
--- a/src/libstore/unix/build/derivation-builder.cc
+++ b/src/libstore/unix/build/derivation-builder.cc
@@ -1712,6 +1712,8 @@ SingleDrvOutputs DerivationBuilderImpl::registerOutputs()
                 /* Path already exists because CA path produced by something
                    else. No moving needed. */
                 assert(newInfo.ca);
+                /* Can delete our scratch copy now. */
+                deletePath(actualPath);
             } else {
                 auto destPath = store.toRealPath(finalDestPath);
                 deletePath(destPath);