daemon: Filter build-chroot-dirs entries that conflict with derivation outputs.

Fixes https://github.com/NixOS/nixpkgs/issues/9504.

Note that this means we may have a non-functional /bin/sh in the
chroot while rebuilding Bash or one of its dependencies. Ideally those
packages don't rely on /bin/sh though.

1 files changed, 4 insertions, 4 deletions

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index ab33f57265..64678a5594 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -1870,13 +1870,13 @@ void DerivationGoal::startBuilder()
             }
         }
 
-        /* If we're repairing or checking, it's possible that we're
+        /* If we're repairing, checking or rebuilding part of a
+           multiple-outputs derivation, it's possible that we're
            rebuilding a path that is in settings.dirsInChroot
            (typically the dependencies of /bin/sh).  Throw them
            out. */
-        if (buildMode != bmNormal)
-            foreach (DerivationOutputs::iterator, i, drv.outputs)
-                dirsInChroot.erase(i->second.path);
+        for (auto & i : drv.outputs)
+            dirsInChroot.erase(i.second.path);
 
 #else
         throw Error("chroot builds are not supported on this platform");