From d9c7f32a9c8644acef4569509be0de8f1c82ff6c Mon Sep 17 00:00:00 2001
From: Kane York <kanepyork@gmail.com>
Date: Sat, 12 Sep 2020 08:39:15 -0700
Subject: [PATCH] fix(3p/tvix): properly zero the largest member of Value
The static_assert is present to force us to change the constructor when a member grows.
Change-Id: Ifa4f4a03eb7ce13cff109cf26ecf0032045905e9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1972
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
---
third_party/nix/src/libexpr/value.hh | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/third_party/nix/src/libexpr/value.hh b/third_party/nix/src/libexpr/value.hh
index b5a1a33cb..980d9affb 100644
--- a/third_party/nix/src/libexpr/value.hh
+++ b/third_party/nix/src/libexpr/value.hh
@@ -105,7 +105,10 @@ struct Value {
NixFloat fpoint;
};
- Value() : type(tInt), integer(0) {}
+ Value() : type(tInt), attrs(nullptr) {
+ static_assert(offsetof(Value, attrs) + sizeof(attrs) == sizeof(Value));
+ }
+
Value(const Value& copy);
Value(Value&& move);
~Value() {}