From 0c2fdd2f3c0f04bef4b5c74fbb02a5f8227c07df Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 19 Sep 2024 19:16:31 +0200
Subject: [PATCH 1/2] Fix missing GC root in zipAttrsWith

My SNAFU was that I assumed that all the `Value *`s we put in
`attrsSeen` are already reachable (which they are), but I forgot about
the `elems` pointer in `ListBuilder`.

Fixes #11547.
---
 src/libexpr/primops.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 9de8ff599eb..ed1597e5de3 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -3136,7 +3136,7 @@ static void prim_zipAttrsWith(EvalState & state, const PosIdx pos, Value * * arg
         std::optional<ListBuilder> list;
     };
 
-    std::map<Symbol, Item> attrsSeen;
+    std::map<Symbol, Item, std::less<Symbol>, traceable_allocator<std::pair<const Symbol, Item>>> attrsSeen;
 
     state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.zipAttrsWith");
     state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.zipAttrsWith");

From 4449b0da744c32cb9cbb06b661a5f5df4444497a Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 19 Sep 2024 19:52:47 +0200
Subject: [PATCH 2/2] Use HAVE_BOEHMGC

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
---
 src/libexpr/primops.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index ed1597e5de3..8d53a1dfd71 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -3136,7 +3136,11 @@ static void prim_zipAttrsWith(EvalState & state, const PosIdx pos, Value * * arg
         std::optional<ListBuilder> list;
     };
 
+#if HAVE_BOEHMGC
     std::map<Symbol, Item, std::less<Symbol>, traceable_allocator<std::pair<const Symbol, Item>>> attrsSeen;
+#else
+    std::map<Symbol, Item> attrsSeen;
+#endif
 
     state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.zipAttrsWith");
     state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.zipAttrsWith");