From 597a8c736e2ed6f841b6b5d7f342453cc68d7355 Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Sun, 12 Nov 2023 00:53:25 -0600
Subject: [PATCH] [ox/mc] Fix alloca use in loop

---
 deps/ox/src/ox/mc/read.hpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/deps/ox/src/ox/mc/read.hpp b/deps/ox/src/ox/mc/read.hpp
index bba31b01..d96e4d76 100644
--- a/deps/ox/src/ox/mc/read.hpp
+++ b/deps/ox/src/ox/mc/read.hpp
@@ -248,12 +248,17 @@ constexpr Error MetalClawReaderTemplate<Reader>::field(const char*, HashMap<Stri
 			auto reader = child("");
 			auto &handler = *reader.interface();
 			oxReturnError(handler.setTypeInfo("List", 0, {}, static_cast<std::size_t>(len)));
-			for (std::size_t i = 0; i < len; ++i) {
+			// this loop body needs to be in a lambda because of the potential alloca call
+			constexpr auto loopBody = [](auto& handler) {
 				oxRequire(keyLen, handler.stringLength(nullptr));
 				auto wkey = ox_malloca(keyLen + 1, char, 0);
 				auto wkeyPtr = wkey.get();
 				oxReturnError(handler.fieldCString("", &wkeyPtr, keyLen + 1));
 				oxReturnError(handler.field("", &val->operator[](wkey.get())));
+				return OxError(0);
+			};
+			for (std::size_t i = 0; i < len; ++i) {
+				oxReturnError(loopBody(handler));
 			}
 		}
 	}