From 12c91a823e80b5e0a14a0abb0f34a6633b14bbfe Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Thu, 16 Nov 2023 11:27:31 +0100
Subject: [PATCH] maxPrimOpArity: 64 -> 8

This makes stack usage significantly more compact, allowing larger
amounts of data to be processed on the same stack.

PrimOp functions with more than 8 positional (curried) arguments
should use an attrset instead.
---
 src/libexpr/eval.hh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 5ee6359a8..ce798ed96 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -20,10 +20,10 @@ namespace nix {
 
 /**
  * We put a limit on primop arity because it lets us use a fixed size array on
- * the stack. 16 is already an impractical number of arguments. Use an attrset
+ * the stack. 8 is already an impractical number of arguments. Use an attrset
  * argument for such overly complicated functions.
  */
-constexpr size_t maxPrimOpArity = 64;
+constexpr size_t maxPrimOpArity = 8;
 
 class Store;
 class EvalState;