From 34a348a0590f88fece4c5a1773fbbc7b94c70445 Mon Sep 17 00:00:00 2001
From: Alexander Bantyev <balsoft@balsoft.ru>
Date: Mon, 2 Feb 2026 14:14:04 +0100
Subject: [PATCH] python3Packages.polars: fix the mimalloc flag

Since https://github.com/pola-rs/polars/pull/16365, the proper way to
use the mimalloc allocator is the allocator=mimalloc config options,
instead of use_mimalloc.

Update our packaging accordingly
---
 pkgs/development/python-modules/polars/default.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/python-modules/polars/default.nix b/pkgs/development/python-modules/polars/default.nix
index bdd9e72e8290..b4bb2b5ab9cb 100644
--- a/pkgs/development/python-modules/polars/default.nix
+++ b/pkgs/development/python-modules/polars/default.nix
@@ -97,7 +97,7 @@ buildPythonPackage rec {
 
     RUSTFLAGS = lib.concatStringsSep " " (
       lib.optionals (polarsMemoryAllocator.pname == "mimalloc") [
-        "--cfg use_mimalloc"
+        "--cfg allocator=\"mimalloc\""
       ]
     );
     RUST_BACKTRACE = true;