From 87c6c6cd4f547bc022da1972a6d95b78cdea95ea Mon Sep 17 00:00:00 2001
From: Martin Weinelt <hexa@darmstadt.ccc.de>
Date: Wed, 21 Jan 2026 17:32:24 +0100
Subject: [PATCH] python3Packages.astropy: fix OMP_NUM_THREADS going 0

---
 pkgs/development/python-modules/astropy/default.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/python-modules/astropy/default.nix b/pkgs/development/python-modules/astropy/default.nix
index d07f43684f89..5e30833f86d1 100644
--- a/pkgs/development/python-modules/astropy/default.nix
+++ b/pkgs/development/python-modules/astropy/default.nix
@@ -147,6 +147,10 @@ buildPythonPackage rec {
   preCheck = ''
     export HOME="$(mktemp -d)"
     export OMP_NUM_THREADS=$(( $NIX_BUILD_CORES / 4 ))
+    if [ $OMP_NUM_THREADS -eq 0 ]; then
+      export OMP_NUM_THREADS=1
+    fi
+
     # See https://github.com/astropy/astropy/issues/17649 and see
     # --hypothesis-profile=ci pytest flag below.
     cp conftest.py $out/