From 930fa9b92ed8fcd8e976eeb3c519b6ce7c2a96bc Mon Sep 17 00:00:00 2001
From: Timo Kaufmann <timokau@zoho.com>
Date: Tue, 5 Mar 2019 21:55:51 +0100
Subject: [PATCH] python.pkgs.cysignals: propagate pari

This didn't cause issues earlier since all packages that depend on
cysignals have a pari dependency anyways.
---
 pkgs/development/python-modules/cysignals/default.nix | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pkgs/development/python-modules/cysignals/default.nix b/pkgs/development/python-modules/cysignals/default.nix
index c1f85ce75ac4..1cd55acdbeb8 100644
--- a/pkgs/development/python-modules/cysignals/default.nix
+++ b/pkgs/development/python-modules/cysignals/default.nix
@@ -31,12 +31,13 @@ buildPythonPackage rec {
     export PATH="$out/bin:$PATH"
   '';
 
-  buildInputs = lib.optionals pariSupport [
-    pari
-  ];
-
   propagatedBuildInputs = [
     cython
+  ] ++ lib.optionals pariSupport [
+    # When cysignals is built with pari, including cysignals into the
+    # buildInputs of another python package will cause cython to link against
+    # pari.
+    pari
   ];
 
   enableParallelBuilding = true;