From 31bb833ca2b358a8d557e1a8cfae13f2214e4b60 Mon Sep 17 00:00:00 2001
From: Maximilian Bosch <maximilian@mbosch.me>
Date: Mon, 24 Aug 2026 01:24:00 +0200
Subject: [PATCH] python3Packages.mypy: fix build w/ glibc-2.44
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Otherwiwse a bunch of tests break with
"warning: ‘_POSIX_C_SOURCE’ redefined".

Apparently this now happens, if software doesn't adhere to the rule of
`Python.h` having to be included first[1]. The applied patch focuses on
Python 3.15 support, but also happens to fix that.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2416110
---
 pkgs/development/python-modules/mypy/default.nix | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/pkgs/development/python-modules/mypy/default.nix b/pkgs/development/python-modules/mypy/default.nix
index 68587c7c345f..a50eb9c32761 100644
--- a/pkgs/development/python-modules/mypy/default.nix
+++ b/pkgs/development/python-modules/mypy/default.nix
@@ -6,6 +6,7 @@
   gitUpdater,
   pythonAtLeast,
   isPyPy,
+  fetchpatch,
 
   # build-system
   pathspec,
@@ -49,6 +50,15 @@ buildPythonPackage rec {
     hash = "sha256-sm/pxQGxH5XuPH7B8i3fpp30KaFU9aSp6BT67UcDPvU=";
   };
 
+  patches = [
+    # fix build w/ glibc-2.44
+    # If Python.h isn't included first, a const redefinition error now occurs otherwise.
+    (fetchpatch {
+      url = "https://github.com/python/mypy/commit/46acbe85c0e1703ebf2e6d4c699772edcdcf4652.patch";
+      hash = "sha256-KslHiKqinvvXZoxvCnZXOhCm7i8577PbSdNGudCsjZE=";
+    })
+  ];
+
   passthru.updateScript = gitUpdater {
     rev-prefix = "v";
   };