From c1601a2afa8b504a7e5ec693f8d54eba59f2d613 Mon Sep 17 00:00:00 2001
From: qbisi <qbisicwate@gmail.com>
Date: Fri, 26 Sep 2025 19:16:15 +0800
Subject: [PATCH] scotch: install *metis.h to subdirectory

SCOTCH has compatibility headers/libraries for the
MeTiS/ParMeTiS interface. However, the header files
"metis.h" and "parmetis.h" might cause conflict with
exsiting metis/parmetis packages. Hence move them to
subdirectory.
---
 pkgs/by-name/mu/mumps/package.nix  | 18 ++++++++----------
 pkgs/by-name/sc/scotch/package.nix | 12 ++++++++++++
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/pkgs/by-name/mu/mumps/package.nix b/pkgs/by-name/mu/mumps/package.nix
index f490a3ffcd01..d536e153cd37 100644
--- a/pkgs/by-name/mu/mumps/package.nix
+++ b/pkgs/by-name/mu/mumps/package.nix
@@ -108,16 +108,14 @@ stdenv.mkDerivation (finalAttrs: {
   ++ lib.optional mpiSupport mpi
   ++ lib.optional stdenv.hostPlatform.isDarwin fixDarwinDylibNames;
 
-  # Parmetis should be placed before scotch to avoid conflict of header file "parmetis.h"
-  buildInputs =
-    lib.optional withParmetis parmetis
-    ++ lib.optional mpiSupport scalapack
-    ++ [
-      blas
-      lapack
-      metis
-      scotch'
-    ];
+  buildInputs = [
+    blas
+    lapack
+    metis
+    scotch'
+  ]
+  ++ lib.optional mpiSupport scalapack
+  ++ lib.optional withParmetis parmetis;
 
   doInstallCheck = true;
 
diff --git a/pkgs/by-name/sc/scotch/package.nix b/pkgs/by-name/sc/scotch/package.nix
index 5e586bab1b66..9fafe1d1da77 100644
--- a/pkgs/by-name/sc/scotch/package.nix
+++ b/pkgs/by-name/sc/scotch/package.nix
@@ -35,6 +35,10 @@ stdenv.mkDerivation (finalAttrs: {
   cmakeFlags = [
     (lib.cmakeBool "BUILD_SHARED_LIBS" (!stdenv.hostPlatform.isStatic))
     (lib.cmakeBool "BUILD_PTSCOTCH" withPtScotch)
+    # Prefix Scotch version of MeTiS routines
+    (lib.cmakeBool "SCOTCH_METIS_PREFIX" true)
+    # building tests is broken with SCOTCH_METIS_PREFIX enabled in 7.0.9
+    (lib.cmakeBool "ENABLE_TESTS" false)
   ];
 
   nativeBuildInputs = [
@@ -63,6 +67,14 @@ stdenv.mkDerivation (finalAttrs: {
     };
   };
 
+  # SCOTCH provide compatibility with Metis/Parmetis interface.
+  # We install the metis compatible headers to subdirectory to
+  # avoid conflict with metis/parmetis.
+  postFixup = ''
+    mkdir -p $dev/include/scotch
+    mv $dev/include/{*metis,metisf}.h $dev/include/scotch
+  '';
+
   meta = {
     description = "Graph and mesh/hypergraph partitioning, graph clustering, and sparse matrix ordering";
     longDescription = ''