From ae6b0ae161663d3c911d6dcabf61643146586fcd Mon Sep 17 00:00:00 2001
From: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
Date: Fri, 3 Oct 2025 14:14:20 +0200
Subject: [PATCH] Move MPICH to pkgs/mpich and set as default
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Reviewed-by: Aleix Boné <abonerib@bsc.es>
---
 overlay.nix            |  2 ++
 pkgs/mpich/default.nix | 78 +++++++++++++-----------------------------
 pkgs/overlay.nix       | 30 ----------------
 3 files changed, 25 insertions(+), 85 deletions(-)

diff --git a/overlay.nix b/overlay.nix
index 4831c555..08f51901 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -20,6 +20,8 @@ let
     jemallocNanos6 = callPackage ./pkgs/nanos6/jemalloc.nix { };
     lmbench = callPackage ./pkgs/lmbench/default.nix { };
     mcxx = callPackage ./pkgs/mcxx/default.nix { };
+    mpi = final.mpich; # Set MPICH as default
+    mpich = callPackage ./pkgs/mpich/default.nix { mpich = prev.mpich; };
     nanos6 = callPackage ./pkgs/nanos6/default.nix { };
     nanos6Debug = final.nanos6.override { enableDebug = true; };
     nixtools = callPackage ./pkgs/nixtools/default.nix { };
diff --git a/pkgs/mpich/default.nix b/pkgs/mpich/default.nix
index 36bee859..4b5307ab 100644
--- a/pkgs/mpich/default.nix
+++ b/pkgs/mpich/default.nix
@@ -1,68 +1,36 @@
 {
   stdenv
 , lib
-, fetchurl
-, perl
-, gfortran
-, openssh
-, hwloc
 , libfabric
-, enableDebug ? false
+, mpich
+, pmix
+, gfortran
+, symlinkJoin
 }:
 
-with lib;
-
-stdenv.mkDerivation  rec {
-  pname = "mpich";
-  version = "3.3.2";
-
-  src = fetchurl {
-    url = "https://www.mpich.org/static/downloads/${version}/mpich-${version}.tar.gz";
-    sha256 = "1farz5zfx4cd0c3a0wb9pgfypzw0xxql1j1294z1sxslga1ziyjb";
+let
+  # pmix comes with the libraries in .out and headers in .dev
+  pmixAll = symlinkJoin {
+    name = "pmix-all";
+    paths = [ pmix.dev pmix.out ];
   };
-
+in mpich.overrideAttrs (old: {
+  buildInput = old.buildInputs ++ [
+    libfabric
+    pmixAll
+  ];
   configureFlags = [
     "--enable-shared"
     "--enable-sharedlib"
+    "--with-pm=no"
     "--with-device=ch4:ofi"
+    "--with-pmi=pmix"
+    "--with-pmix=${pmixAll}"
     "--with-libfabric=${libfabric}"
-  ]
-  ++ optional enableDebug "--enable-g=dbg,log";
-
-  enableParallelBuilding = true;
-
-  buildInputs = [ perl gfortran openssh hwloc libfabric ];
+    "--enable-g=log"
+  ] ++ lib.optionals (lib.versionAtLeast gfortran.version "10") [
+    "FFLAGS=-fallow-argument-mismatch" # https://github.com/pmodels/mpich/issues/4300
+    "FCFLAGS=-fallow-argument-mismatch"
+  ];
   hardeningDisable = [ "all" ];
-
-  # doCheck = true; # Fails
-
-  preFixup = ''
-    # Ensure the default compilers are the ones mpich was built with
-    sed -i 's:CC="gcc":CC=${stdenv.cc}/bin/gcc:' $out/bin/mpicc
-    sed -i 's:CXX="g++":CXX=${stdenv.cc}/bin/g++:' $out/bin/mpicxx
-    sed -i 's:FC="gfortran":FC=${gfortran}/bin/gfortran:' $out/bin/mpifort
-  ''
-  + lib.optionalString (!stdenv.isDarwin) ''
-    # /tmp/nix-build... ends up in the RPATH, fix it manually
-    for entry in $out/bin/mpichversion $out/bin/mpivars; do
-      echo "fix rpath: $entry"
-      patchelf --set-rpath "$out/lib" $entry
-    done
-    '';
-
-  meta = with lib; {
-    description = "Implementation of the Message Passing Interface (MPI) standard";
-
-    longDescription = ''
-      MPICH is a high-performance and widely portable implementation of
-      the Message Passing Interface (MPI) standard (MPI-1, MPI-2 and MPI-3).
-    '';
-    homepage = "http://www.mpich.org";
-    license = {
-      url = "https://github.com/pmodels/mpich/blob/v${version}/COPYRIGHT";
-      fullName = "MPICH license (permissive)";
-    };
-    maintainers = [ ];
-    platforms = platforms.linux ++ platforms.darwin;
-  };
-}
+})
diff --git a/pkgs/overlay.nix b/pkgs/overlay.nix
index 4198cd30..d3be38d6 100644
--- a/pkgs/overlay.nix
+++ b/pkgs/overlay.nix
@@ -1,35 +1,5 @@
 final: prev:
 {
-  # Set MPICH as default
-  mpi = final.mpich;
-
-  # Configure the network for MPICH
-  mpich = with final; let
-    # pmix comes with the libraries in .out and headers in .dev
-    pmixAll = symlinkJoin {
-      name = "pmix-all";
-      paths = [ pmix.dev pmix.out ];
-    };
-  in prev.mpich.overrideAttrs (old: {
-    buildInput = old.buildInputs ++ [
-      libfabric
-      pmixAll
-    ];
-    configureFlags = [
-      "--enable-shared"
-      "--enable-sharedlib"
-      "--with-pm=no"
-      "--with-device=ch4:ofi"
-      "--with-pmi=pmix"
-      "--with-pmix=${pmixAll}"
-      "--with-libfabric=${libfabric}"
-      "--enable-g=log"
-    ] ++ lib.optionals (lib.versionAtLeast gfortran.version "10") [
-      "FFLAGS=-fallow-argument-mismatch" # https://github.com/pmodels/mpich/issues/4300
-      "FCFLAGS=-fallow-argument-mismatch"
-    ];
-  });
-
   slurm = prev.slurm.overrideAttrs (old: {
     patches = (old.patches or []) ++ [
       # See https://bugs.schedmd.com/show_bug.cgi?id=19324