From 0744c89bb06489b17f1ed190eb26eed435268da9 Mon Sep 17 00:00:00 2001
From: stubbiali <subbiali@phys.ethz.ch>
Date: Tue, 9 Jan 2024 15:11:50 +0100
Subject: [PATCH] Add in-tree build backend.

---
 MANIFEST.in       |  1 +
 _build/backend.py | 25 +++++++++++++++++++++++++
 pyproject.toml    |  5 +++--
 3 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 _build/backend.py

diff --git a/MANIFEST.in b/MANIFEST.in
index e3497466e..545dec44b 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -22,3 +22,4 @@ include *.py
 include *.release
 include *.sh
 include LICENSE
+include _build/*.py
diff --git a/_build/backend.py b/_build/backend.py
new file mode 100644
index 000000000..cefffa925
--- /dev/null
+++ b/_build/backend.py
@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+import os
+from setuptools.build_meta import *
+import subprocess
+
+
+def netcdf_has_parallel_support():
+    netcdf4_dir = os.environ.get("NETCDF4_DIR")
+    ncconfig = os.path.join(netcdf4_dir, "bin", "nc-config") if netcdf4_dir else "nc-config"
+    process = subprocess.run([ncconfig, "--has-parallel4"], capture_output=True)
+    out = process.stdout.decode("utf-8").rstrip()
+    return out == "yes"
+
+
+def get_requires_for_build_editable(config_settings=None):
+    return ["mpi4py>=3.1"] if netcdf_has_parallel_support() else []
+
+
+def get_requires_for_build_wheel(config_settings=None):
+    return ["mpi4py>=3.1"] if netcdf_has_parallel_support() else []
+
+
+def get_requires_for_build_sdist(config_settings=None):
+    return ["mpi4py>=3.1"] if netcdf_has_parallel_support() else []
+
diff --git a/pyproject.toml b/pyproject.toml
index cb3d98717..f0467a670 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,11 +1,12 @@
 [build-system]
 requires = [
     "Cython>=0.29",
-    "mpi4py>=3.1",
     "oldest-supported-numpy",
     "setuptools>=61",
+    "wheel"
 ]
-build-backend = "setuptools.build_meta"
+build-backend = "backend"
+backend-path = ["_build"]
 
 [project]
 name = "netCDF4"