From a240aec21332a94574c9fef9c4b08e2d5f948c1d Mon Sep 17 00:00:00 2001
From: Connor Ward <c.ward20@imperial.ac.uk>
Date: Wed, 11 Dec 2024 14:26:21 +0000
Subject: [PATCH] Use a pip-installed libsupermesh

---
 firedrake/supermeshing.py |  6 ++++--
 pyproject.toml            |  2 ++
 setup.py                  | 21 +++++++++++++--------
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/firedrake/supermeshing.py b/firedrake/supermeshing.py
index a1ce2cde17..14da853c55 100644
--- a/firedrake/supermeshing.py
+++ b/firedrake/supermeshing.py
@@ -1,7 +1,8 @@
 # Code for projections and other fun stuff involving supermeshes.
 import firedrake
 import ctypes
-import sys
+import pathlib
+import libsupermesh
 from firedrake.cython.supermeshimpl import assemble_mixed_mass_matrix as ammm, intersection_finder
 from firedrake.mg.utils import get_level
 from firedrake.petsc import PETSc
@@ -428,7 +429,8 @@ def likely(cell_A):
         "complex_mode": 1 if complex_mode else 0
     }
 
-    dirs = get_petsc_dir() + (sys.prefix, )
+    libsupermesh_dir = pathlib.Path(libsupermesh.__path__._path[0]).absolute()
+    dirs = get_petsc_dir() + (libsupermesh_dir,)
     includes = ["-I%s/include" % d for d in dirs]
     libs = ["-L%s/lib" % d for d in dirs]
     libs = libs + ["-Wl,-rpath,%s/lib" % d for d in dirs] + ["-lpetsc", "-lsupermesh"]
diff --git a/pyproject.toml b/pyproject.toml
index fe15d8e7c1..f849865b38 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,6 +38,7 @@ dependencies = [
   "fenics-fiat @ git+https://github.com/firedrakeproject/fiat.git",
   "pyadjoint-ad @ git+https://github.com/dolfin-adjoint/pyadjoint.git",
   "loopy @ git+https://github.com/firedrakeproject/loopy.git@main",
+  "libsupermesh @ git+https://github.com/firedrakeproject/libsupermesh.git@connorjward/pip-install2",
 ]
 classifiers = [
   "Development Status :: 5 - Production/Stable",
@@ -98,6 +99,7 @@ requires = [
   "mpi4py; python_version < '3.13'",
   "petsc4py",
   "rtree>=1.2",
+  "libsupermesh @ git+https://github.com/firedrakeproject/libsupermesh.git@connorjward/pip-install2",
 ]
 build-backend = "setuptools.build_meta"
 
diff --git a/setup.py b/setup.py
index cf970c1712..b30abd4b49 100644
--- a/setup.py
+++ b/setup.py
@@ -6,6 +6,7 @@
 import pybind11
 import petsc4py
 import rtree
+import libsupermesh
 import pkgconfig
 from dataclasses import dataclass, field
 from setuptools import setup, find_packages, Extension
@@ -145,6 +146,9 @@ def __getitem__(self, key):
 # In the next 2 linkages we are using `site.getsitepackages()[0]`, which isn't
 # guaranteed to be the correct place we could also use "$ORIGIN/../../lib_dir",
 # but that definitely doesn't work with editable installs.
+# This is necessary because Python build isolation means that the compile-time
+# library dirs (in the isolated build env) are different to the run-time
+# library dirs (in the venv).
 
 # libspatialindex
 # example:
@@ -159,15 +163,16 @@ def __getitem__(self, key):
 
 # libsupermesh
 # example:
-# gcc -I/supermesh/include
-# gcc /supermesh/supermesh.cpython-311-x86_64-linux-gnu.so \
+# gcc -Ipath/to/libsupermesh/include
+# gcc path/to/libsupermesh/libsupermesh.cpython-311-x86_64-linux-gnu.so \
 #    -lsupermesh \
-#    -Wl,-rpath,$ORIGIN/../../supermesh
-supermesh_ = ExternalDependency(
-    include_dirs=[f"{sys.prefix}/include"],
-    library_dirs=[f"{sys.prefix}/lib"],
+#    -Wl,-rpath,$ORIGIN/../../libsupermesh
+libsupermesh_dir = Path(libsupermesh.__path__._path[0]).absolute()
+libsupermesh_ = ExternalDependency(
+    include_dirs=[str(libsupermesh_dir.joinpath("include"))],
+    library_dirs=[str(libsupermesh_dir.joinpath("lib"))],
+    runtime_library_dirs=[os.path.join(site.getsitepackages()[0], "libsupermesh", "lib")],
     libraries=["supermesh"],
-    runtime_library_dirs=[f"{sys.prefix}/lib"],
 )
 
 # The following extensions need to be linked accordingly:
@@ -221,7 +226,7 @@ def extensions():
         name="firedrake.cython.supermeshimpl",
         language="c",
         sources=[os.path.join("firedrake", "cython", "supermeshimpl.pyx")],
-        **(petsc_ + numpy_ + supermesh_)
+        **(petsc_ + numpy_ + libsupermesh_)
     ))
     # pyop2/sparsity.pyx: petsc, numpy,
     cython_list.append(Extension(