diff --git a/.github/actions/test-package/action.yml b/.github/actions/test-package/action.yml
index 340a7cb6..ef0dbc62 100644
--- a/.github/actions/test-package/action.yml
+++ b/.github/actions/test-package/action.yml
@@ -5,11 +5,6 @@ inputs:
     description: 'Spack spec syntax'
     required: true
     type: string
-  python-version:
-    description: 'Python version'
-    required: false
-    type: string
-    default: '3.13'
 runs:
   using: "composite"
   steps:
@@ -17,28 +12,17 @@ runs:
       shell: sh
       run: |
         apt-get -y update
-        apt-get install -y bzip2 curl file git gzip make patch tar unzip xz-utils
-
-    - uses: actions/setup-python@v6
-      with:
-        python-version: ${{ inputs.python-version }}
+        apt-get install -y file bzip2 ca-certificates g++ gcc gfortran git gzip lsb-release patch python3 tar unzip xz-utils zstd
 
     - name: Set up spack
-      uses: spack/setup-spack@v2
+      uses: spack/setup-spack@v3
       with:
-        ref: develop
-        color: true
-        path: spack
-
-    - name: Install gcc-13 (default)
-      shell: sh
-      if: contains(inputs.spec, 'gcc@13') || (! contains(inputs.spec, 'clang') && ! contains(inputs.spec, 'gcc'))
-      run: apt-get install -y g++ gcc gfortran build-essential
+        spack_ref: develop
 
     - name: Install clang-18
       shell: sh
       if: contains(inputs.spec, 'clang@18')
-      run: apt-get install -y clang-18 gfortran
+      run: apt-get install -y clang-18
 
     - name: Add repos
       shell: spack-bash {0}
@@ -47,12 +31,12 @@ runs:
         spack config get repos
         spack repo list
 
-    - name: add cache
+    - name: Add cache
       shell: spack-bash {0}
       run: |
-        spack mirror add e4s-25.11 https://cache.e4s.io/25.11
-        spack buildcache keys --install --trust
-        spack config add "packages:all:target:[x86_64_v3]"
+         spack mirror add develop https://binaries.spack.io/develop
+         spack config add "packages:all:require:['os=ubuntu24.04','target=x86_64_v3']"
+         spack buildcache keys --install --trust
 
     - name: Compiler find
       shell: spack-bash {0}
@@ -62,14 +46,16 @@ runs:
       shell: spack-bash {0}
       run: spack env create -d ./env
 
-    - name: Add spec
+    - name: Add specs
       shell: spack-bash {0}
       run: spack -e ./env add ${{ inputs.spec }}
 
     - name: Concretize
       shell: spack-bash {0}
-      run: spack -e ./env concretize -j 4
-    
+      run: |
+        spack -e ./env config add concretizer:unify:true
+        spack -e ./env concretize -j 4
+
     - name: Install
       shell: spack-bash {0}
       run: >
@@ -81,5 +67,5 @@ runs:
       if: success() || failure()
       uses: actions/upload-artifact@v4
       with:
-        name: ${{ inputs.spec }}-${{ inputs.python-version }}-log
+        name: ${{ inputs.spec }}-log
         path: log.xml
diff --git a/.github/workflows/spack-matrix.yml b/.github/workflows/spack-matrix.yml
index 0f8c5fc0..1fbbb7b6 100644
--- a/.github/workflows/spack-matrix.yml
+++ b/.github/workflows/spack-matrix.yml
@@ -7,12 +7,13 @@ on:
   pull_request:
   workflow_dispatch:
   schedule:
-    - cron: "0 2 * * MON" # weekly, mondays 2am
+    - cron: "0 2 * * MON" # weekly, Mondays 0200
 
 jobs:
   style-check:
     name: ✨
     runs-on: ubuntu-latest
+
     steps:
       - uses: actions/setup-python@v6
         with:
@@ -20,7 +21,8 @@ jobs:
       - uses: actions/checkout@v5
         with:
           fetch-depth: 2
-      - uses: actions/checkout@v5
+      - name: Fetch Spack CI scripts
+        uses: actions/checkout@v5
         with:
           repository: spack/spack
           ref: develop
@@ -41,15 +43,15 @@ jobs:
       fail-fast: false
       matrix:
         version: ["main", "0.10", "0.9", "0.8"]
-        variant: ["build_type=Developer"]
-        compiler: ["gcc@13", "clang@18"]
+        spec: ["build_type=Developer %gcc@13", "build_type=Developer %clang@18"]
+
     steps:
       - uses: actions/checkout@v5
         with:
           path: spack-fenics
       - uses: ./spack-fenics/.github/actions/test-package
         with:
-          spec: fenics-basix@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
+          spec: fenics-basix@${{ matrix.version }} ${{ matrix.spec }}
 
   fenics-dolfinx:
     needs: style-check
@@ -58,20 +60,39 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        # NOTE: clang sometimes likes stub or Intel MPI. Force MPI implementations.
         version: ["main", "0.10", "0.9", "0.8"]
-        variant: ["build_type=Developer", "partitioners=kahip,parmetis,scotch", "+petsc +slepc +adios2"]
-        compiler: ["gcc@13", "clang@18"]
-        exclude:
-          # kahip does not support clang
-          - variant: "partitioners=kahip,parmetis,scotch"
-            compiler: "clang@18"
+        main_spec: ["build_type=Developer %%c,cxx=clang@18 ^mpich", "build_type=Developer partitioners=kahip,parmetis,scotch +petsc +slepc +adios2 %%gcc@13 ^openmpi"]
+    env:
+      OMPI_ALLOW_RUN_AS_ROOT: 1
+      OMPI_ALLOW_RUN_AS_ROOT_CONFIRM: 1
+      PRTE_MCA_rmaps_default_mapping_policy: :oversubscribe   # Newer OpenMPI
+      OMPI_MCA_rmaps_base_oversubscribe: true                 # Older OpenMPI
+
     steps:
       - uses: actions/checkout@v5
         with:
           path: spack-fenics
       - uses: ./spack-fenics/.github/actions/test-package
         with:
-          spec: fenics-dolfinx@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
+          spec: fenics-dolfinx@${{ matrix.version }} ${{ matrix.main_spec }} py-fenics-ffcx catch2 cmake
+      # FFCx compilation of poisson.py fails in ffcx/codegeneration/C/finite_element.py
+      - name: Run tests (skip 0.8)
+        shell: spack-bash {0}
+        if: ${{ matrix.version != '0.8' }}
+        run: |
+          spack env activate ./env
+          spack load --first catch2 cmake fenics-dolfinx py-fenics-ffcx
+          spack stage fenics-dolfinx@${{ matrix.version }} ${{ matrix.main_spec }}
+          spack cd fenics-dolfinx@${{ matrix.version }} ${{ matrix.main_spec }}
+          spack build-env --dump fenics-dolfinx-build-env.sh fenics-dolfinx
+          source fenics-dolfinx-build-env.sh
+          cmake -B build/test/ -S cpp/test/ -DCMAKE_BUILD_TYPE=Developer
+          cmake --build build/test
+          cd build/test
+          ctest -V --output-on-failure -R unittests_np_1
+          ctest -V --output-on-failure -R unittests_np_3
+
 
   fenics-ufcx:
     needs: style-check
@@ -81,14 +102,15 @@ jobs:
       fail-fast: false
       matrix:
         version: ["main", "0.10", "0.9", "0.8"]
-        compiler: ["gcc@13", "clang@18"]
+        spec: ["%gcc@13"]
+
     steps:
       - uses: actions/checkout@v5
         with:
           path: spack-fenics
       - uses: ./spack-fenics/.github/actions/test-package
         with:
-          spec: fenics-ufcx@${{ matrix.version }} %${{ matrix.compiler }}
+          spec: fenics-ufcx@${{ matrix.version }} ${{ matrix.spec }}
 
   py-fenics-basix:
     needs: style-check
@@ -98,35 +120,35 @@ jobs:
       fail-fast: false
       matrix:
         version: ["main", "0.10", "0.9", "0.8"]
-        variant: ["", "+ufl"]
-        compiler: ["gcc@13", "clang@18"]
+        # Make sure fenics-basix and py-fenics-basix build with same compiler/ABI.
+        spec: ["+ufl %gcc@13 ^fenics-basix%gcc@13", "+ufl %clang@18 ^fenics-basix%clang@18"]
+
     steps:
       - uses: actions/checkout@v5
         with:
           path: spack-fenics
       - uses: ./spack-fenics/.github/actions/test-package
         with:
-          spec: py-fenics-basix@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-      # workaround for https://github.com/spack/spack/issues/29447
-      - name: Run tests (> 0.8)
-        if: ${{ matrix.version != '0.8' && contains(matrix.variant, '+ufl') }}
+          spec: py-fenics-basix@${{ matrix.version }} ${{ matrix.spec }}
+      - name: Run tests
+        if: ${{ matrix.version != '0.8' }}
         shell: spack-bash {0}
         run: |
           spack env activate ./env
-          spack install --add py-pytest py-sympy
-          spack stage py-fenics-basix@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          spack cd py-fenics-basix@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          pytest test/
-      # 0.8 holds one broken test case
-      - name: Run tests (0.8)
-        if: ${{ matrix.version == '0.8' && contains(matrix.variant, '+ufl') }}
+          spack install --add py-pytest py-sympy py-pytest-xdist
+          spack stage py-fenics-basix@${{ matrix.version }} ${{ matrix.spec }}
+          spack cd py-fenics-basix@${{ matrix.version }} ${{ matrix.spec }}
+          python -m pytest -n auto test/
+      # NOTE: 0.8 has test_all_elements_included broken
+      - name: Run tests
+        if: ${{ matrix.version == '0.8' }}
         shell: spack-bash {0}
         run: |
           spack env activate ./env
-          spack install --add py-pytest py-sympy
-          spack stage py-fenics-basix@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          spack cd py-fenics-basix@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          pytest test/ -k "not test_all_elements_included" 
+          spack install --add py-pytest py-sympy py-pytest-xdist
+          spack stage py-fenics-basix@${{ matrix.version }} ${{ matrix.spec }}
+          spack cd py-fenics-basix@${{ matrix.version }} ${{ matrix.spec }}
+          python -m pytest -n auto -k "not test_all_elements_included" test/
 
   py-fenics-dolfinx:
     needs: style-check
@@ -136,37 +158,51 @@ jobs:
       fail-fast: false
       matrix:
         version: ["main", "0.10", "0.9", "0.8"]
-        variant: ["build_type=Developer", "+petsc4py +slepc4py"]
-        compiler: ["gcc@13", "clang@18"]
-        python-version: ["3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.13"]
+        # NOTE: Overspecification of %%clang@18 to fix ABI issues (std::string related?).
+        # NOTE: clang sometimes likes stub or Intel MPI.
+        spec: ["build_type=Developer +petsc4py +slepc4py %%gcc@13 ^petsc+mumps ^fenics-dolfinx+adios2 ^mpich",
+               "build_type=Developer %%clang@18 ^openmpi"]
+        # Test new superlu-dist variant
+        include:
+          - version: "main"
+            spec: "build_type=Developer %%clang@18 ^mpich ^fenics-dolfinx+superlu-dist"
+            python-version: "3.12"
+    env:
+      OMPI_ALLOW_RUN_AS_ROOT: 1
+      OMPI_ALLOW_RUN_AS_ROOT_CONFIRM: 1
+      PRTE_MCA_rmaps_default_mapping_policy: :oversubscribe   # Newer OpenMPI
+      OMPI_MCA_rmaps_base_oversubscribe: true                 # Older OpenMPI
+
     steps:
       - uses: actions/checkout@v5
         with:
           path: spack-fenics
       - uses: ./spack-fenics/.github/actions/test-package
         with:
-          spec: py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          python-version: ${{ matrix.python-version }}
-      # workaround for https://github.com/spack/spack/issues/29447
-      # pytest@8.4 required for collision of [tool.pytest] and [tool.pytest.ini_options] since @9.0 (at least for dolfinx @:0.9)
-      - name: Run tests
-        if: ${{ matrix.version == '0.8' || matrix.version == '0.9'}}
+          spec: py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.spec }} ^python@${{ matrix.python-version }}
+      # pytest@8.4 required for collision of [tool.pytest] and [tool.pytest.ini_options] since @9.0
+      - name: Run tests (0.9)
+        if: ${{ matrix.version == '0.9'}}
         shell: spack-bash {0}
         run: |
           spack env activate ./env
-          spack install --add py-pytest@8.4 py-scipy
-          spack stage py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          spack cd py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          pytest python/test/unit -m "not petsc4py and not adios2" -k "not test_cffi_expression and not test_cube_distance"
-      - name: Run tests
+          spack install --add py-pytest@8.4 py-scipy py-pytest-xdist ^python@${{ matrix.python-version }}
+          spack stage py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.spec }} ^python@${{ matrix.python-version }}
+          spack cd py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.spec }} ^python@${{ matrix.python-version }}
+          python -m pytest -n auto -m "not petsc4py and not adios2" -k "not test_cffi_expression and not test_cube_distance" python/test/unit
+          mpiexec -n 3 python -m pytest -m "not petsc4py and not adios2" -k "not test_cffi_expression and not test_cube_distance" python/test/unit
+      # NOTE: 0.8 tests run very slow - skip?
+      - name: Run tests (not 0.8 and not 0.9)
         if: ${{ matrix.version != '0.8' && matrix.version != '0.9'}}
         shell: spack-bash {0}
         run: |
           spack env activate ./env
-          spack install --add py-pytest@8.4 py-scipy
-          spack stage py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          spack cd py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.variant }} %${{ matrix.compiler }}
-          pytest python/test/unit -m "not petsc4py and not adios2" -k "not test_cffi_expression"
+          spack install --add py-pytest py-scipy py-pytest-xdist ^python@${{ matrix.python-version }}
+          spack stage py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.spec }} ^python@${{ matrix.python-version }}
+          spack cd py-fenics-dolfinx@${{ matrix.version }} ${{ matrix.spec }} ^python@${{ matrix.python-version }}
+          python -m pytest -n auto -m "not petsc4py and not adios2" -k "not test_cffi_expression and not test_symmetry_interior_facet_assembly[mesh1]" python/test/unit
+          mpiexec -n 3 python -m pytest -m "not petsc4py and not adios2" -k "not test_cffi_expression and not test_symmetry_interior_facet_assembly[mesh1]" python/test/unit
 
   py-fenics-ffcx:
     needs: style-check
@@ -176,25 +212,25 @@ jobs:
       fail-fast: false
       matrix:
         version: ["main", "0.10", "0.9", "0.8"]
+
     steps:
       - uses: actions/checkout@v5
         with:
           path: spack-fenics
+      # NOTE: Python built with GCC, otherwise cffi can try for an odd compiler.
       - uses: ./spack-fenics/.github/actions/test-package
         with:
-          spec: py-fenics-ffcx@${{ matrix.version }}
-      # workaround for https://github.com/spack/spack/issues/29447
-      # we do not run numba based tests here due to disk-space constraints
-      # 0.8 broken
+          spec: py-fenics-ffcx@${{ matrix.version }} ^python %%gcc@13
+      # NOTE: ffcx version 0.8 currently broken
       - name: Run tests
         if: ${{ matrix.version != '0.8' }}
         shell: spack-bash {0}
         run: |
           spack env activate ./env
-          spack install --add py-pytest py-sympy
+          spack install --add py-pytest py-sympy py-pytest-xdist
           spack stage py-fenics-ffcx@${{ matrix.version }}
           spack cd py-fenics-ffcx@${{ matrix.version }}
-          pytest test/
+          python -m pytest -n auto test/
 
   py-fenics-ufl:
     needs: style-check
@@ -204,6 +240,7 @@ jobs:
       fail-fast: false
       matrix:
         version: ["main", "2025.2", "2025.1", "2024.2", "2024.1"]
+
     steps:
       - uses: actions/checkout@v5
         with:
@@ -211,12 +248,12 @@ jobs:
       - uses: ./spack-fenics/.github/actions/test-package
         with:
           spec: py-fenics-ufl@${{ matrix.version }}
-      # workaround for https://github.com/spack/spack/issues/29447
+      # NOTE: Reference counting changed in Python 3.14, leading to test failure.
       - name: Run tests
         shell: spack-bash {0}
         run: |
           spack env activate ./env
-          spack install --add py-pytest
+          spack install --add py-pytest py-pytest-xdist
           spack stage py-fenics-ufl@${{ matrix.version }}
           spack cd py-fenics-ufl@${{ matrix.version }}
-          pytest test/
+          python -m pytest -n auto -k "not test_strip_form_arguments_strips_data_refs" test/
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..c081cdb8
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,531 @@
+[project]
+name = "spack"
+description = "The spack package manager"
+requires-python = ">=3.6"
+dependencies = ["clingo", "setuptools"]
+dynamic = ["version"]
+
+[tool.hatch.version]
+path = "repos/spack_repo/builtin/__init__.py"
+
+[project.optional-dependencies]
+dev = [
+  "pip>=21.3",
+  "pytest",
+  "pytest-xdist",
+  "setuptools",
+  "click",
+  "black",
+  "mypy",
+  "isort",
+  "flake8",
+  "vermin",
+]
+ci = ["pytest-cov", "codecov[toml]"]
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+include = [
+  "/repos",
+  "CITATION.cff",
+  "COPYRIGHT",
+  "LICENSE-APACHE",
+  "LICENSE-MIT",
+  "NOTICE",
+  "README.md",
+  "SECURITY.md",
+]
+
+[tool.hatch.envs.default]
+features = ["dev"]
+
+[tool.hatch.envs.ci]
+features = ["dev", "ci"]
+
+[tool.ruff]
+line-length = 99
+extend-include = ["bin/spack"]
+extend-exclude = ["lib/spack/external", "*.pyi"]
+
+# This is the Spack package API. We allow these functions to be imported with
+# from spack.package import *, and we should update this when the package API
+# changes. This also serves to catch the usage of things that are NOT in the
+# package API, so that we can avoid having them in builtin.
+builtins = [
+    # core spack build environment
+    "configure",
+    "cscript",
+    "dso_suffix",
+    "make_jobs",
+    "msbuild",
+    "nmake",
+    "prefix",
+    "python",
+    "python_include",
+    "python_platlib",
+    "python_purelib",
+    "spack_cc",
+    "spack_cxx",
+    "spack_f77",
+    "spack_fc",
+    "static_to_shared_library",
+    # defined in packages or build systems, e.g. -- these can be removed over time
+    "aclocal",
+    "autoconf",
+    "autoheader",
+    "autom4te",
+    "automake",
+    "autoreconf",
+    "autoscan",
+    "autoupdate",
+    "bazel",
+    "cargo",
+    "cmake",
+    "ctest",
+    "gem",
+    "glibtool",
+    "glibtoolize",
+    "gmake",
+    "go",
+    "ifnames",
+    "kentutils_htslib_include_dir",
+    "kentutils_include_dir",
+    "kentutils_lib_dir",
+    "libtool",
+    "libtoolize",
+    "lua",
+    "luarocks",
+    "make",
+    "make",
+    "meson",
+    "msbuild",
+    "ninja",
+    "ninja",
+    "nmake",
+    "octave",
+    "perl",
+    "perl_lib_dir",
+    "pip",
+    "plumed",
+    "pypy",
+    "python",
+    "python_include",
+    "python_platlib",
+    "python_purelib",
+    "qmake",
+    "R",
+    "r_lib_dir",
+    "rake",
+    "ruby",
+    "scons",
+    # v2.0
+    "BaseBuilder",
+    "Builder",
+    "Dict",
+    "EnvironmentModifications",
+    "Executable",
+    "FileFilter",
+    "FileList",
+    "HeaderList",
+    "InstallError",
+    "LibraryList",
+    "List",
+    "MakeExecutable",
+    "NoHeadersError",
+    "NoLibrariesError",
+    "Optional",
+    "PackageBase",
+    "Prefix",
+    "ProcessError",
+    "SkipTest",
+    "Spec",
+    "Version",
+    "all_deptypes",
+    "ancestor",
+    "any_combination_of",
+    "auto_or_any_combination_of",
+    "bash_completion_path",
+    "build_system_flags",
+    "build_system",
+    "cache_extra_test_sources",
+    "can_access",
+    "can_splice",
+    "cd",
+    "change_sed_delimiter",
+    "check_outputs",
+    "conditional",
+    "conflicts",
+    "copy_tree",
+    "copy",
+    "default_args",
+    "depends_on",
+    "determine_number_of_jobs",
+    "disjoint_sets",
+    "env_flags",
+    "env",
+    "extends",
+    "filter_compiler_wrappers",
+    "filter_file",
+    "find_all_headers",
+    "find_first",
+    "find_headers",
+    "find_libraries",
+    "find_required_file",
+    "find_system_libraries",
+    "find",
+    "fish_completion_path",
+    "fix_darwin_install_name",
+    "force_remove",
+    "force_symlink",
+    "get_escaped_text_output",
+    "inject_flags",
+    "install_test_root",
+    "install_tree",
+    "install",
+    "is_exe",
+    "join_path",
+    "keep_modification_time",
+    "library_extensions",
+    "license",
+    "maintainers",
+    "makedirs",
+    "mkdir",
+    "mkdirp",
+    "move",
+    "on_package_attributes",
+    "patch",
+    "provides",
+    "pwd",
+    "redistribute",
+    "register_builder",
+    "remove_directory_contents",
+    "remove_linked_tree",
+    "remove",
+    "removedirs",
+    "rename",
+    "requires",
+    "resource",
+    "rmtree",
+    "run_after",
+    "run_before",
+    "set_executable",
+    "set_install_permissions",
+    "symlink",
+    "test_part",
+    "touch",
+    "tty",
+    "variant",
+    "ver",
+    "version",
+    "when",
+    "which_string",
+    "which",
+    "working_dir",
+    "zsh_completion_path",
+    # v2.1
+    "CompilerError",
+    "SpackError",
+    # v2.2
+    "BuilderWithDefaults",
+    "ClassProperty",
+    "CompilerPropertyDetector",
+    "GenericBuilder",
+    "HKEY",
+    "LC_ID_DYLIB",
+    "LinkTree",
+    "MachO",
+    "ModuleChangePropagator",
+    "Package",
+    "WindowsRegistryView",
+    "apply_macos_rpath_fixups",
+    "classproperty",
+    "compare_output_file",
+    "compare_output",
+    "compile_c_and_execute",
+    "compiler_spec",
+    "create_builder",
+    "dedupe",
+    "delete_needed_from_elf",
+    "delete_rpath",
+    "environment_modifications_for_specs",
+    "execute_install_time_tests",
+    "filter_shebang",
+    "filter_system_paths",
+    "find_all_libraries",
+    "find_compilers",
+    "get_cmake_prefix_path",
+    "get_effective_jobs",
+    "get_elf_compat",
+    "get_path_args_from_module_line",
+    "get_user",
+    "has_shebang",
+    "host_platform",
+    "is_system_path",
+    "join_url",
+    "kernel_version",
+    "libc_from_dynamic_linker",
+    "macos_version",
+    "make_package_test_rpath",
+    "memoized",
+    "microarchitecture_flags_from_target",
+    "microarchitecture_flags",
+    "module_command",
+    "parse_dynamic_linker",
+    "parse_elf",
+    "path_contains_subdirectory",
+    "readlink",
+    "safe_remove",
+    "sbang_install_path",
+    "sbang_shebang_line",
+    "set_env",
+    "shared_library_suffix",
+    "spack_script",
+    "static_library_suffix",
+    "substitute_version_in_url",
+    "windows_sfn",
+]
+
+
+[tool.ruff.format]
+skip-magic-trailing-comma = false
+
+[tool.ruff.lint]
+extend-select = ["I"]
+ignore = ["E731", "E203", "F403", "F811"]
+
+[tool.ruff.lint.isort]
+split-on-trailing-comma = false
+section-order = [
+  "future",
+  "standard-library",
+  "third-party",
+  "llnl",
+  "spack",
+  "first-party",
+  "local-folder",
+]
+
+[tool.ruff.lint.isort.sections]
+spack = ["spack"]
+llnl = ["llnl"]
+
+[tool.ruff.lint.per-file-ignores]
+"var/spack/*/package.py" = ["F403", "F405", "F811", "F821"]
+"*-ci-package.py" = ["F403", "F405", "F821"]
+
+[tool.black]
+line-length = 99
+include = "(repos/spack_repo|tests)/.*\\.pyi?$"
+skip_magic_trailing_comma = true
+
+[tool.isort]
+line_length = 99
+profile = "black"
+sections = [
+  "FUTURE",
+  "STDLIB",
+  "THIRDPARTY",
+  "LLNL",
+  "FIRSTPARTY",
+  "LOCALFOLDER",
+]
+known_first_party = "spack"
+known_llnl = "llnl"
+known_third_party = ["ruamel", "six"]
+src_paths = "lib"
+honor_noqa = true
+
+[tool.mypy]
+files = [
+  "repos/spack_repo/builtin/packages/*/package.py",
+  "repos/spack_repo/builtin/build_systems/*.py",
+]
+mypy_path = ["spack-core/lib/spack", "spack-core/lib/spack/external", "repos/"]
+allow_redefinition = true
+
+# This and a generated import file allows supporting packages
+namespace_packages = true
+
+# To avoid re-factoring all the externals, ignore errors and missing imports
+# globally, then turn back on in spack and spack submodules
+ignore_errors = true
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "spack.*"
+ignore_errors = false
+ignore_missing_imports = false
+
+[[tool.mypy.overrides]]
+module = "spack_repo.*"
+ignore_errors = false
+ignore_missing_imports = false
+# we can't do this here, not a module scope option, in spack style instead
+# disable_error_code = 'no-redef'
+
+[[tool.mypy.overrides]]
+module = "llnl.*"
+ignore_errors = false
+ignore_missing_imports = false
+
+[[tool.mypy.overrides]]
+module = "spack.test.packages"
+ignore_errors = true
+
+# ignore errors in fake import path for packages
+[[tool.mypy.overrides]]
+module = "spack.pkg.*"
+ignore_errors = true
+ignore_missing_imports = true
+
+# Spack imports a number of external packages, and they *may* require Python 3.8 or
+# higher in recent versions. This can cause mypy to fail because we check for 3.7
+# compatibility. We could restrict mypy to run for the oldest supported version (3.7),
+# but that means most developers won't be able to run mypy, which means it'll fail
+# more in CI. Instead, we exclude these imported packages from mypy checking.
+[[tool.mypy.overrides]]
+module = [
+  "IPython",
+  "altgraph",
+  "attr",
+  "boto3",
+  "botocore",
+  "distro",
+  "importlib.metadata",
+  "jinja2",
+  "jsonschema",
+  "macholib",
+  "markupsafe",
+  "numpy",
+  "pkg_resources",
+  "pyristent",
+  "pytest",
+  "ruamel.yaml",
+  "six",
+]
+follow_imports = "skip"
+follow_imports_for_stubs = true
+
+[tool.pyright]
+useLibraryCodeForTypes = true
+reportMissingImports = true
+reportWildcardImportFromLibrary = false
+include = ["lib/spack", "var/spack/repos", "var/spack/test_repos"]
+ignore = ["lib/spack/external"]
+extraPaths = ["lib/spack", "lib/spack/external"]
+
+
+[tool.coverage.run]
+parallel = true
+concurrency = ["multiprocessing"]
+branch = true
+source = ["bin", "lib"]
+data_file = "./tests-coverage/.coverage"
+omit = [
+  "lib/spack/spack/test/*",
+  "lib/spack/docs/*",
+  "lib/spack/external/*",
+  "share/spack/qa/*",
+]
+
+[tool.coverage.report]
+# Regexes for lines to exclude from consideration
+exclude_lines = [
+  # Have to re-enable the standard pragma
+  "pragma: no cover",
+
+  # Don't complain about missing debug-only code:
+  "def __repr__",
+  "if self\\.debug",
+
+  # Don't complain if tests don't hit defensive assertion code:
+  "raise AssertionError",
+  "raise NotImplementedError",
+
+  # Don't complain if non-runnable code isn't run:
+  "if 0:",
+  "if False:",
+  "if __name__ == .__main__.:",
+]
+ignore_errors = true
+
+[tool.coverage.paths]
+source = [
+  ".",
+  "/Users/runner/work/spack/spack",
+  "/System/Volumes/Data/home/runner/work/spack/spack",
+  "D:\\a\\spack\\spack",
+]
+
+[tool.coverage.html]
+directory = "htmlcov"
+
+[tool.vendoring]
+destination = "lib/spack/external/_vendoring"
+requirements = "lib/spack/external/vendor.txt"
+namespace = ""
+
+protected-files = ["__init__.py", "README.rst", "vendor.txt"]
+patches-dir = "lib/spack/external/patches"
+
+[tool.vendoring.transformations]
+substitute = [
+  { match = "typing_extensions", replace = "_vendoring.typing_extensions" },
+  { match = "ruamel.yaml", replace = "_vendoring.ruamel.yaml" },
+  { match = "altgraph", replace = "_vendoring.altgraph" },
+  { match = "macholib", replace = "_vendoring.macholib" },
+  { match = "from six", replace = "from _vendoring.six" },
+  { match = "markupsafe", replace = "_vendoring.markupsafe" },
+  { match = "jinja2", replace = "_vendoring.jinja2" },
+  { match = "pyrsistent", replace = "_vendoring.pyrsistent" },
+  { match = "import attr\n", replace = "import _vendoring.attr\n" },
+  { match = "from attr", replace = "from _vendoring.attr" },
+  { match = "import jsonschema", replace = "import _vendoring.jsonschema" },
+  { match = "from jsonschema", replace = "from _vendoring.jsonschema" },
+]
+drop = [
+  # contains unnecessary scripts
+  "bin/",
+  # interpreter and OS specific msgpack libs
+  "msgpack/*.so",
+  # unneeded parts of setuptools
+  "easy_install.py",
+  "setuptools",
+  "pkg_resources/_vendor/",
+  "pkg_resources/extern/",
+  # trim vendored pygments styles and lexers
+  "pygments/styles/[!_]*.py",
+  "^pygments/lexers/(?!python|__init__|_mapping).*\\.py$",
+  # trim rich's markdown support
+  "rich/markdown.py",
+  # ruamel.yaml installs unneded files
+  "ruamel.*.pth",
+  "pvectorc.*.so",
+  # Trim jsonschema tests
+  "jsonschema/tests",
+  "archspec/json/tests",
+  "archspec/vendor/cpuid/.gitignore",
+  "pyrsistent/__init__.pyi",
+]
+
+[tool.vendoring.typing-stubs]
+_pyrsistent_version = []
+altgraph = []
+archspec = []
+distro = []
+jsonschema = []
+macholib = []
+pyrsistent = []
+ruamel = []
+six = []
+
+[tool.vendoring.license.directories]
+setuptools = "pkg_resources"
+
+[tool.vendoring.license.fallback-urls]
+CacheControl = "https://raw.githubusercontent.com/ionrock/cachecontrol/v0.12.6/LICENSE.txt"
+distlib = "https://bitbucket.org/pypa/distlib/raw/master/LICENSE.txt"
+webencodings = "https://github.com/SimonSapin/python-webencodings/raw/master/LICENSE"
diff --git a/spack_repo/fenics/packages/fenics_basix/package.py b/spack_repo/fenics/packages/fenics_basix/package.py
index 8581f6e1..a85afc31 100644
--- a/spack_repo/fenics/packages/fenics_basix/package.py
+++ b/spack_repo/fenics/packages/fenics_basix/package.py
@@ -18,7 +18,9 @@ class FenicsBasix(CMakePackage):
     license("MIT")
 
     version("main", branch="main", no_cache=True)
-    version("0.10.0.post0", sha256="11a6482fb8d7204fbd77aaf457a9ae3e75db1707b3e30ea2c938eccfee925ea4")
+    version(
+        "0.10.0.post0", sha256="11a6482fb8d7204fbd77aaf457a9ae3e75db1707b3e30ea2c938eccfee925ea4"
+    )
     version("0.10.0", sha256="b93221dac7d3fea8c10e77617f6201036de35d0c5437440b718de69a28c3773f")
     version("0.9.0", sha256="60e96b2393084729b261cb10370f0e44d12735ab3dbd1f15890dec23b9e85329")
     version("0.8.0", sha256="b299af82daf8fa3e4845e17f202491fe71b313bf6ab64c767a5287190b3dd7fe")
diff --git a/spack_repo/fenics/packages/fenics_dolfinx/package.py b/spack_repo/fenics/packages/fenics_dolfinx/package.py
index f63cec81..ee7d4661 100644
--- a/spack_repo/fenics/packages/fenics_dolfinx/package.py
+++ b/spack_repo/fenics/packages/fenics_dolfinx/package.py
@@ -17,7 +17,9 @@ class FenicsDolfinx(CMakePackage):
     license("LGPL-3.0-or-later")
 
     version("main", branch="main", no_cache=True)
-    version("0.10.0.post4", sha256="3f827a88ab52843fbd7a5cc7814ecba165bdec65fd10df05eb031c286e8cd605")
+    version(
+        "0.10.0.post4", sha256="3f827a88ab52843fbd7a5cc7814ecba165bdec65fd10df05eb031c286e8cd605"
+    )
     version(
         "0.10.0.post2", sha256="eae83794fee8141c80c59c03a2f4ac208af2b62c8f36e5d19c93e0d279029f52"
     )
@@ -59,6 +61,7 @@ class FenicsDolfinx(CMakePackage):
     variant("slepc", default=False, description="SLEPc support")
     variant("adios2", default=False, description="ADIOS2 support")
     variant("petsc", default=False, description="PETSc support")
+    variant("superlu-dist", default=False, description="SuperLU_DIST support", when="@main")
 
     conflicts("~petsc", when="+slepc", msg="+slepc requires +petsc")
 
@@ -66,7 +69,8 @@ class FenicsDolfinx(CMakePackage):
     depends_on("cmake@3.19:", when="@:0.8", type="build")
     depends_on("pkgconfig", type="build")
     depends_on("mpi")
-    depends_on("hdf5+mpi")
+    # HDF5Interface.cpp #if H5_VERSION_GE are not precise enough.
+    depends_on("hdf5+mpi@1.12:")
     depends_on("boost@1.70:")
     depends_on("boost@1.70:+timer", when="@:0.9")
     depends_on("pugixml")
@@ -81,6 +85,8 @@ class FenicsDolfinx(CMakePackage):
     depends_on("adios2@2.8.1:", when="@0.9: +adios2")
     depends_on("adios2+mpi", when="+adios2")
 
+    depends_on("superlu-dist", when="+superlu-dist")
+
     for ver in ("main", "0.10", "0.9", "0.8", "0.7", "0.6"):
         depends_on(f"fenics-ufcx@{ver}", when=f"@{ver}")
         depends_on(f"fenics-basix@{ver}", when=f"@{ver}")
@@ -100,4 +106,5 @@ def cmake_args(self):
             self.define("DOLFINX_ENABLE_KAHIP", "partitioners=kahip" in self.spec),
             self.define("DOLFINX_ENABLE_PARMETIS", "partitioners=parmetis" in self.spec),
             self.define("DOLFINX_ENABLE_SCOTCH", "partitioners=scotch" in self.spec),
+            self.define("DOLFINX_ENABLE_SUPERLU_DIST", "superlu-dist" in self.spec),
         ]
diff --git a/spack_repo/fenics/packages/fenics_ufcx/package.py b/spack_repo/fenics/packages/fenics_ufcx/package.py
index c60b26e9..433bc49b 100644
--- a/spack_repo/fenics/packages/fenics_ufcx/package.py
+++ b/spack_repo/fenics/packages/fenics_ufcx/package.py
@@ -17,7 +17,7 @@ class FenicsUfcx(CMakePackage):
     url = "https://github.com/FEniCS/ffcx/archive/v0.4.2.tar.gz"
     maintainers("ma595", "jhale", "garth-wells", "chrisrichardson")
 
-    license("LGPL-3.0-or-later")
+    license("Unlicense")
 
     version("main", branch="main", no_cache=True)
     version("0.10.0", sha256="fa27e2dc68988cbf9aca537eb5a58483f75cc719c1a383713b7f8cca49844ff9")
diff --git a/spack_repo/fenics/packages/py_fenics_basix/package.py b/spack_repo/fenics/packages/py_fenics_basix/package.py
index cafd5b26..df384eb5 100644
--- a/spack_repo/fenics/packages/py_fenics_basix/package.py
+++ b/spack_repo/fenics/packages/py_fenics_basix/package.py
@@ -2,9 +2,10 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-from spack.package import *
 from spack_repo.builtin.build_systems.python import PythonPackage
 
+from spack.package import *
+
 
 class PyFenicsBasix(PythonPackage):
     """Python interface to Basix, a finite element definition and tabulation runtime library"""
@@ -18,30 +19,14 @@ class PyFenicsBasix(PythonPackage):
 
     version("main", branch="main", no_cache=True)
     version(
-        "0.10.0.post0",
-        sha256="11a6482fb8d7204fbd77aaf457a9ae3e75db1707b3e30ea2c938eccfee925ea4",
-    )
-    version(
-        "0.10.0",
-        sha256="b93221dac7d3fea8c10e77617f6201036de35d0c5437440b718de69a28c3773f",
-    )
-    version(
-        "0.9.0",
-        sha256="60e96b2393084729b261cb10370f0e44d12735ab3dbd1f15890dec23b9e85329",
-    )
-    version(
-        "0.8.0",
-        sha256="b299af82daf8fa3e4845e17f202491fe71b313bf6ab64c767a5287190b3dd7fe",
+        "0.10.0.post0", sha256="11a6482fb8d7204fbd77aaf457a9ae3e75db1707b3e30ea2c938eccfee925ea4"
     )
+    version("0.10.0", sha256="b93221dac7d3fea8c10e77617f6201036de35d0c5437440b718de69a28c3773f")
+    version("0.9.0", sha256="60e96b2393084729b261cb10370f0e44d12735ab3dbd1f15890dec23b9e85329")
+    version("0.8.0", sha256="b299af82daf8fa3e4845e17f202491fe71b313bf6ab64c767a5287190b3dd7fe")
     with default_args(deprecated=True):
-        version(
-            "0.7.0",
-            sha256="9bee81b396ee452eec8d9735f278cb44cb6994c6bc30aec8ed9bb4b12d83fa7f",
-        )
-        version(
-            "0.6.0",
-            sha256="687ae53153c98facac4080dcdc7081701db1dcea8c5e7ae3feb72aec17f83304",
-        )
+        version("0.7.0", sha256="9bee81b396ee452eec8d9735f278cb44cb6994c6bc30aec8ed9bb4b12d83fa7f")
+        version("0.6.0", sha256="687ae53153c98facac4080dcdc7081701db1dcea8c5e7ae3feb72aec17f83304")
 
     # CMake build type
     variant(
diff --git a/spack_repo/fenics/packages/py_fenics_dolfinx/package.py b/spack_repo/fenics/packages/py_fenics_dolfinx/package.py
index 53c2eb83..50a11956 100644
--- a/spack_repo/fenics/packages/py_fenics_dolfinx/package.py
+++ b/spack_repo/fenics/packages/py_fenics_dolfinx/package.py
@@ -2,9 +2,10 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-from spack.package import *
 from spack_repo.builtin.build_systems.python import PythonPackage
 
+from spack.package import *
+
 
 class PyFenicsDolfinx(PythonPackage):
     """Python interface to the next generation FEniCS problem solving
@@ -19,26 +20,13 @@ class PyFenicsDolfinx(PythonPackage):
 
     version("main", branch="main", no_cache=True)
     version(
-        "0.10.0.post4",
-        sha256="3f827a88ab52843fbd7a5cc7814ecba165bdec65fd10df05eb031c286e8cd605",
-    )
-    version(
-        "0.9.0",
-        sha256="b266c74360c2590c5745d74768c04568c965b44739becca4cd6b5aa58cdbbbd1",
-    )
-    version(
-        "0.8.0",
-        sha256="acf3104d9ecc0380677a6faf69eabfafc58d0cce43f7777e1307b95701c7cad9",
+        "0.10.0.post4", sha256="3f827a88ab52843fbd7a5cc7814ecba165bdec65fd10df05eb031c286e8cd605"
     )
+    version("0.9.0", sha256="b266c74360c2590c5745d74768c04568c965b44739becca4cd6b5aa58cdbbbd1")
+    version("0.8.0", sha256="acf3104d9ecc0380677a6faf69eabfafc58d0cce43f7777e1307b95701c7cad9")
     with default_args(deprecated=True):
-        version(
-            "0.7.2",
-            sha256="7d9ce1338ce66580593b376327f23ac464a4ce89ef63c105efc1a38e5eae5c0b",
-        )
-        version(
-            "0.6.0",
-            sha256="eb8ac2bb2f032b0d393977993e1ab6b4101a84d54023a67206e3eac1a8d79b80",
-        )
+        version("0.7.2", sha256="7d9ce1338ce66580593b376327f23ac464a4ce89ef63c105efc1a38e5eae5c0b")
+        version("0.6.0", sha256="eb8ac2bb2f032b0d393977993e1ab6b4101a84d54023a67206e3eac1a8d79b80")
 
     # CMake build type
     variant(
@@ -89,11 +77,7 @@ class PyFenicsDolfinx(PythonPackage):
     depends_on("py-numpy@1.21:", type=("build", "run"))
     depends_on("py-mpi4py", type=("build", "run"))
 
-    conflicts(
-        "~petsc4py",
-        when="@:0.8",
-        msg="+petsc4py is required for versions 0.8 and lower",
-    )
+    conflicts("~petsc4py", when="@:0.8", msg="+petsc4py is required for versions 0.8 and lower")
     conflicts("~petsc4py", when="+slepc4py", msg="+slepc4py requires +petsc4py")
     with when("+petsc4py"):
         depends_on("fenics-dolfinx +petsc")
diff --git a/spack_repo/fenics/packages/py_fenics_ffcx/package.py b/spack_repo/fenics/packages/py_fenics_ffcx/package.py
index 4d49f5b0..de101992 100644
--- a/spack_repo/fenics/packages/py_fenics_ffcx/package.py
+++ b/spack_repo/fenics/packages/py_fenics_ffcx/package.py
@@ -18,7 +18,9 @@ class PyFenicsFfcx(PythonPackage):
     license("LGPL-3.0-or-later")
 
     version("main", branch="main", no_cache=True)
-    version("0.10.1.post0", sha256="91e15e2586390d0a0b0e9993d63b47b7ae9657e5141fc30271291ea1a2d55d5e")
+    version(
+        "0.10.1.post0", sha256="91e15e2586390d0a0b0e9993d63b47b7ae9657e5141fc30271291ea1a2d55d5e"
+    )
     version("0.9.0", sha256="afa517272a3d2249f513cb711c50b77cf8368dd0b8f5ea4b759142229204a448")
     version("0.8.0", sha256="8a854782dbd119ec1c23c4522a2134d5281e7f1bd2f37d64489f75da055282e3")
     with default_args(deprecated=True):