fix: Support older cmake

.github/workflows/ci.yml

@@ -34,7 +34,9 @@ jobs:
           pipx run nox -s pylint
 
   checks:
-    name: Check Python ${{ matrix.python-version }} on ${{ matrix.runs-on }}
+    name:
+      🐍 ${{ matrix.python-version }} on ${{ matrix.runs-on }} ${{ matrix.cmake
+      }}
     runs-on: ${{ matrix.runs-on }}
     needs: [pre-commit]
     strategy:
@@ -46,6 +48,12 @@ jobs:
         include:
           - python-version: pypy-3.10
             runs-on: ubuntu-latest
+          - python-version: "3.9"
+            runs-on: ubuntu-latest
+            cmake: "3.20.x"
+          - python-version: "3.10"
+            runs-on: ubuntu-latest
+            cmake: "3.15.x"
 
     steps:
       - uses: actions/checkout@v4
@@ -57,6 +65,14 @@ jobs:
           python-version: ${{ matrix.python-version }}
           allow-prereleases: true
 
+      - uses: jwlawson/actions-setup-cmake@v2
+        if: matrix.cmake != ''
+        with:
+          cmake-version: ${{ matrix.cmake }}
+
+      - run: pipx install ninja
+        if: matrix.cmake == '3.15.x'
+
       - uses: yezz123/setup-uv@v4
 
       - name: Install package

src/cython_cmake/cmake/UseCython.cmake

@@ -64,6 +64,9 @@
 # limitations under the License.
 #=============================================================================
 
+if(CMAKE_VERSION VERSION_LESS "3.7")
+  message(SEND_ERROR "CMake 3.7 required for DEPFILE")
+endif()
 
 function(Cython_compile_pyx)
   set(_options )
@@ -116,7 +119,11 @@ function(Cython_compile_pyx)
   set(generated_files)
 
   foreach(_source_file IN LISTS _source_files)
-    cmake_path(GET _source_file STEM _name)
+
+    # Can use cmake_path for CMake 3.20+
+    # cmake_path(GET _source_file STEM _name)
+    get_filename_component(_name "${_source_file}" NAME_WE)
+
     set(generated_file "${CMAKE_CURRENT_BINARY_DIR}/${_name}.${_language_extension}")
     set_source_files_properties(${generated_file} PROPERTIES GENERATED TRUE)
 

tests/conftest.py

@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+import importlib.metadata
+import shutil
+import subprocess
+
+
+def _get_program(name: str) -> str:
+    res = shutil.which(name)
+    if res is None:
+        return f"No {name} executable found on PATH"
+    result = subprocess.run(
+        [res, "--version"], check=True, text=True, capture_output=True
+    )
+    version = result.stdout.splitlines()[0]
+    return f"{res}: {version}"
+
+
+def pytest_report_header() -> str:
+    interesting_packages = {
+        "cmake",
+        "ninja",
+        "packaging",
+        "pip",
+        "scikit-build-core",
+    }
+    valid = []
+    for package in interesting_packages:
+        try:
+            version = importlib.metadata.version(package)
+        except ModuleNotFoundError:
+            continue
+        valid.append(f"{package}=={version}")
+    reqs = " ".join(sorted(valid))
+    pkg_line = f"installed packages of interest: {reqs}"
+    prog_lines = [_get_program(n) for n in ("cmake3", "cmake", "ninja")]
+
+    return "\n".join([pkg_line, *prog_lines])