Support projects without setup.py (pyproject.toml and setup.cfg are also valid)

cibuildwheel/__main__.py

@@ -161,7 +161,7 @@ def main() -> None:
     # This needs to be passed on to the docker container in linux.py
     os.environ['CIBUILDWHEEL'] = '1'
 
-    if not os.path.exists(os.path.join(package_dir, 'setup.py')):
+    if not detect_setup_pyproject_existence(package_dir):
         print('cibuildwheel: Could not find setup.py at root of package', file=sys.stderr)
         exit(2)
 
@@ -309,5 +309,16 @@ def detect_warnings(platform: str, build_options: BuildOptions) -> List[str]:
     return warnings
 
 
+def detect_setup_pyproject_existence(package_dir: str) -> bool:
+    exists = False
+    if os.path.exists(os.path.join(package_dir, 'setup.py')):
+        exists = True
+
+    if os.path.exists(os.path.join(package_dir, 'pyproject.toml')):
+        exists = True
+
+    return exists
+
+
 if __name__ == '__main__':
     main()

test/test_poetry_project.py

@@ -0,0 +1,53 @@
+from . import test_projects
+from . import utils
+
+pyproject_package_file = """
+[tool.poetry]
+name = "dummy_package"
+version = "0.1.0"
+description = "dummy"
+authors = ["cibuildwheel poetry test"]
+classifiers=[
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Natural Language :: English",
+    "Programming Language :: Python :: 2.7",
+    "Programming Language :: Python :: 3.6",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+]
+license = "MIT"
+[tool.poetry.dependencies]
+python = ">=2.7"
+[tool.poetry.dev-dependencies]
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
+"""
+
+poetry_dummy_project = test_projects.TestProject()
+poetry_dummy_project.files["dummy_package/__init__.py"] = ""
+poetry_dummy_project.files["pyproject.toml"] = pyproject_package_file
+
+
+def test_poetry_package(tmp_path):
+
+    # GIVEN a project that only has pyproject.toml
+    # managed by poetry
+    project_dir = tmp_path / "project"
+    poetry_dummy_project.generate(project_dir)
+
+    # Poetry is installed during wheels built by pip
+    # however, one of poetry deps require cryptography
+    # which fails to build in outdated pip versions
+    # more info: https://github.com/pyca/cryptography/issues/5101
+    skip_outdated_pip_images_env = {'CIBW_SKIP': 'cp27-* *-win32 *-manylinux_i686'}
+
+    # WHEN we attempt to build wheels for multiple platforms
+    # for dummy_package package
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env=skip_outdated_pip_images_env)
+
+    # THEN we should have a dummy_package wheel with version 0.1.0
+    expected_wheels = utils.expected_wheels("dummy_package", "0.1.0")
+    assert set(actual_wheels) == set(expected_wheels)