feat: support pypa build (#521)

* feat: support pypa build

fix: update `cibuildwheel.linux.troubleshoot` to know about build

Workaround issue with PyPy venv module by installing build[virtualenv]

fix: test_dependency_constraints_file when using build

fix: test/test_pep518.py

fix: use `strtobool` to parse `CIBW_PYPA_BUILD`

fix: update `cibuildwheel.linux.troubleshoot` to know about `python -m pip wheel`

test: use `build_mode` in `test/test_dependency_versions.py` tests

* refactor: use build-backend instead

* Apply suggestions from code review

Co-authored-by: Joe Rickerby <joerick@mac.com>

* refactor: use literal types for build_frontend

* refactor(tests): build_mode -> build_frontend_env

* Update test/test_before_build.py

Co-authored-by: Joe Rickerby <joerick@mac.com>

test/conftest.py

@@ -1,7 +1,9 @@
+from typing import Dict
+
 import pytest
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser) -> None:
     parser.addoption(
         "--run-emulation", action="store_true", default=False, help="run emulation tests"
     )
@@ -11,7 +13,7 @@ def pytest_configure(config):
     config.addinivalue_line("markers", "emulation: mark test requiring qemu binfmt_misc to run")
 
 
-def pytest_collection_modifyitems(config, items):
+def pytest_collection_modifyitems(config, items) -> None:
     if config.getoption("--run-emulation"):
         # --run-emulation given in cli: do not skip emulation tests
         return
@@ -19,3 +21,10 @@ def pytest_collection_modifyitems(config, items):
     for item in items:
         if "emulation" in item.keywords:
             item.add_marker(skip_emulation)
+
+
+@pytest.fixture(
+    params=[{"CIBW_BUILD_FRONTEND": "pip"}, {"CIBW_BUILD_FRONTEND": "build"}], ids=["pip", "build"]
+)
+def build_frontend_env(request) -> Dict[str, str]:
+    return request.param  # type: ignore

test/test_0_basic.py

@@ -18,12 +18,12 @@ basic_project = test_projects.new_c_project(
 )
 
 
-def test(tmp_path):
+def test(tmp_path, build_frontend_env):
     project_dir = tmp_path / "project"
     basic_project.generate(project_dir)
 
     # build the wheels
-    actual_wheels = utils.cibuildwheel_run(project_dir)
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env=build_frontend_env)
 
     # check that the expected wheels are produced
     expected_wheels = utils.expected_wheels("spam", "0.1.0")

test/test_before_build.py

@@ -25,8 +25,13 @@ project_with_before_build_asserts = test_projects.new_c_project(
             stored_executable = f.read()
         print('stored_executable', stored_executable)
         print('sys.executable', sys.executable)
+
         # windows/mac are case insensitive
-        assert os.path.realpath(stored_executable).lower() == os.path.realpath(sys.executable).lower()
+        stored_path = os.path.realpath(stored_executable).lower()
+        current_path = os.path.realpath(sys.executable).lower()
+
+        # TODO: This is not valid in an virtual environment
+        assert stored_path == current_path, '{0} != {1}'.format(stored_path, current_path)
         """
     )
 )

test/test_dependency_versions.py

@@ -48,7 +48,7 @@ def get_versions_from_constraint_file(constraint_file):
 
 
 @pytest.mark.parametrize("python_version", ["3.6", "3.8", "3.9"])
-def test_pinned_versions(tmp_path, python_version):
+def test_pinned_versions(tmp_path, python_version, build_frontend_env):
     if utils.platform == "linux":
         pytest.skip("linux doesn't pin individual tool versions, it pins manylinux images instead")
 
@@ -85,6 +85,7 @@ def test_pinned_versions(tmp_path, python_version):
         add_env={
             "CIBW_BUILD": build_pattern,
             "CIBW_ENVIRONMENT": cibw_environment_option,
+            **build_frontend_env,
         },
     )
 
@@ -107,7 +108,7 @@ def test_pinned_versions(tmp_path, python_version):
     assert set(actual_wheels) == set(expected_wheels)
 
 
-def test_dependency_constraints_file(tmp_path):
+def test_dependency_constraints_file(tmp_path, build_frontend_env):
     if utils.platform == "linux":
         pytest.skip("linux doesn't pin individual tool versions, it pins manylinux images instead")
 
@@ -118,7 +119,7 @@ def test_dependency_constraints_file(tmp_path):
         "pip": "20.0.2",
         "setuptools": "53.0.0",
         "wheel": "0.34.2",
-        "virtualenv": "20.0.10",
+        "virtualenv": "20.0.35",
     }
 
     constraints_file = tmp_path / "constraints.txt"
@@ -129,6 +130,7 @@ def test_dependency_constraints_file(tmp_path):
             setuptools=={setuptools}
             wheel=={wheel}
             virtualenv=={virtualenv}
+            importlib-metadata<3,>=0.12; python_version < "3.8"
             """.format(
                 **tool_versions
             )
@@ -149,6 +151,7 @@ def test_dependency_constraints_file(tmp_path):
         add_env={
             "CIBW_ENVIRONMENT": cibw_environment_option,
             "CIBW_DEPENDENCY_VERSIONS": str(constraints_file),
+            **build_frontend_env,
         },
     )
 

test/test_pep518.py

@@ -1,4 +1,3 @@
-import os
 import textwrap
 
 from . import test_projects, utils
@@ -33,13 +32,13 @@ build-backend = "setuptools.build_meta"
 """
 
 
-def test_pep518(tmp_path):
+def test_pep518(tmp_path, build_frontend_env):
 
     project_dir = tmp_path / "project"
     basic_project.generate(project_dir)
 
     # build the wheels
-    actual_wheels = utils.cibuildwheel_run(project_dir)
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env=build_frontend_env)
 
     # check that the expected wheels are produced
     expected_wheels = utils.expected_wheels("spam", "0.1.0")
@@ -50,4 +49,12 @@ def test_pep518(tmp_path):
     assert not (project_dir / "42").exists()
     assert not (project_dir / "4.1.2").exists()
 
-    assert len(os.listdir(project_dir)) == len(basic_project.files)
+    # pypa/build creates a "build" folder & a "*.egg-info" folder for the wheel being built,
+    # this should be harmless so remove them
+    contents = [
+        item
+        for item in project_dir.iterdir()
+        if item.name != "build" and not item.name.endswith(".egg-info")
+    ]
+
+    assert len(contents) == len(basic_project.files)

test/test_troubleshooting.py

@@ -16,7 +16,7 @@ raise Exception('this build will fail')
 """
 
 
-def test_failed_project_with_so_files(tmp_path, capfd):
+def test_failed_project_with_so_files(tmp_path, capfd, build_frontend_env):
     if utils.platform != "linux":
         pytest.skip("this test is only relevant to the linux build")
 
@@ -24,7 +24,7 @@ def test_failed_project_with_so_files(tmp_path, capfd):
     so_file_project.generate(project_dir)
 
     with pytest.raises(subprocess.CalledProcessError):
-        utils.cibuildwheel_run(project_dir)
+        utils.cibuildwheel_run(project_dir, add_env=build_frontend_env)
 
     captured = capfd.readouterr()
     print("out", captured.out)