Add Python script to build wheels using cibuildwheel (#10096)

The contents are extracted from the current GitHub action definition:
https://github.com/mypyc/mypy_mypyc-wheels/blob/master/.github/workflows/build.yml

This is a fairly direct translation of the existing behavior. The
behavior should be identical to the current workflow.

The idea is to make this easier to maintain and easier to test
locally.

This should also make it easier to fix #10074.

misc/build_wheel.py

@@ -0,0 +1,131 @@
+"""Script to build compiled binary wheels that can be uploaded to PyPI.
+
+The main GitHub workflow where this script is used:
+https://github.com/mypyc/mypy_mypyc-wheels/blob/master/.github/workflows/build.yml
+
+This uses cibuildwheel (https://github.com/joerick/cibuildwheel) to
+build the wheels.
+
+Usage:
+
+  build_wheel_ci.py --python-version <python-version> \
+                    --output-dir <dir>
+
+Wheels for the given Python version will be created in the given directory.
+Python version is in form "39".
+
+This works on macOS, Windows and Linux.
+
+You can test locally by using --extra-opts. macOS example:
+
+  mypy/misc/build_wheel_ci.py --python-version 39 --output-dir out --extra-opts="--platform macos"
+
+Other supported values for platform: linux, windows
+"""
+
+import argparse
+import os
+import subprocess
+import sys
+from typing import Dict
+
+# Clang package we use on Linux
+LLVM_URL = 'https://github.com/mypyc/mypy_mypyc-wheels/releases/download/llvm/llvm-centos-5.tar.gz'
+
+# Mypy repository root
+ROOT_DIR = os.path.dirname(os.path.dirname(__file__))
+
+
+def create_environ(python_version: str) -> Dict[str, str]:
+    """Set up environment variables for cibuildwheel."""
+    env = os.environ.copy()
+
+    env['CIBW_BUILD'] = "cp{}-*".format(python_version)
+
+    # Don't build 32-bit wheels
+    env['CIBW_SKIP'] = "*-manylinux_i686 *-win32"
+
+    env['CIBW_BUILD_VERBOSITY'] = '1'
+
+    # mypy's isolated builds don't specify the requirements mypyc needs, so install
+    # requirements and don't use isolated builds. we need to use build-requirements.txt
+    # with recent mypy commits to get stub packages needed for compilation.
+    #
+    # TODO: remove use of mypy-requirements.txt once we no longer need to support
+    #       building pre modular typeshed releases
+    env['CIBW_BEFORE_BUILD'] = """
+      pip install -r {package}/mypy-requirements.txt &&
+      (pip install -r {package}/build-requirements.txt || true)
+    """.replace('\n', ' ')
+
+    # download a copy of clang to use to compile on linux. this was probably built in 2018,
+    # speeds up compilation 2x
+    env['CIBW_BEFORE_BUILD_LINUX'] = """
+      (cd / && curl -L %s | tar xzf -) &&
+      pip install -r {package}/mypy-requirements.txt &&
+      (pip install -r {package}/build-requirements.txt || true)
+    """.replace('\n', ' ') % LLVM_URL
+
+    # the double negative is counterintuitive, https://github.com/pypa/pip/issues/5735
+    env['CIBW_ENVIRONMENT'] = 'MYPY_USE_MYPYC=1 MYPYC_OPT_LEVEL=3 PIP_NO_BUILD_ISOLATION=no'
+    env['CIBW_ENVIRONMENT_LINUX'] = (
+        'MYPY_USE_MYPYC=1 MYPYC_OPT_LEVEL=3 PIP_NO_BUILD_ISOLATION=no ' +
+        'CC=/opt/llvm/bin/clang'
+    )
+    env['CIBW_ENVIRONMENT_WINDOWS'] = (
+        'MYPY_USE_MYPYC=1 MYPYC_OPT_LEVEL=2 PIP_NO_BUILD_ISOLATION=no'
+    )
+
+    # lxml is slow to build wheels for new releases, so allow installing reqs to fail
+    # if we failed to install lxml, we'll skip tests, but allow the build to succeed
+    env['CIBW_BEFORE_TEST'] = (
+        'pip install -r {project}/mypy/test-requirements.txt || true'
+    )
+
+    # pytest looks for configuration files in the parent directories of where the tests live.
+    # since we are trying to run the tests from their installed location, we copy those into
+    # the venv. Ew ew ew.
+    env['CIBW_TEST_COMMAND'] = """
+      ( ! pip list | grep lxml ) || (
+      DIR=$(python -c 'import mypy, os; dn = os.path.dirname; print(dn(dn(mypy.__path__[0])))')
+      && TEST_DIR=$(python -c 'import mypy.test; print(mypy.test.__path__[0])')
+      && cp '{project}/mypy/pytest.ini' '{project}/mypy/conftest.py' $DIR
+      && MYPY_TEST_PREFIX='{project}/mypy' pytest $TEST_DIR
+      )
+    """.replace('\n', ' ')
+
+    # i ran into some flaky tests on windows, so only run testcheck. it looks like we
+    # previously didn't run any tests on windows wheels, so this is a net win.
+    env['CIBW_TEST_COMMAND_WINDOWS'] = """
+      bash -c "
+      ( ! pip list | grep lxml ) || (
+      DIR=$(python -c 'import mypy, os; dn = os.path.dirname; print(dn(dn(mypy.__path__[0])))')
+      && TEST_DIR=$(python -c 'import mypy.test; print(mypy.test.__path__[0])')
+      && cp '{project}/mypy/pytest.ini' '{project}/mypy/conftest.py' $DIR
+      && MYPY_TEST_PREFIX='{project}/mypy' pytest $TEST_DIR/testcheck.py
+      )
+      "
+    """.replace('\n', ' ')
+    return env
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--python-version', required=True, metavar='XY',
+                        help='Python version (e.g. 38 or 39)')
+    parser.add_argument('--output-dir', required=True, metavar='DIR',
+                        help='Output directory for created wheels')
+    parser.add_argument('--extra-opts', default='', metavar='OPTIONS',
+                        help='Extra options passed to cibuildwheel verbatim')
+    args = parser.parse_args()
+    python_version = args.python_version
+    output_dir = args.output_dir
+    extra_opts = args.extra_opts
+    environ = create_environ(python_version)
+    script = 'python -m cibuildwheel {} --output-dir {} {}'.format(extra_opts, output_dir,
+                                                                   ROOT_DIR)
+    subprocess.check_call(script, shell=True, env=environ)
+
+
+if __name__ == '__main__':
+    main()