Merge pull request #854 from henryiii/henryiii/feat/override

.pre-commit-config.yaml

@@ -59,6 +59,7 @@ repos:
       - tomli
       - types-certifi
       - types-click
+      - types-dataclasses
       - types-jinja2
       - types-pyyaml
       - types-requests

cibuildwheel/__main__.py

@@ -2,7 +2,6 @@ import argparse
 import os
 import sys
 import textwrap
-from pathlib import Path
 from typing import List, Set, Union
 
 import cibuildwheel
@@ -11,14 +10,9 @@ import cibuildwheel.macos
 import cibuildwheel.util
 import cibuildwheel.windows
 from cibuildwheel.architecture import Architecture, allowed_architectures_check
-from cibuildwheel.options import compute_options
+from cibuildwheel.options import CommandLineArguments, Options, compute_options
 from cibuildwheel.typing import PLATFORMS, PlatformName, assert_never
-from cibuildwheel.util import (
+from cibuildwheel.util import BuildSelector, Unbuffered, detect_ci_provider
-    BuildOptions,
-    BuildSelector,
-    Unbuffered,
-    detect_ci_provider,
-)
 
 
 def main() -> None:
@@ -104,7 +98,7 @@ def main() -> None:
         help="Enable pre-release Python versions if available.",
     )
 
-    args = parser.parse_args()
+    args = parser.parse_args(namespace=CommandLineArguments())
 
     if args.platform != "auto":
         platform = args.platform
@@ -141,19 +135,21 @@ def main() -> None:
         print(f"cibuildwheel: Unsupported platform: {platform}", file=sys.stderr)
         sys.exit(2)
 
-    package_dir = Path(args.package_dir)
+    options = compute_options(platform=platform, command_line_arguments=args)
-    output_dir = Path(
-        args.output_dir
-        if args.output_dir is not None
-        else os.environ.get("CIBW_OUTPUT_DIR", "wheelhouse")
-    )
 
-    build_options = compute_options(
+    package_dir = options.globals.package_dir
-        platform, package_dir, output_dir, args.config_file, args.archs, args.prerelease_pythons
+    package_files = {"setup.py", "setup.cfg", "pyproject.toml"}
-    )
+
+    if not any(package_dir.joinpath(name).exists() for name in package_files):
+        names = ", ".join(sorted(package_files, reverse=True))
+        msg = f"cibuildwheel: Could not find any of {{{names}}} at root of package"
+        print(msg, file=sys.stderr)
+        sys.exit(2)
 
     identifiers = get_build_identifiers(
-        platform, build_options.build_selector, build_options.architectures
+        platform=platform,
+        build_selector=options.globals.build_selector,
+        architectures=options.globals.architectures,
     )
 
     if args.print_build_identifiers:
@@ -168,22 +164,25 @@ def main() -> None:
     # Python is buffering by default when running on the CI platforms, giving problems interleaving subprocess call output with unflushed calls to 'print'
     sys.stdout = Unbuffered(sys.stdout)  # type: ignore[no-untyped-call,assignment]
 
-    print_preamble(platform, build_options)
+    print_preamble(platform=platform, options=options, identifiers=identifiers)
 
     try:
-        allowed_architectures_check(platform, build_options.architectures)
+        options.check_for_invalid_configuration(identifiers)
+        allowed_architectures_check(platform, options.globals.architectures)
     except ValueError as err:
         print("cibuildwheel:", *err.args, file=sys.stderr)
         sys.exit(4)
 
     if not identifiers:
         print(
-            f"cibuildwheel: No build identifiers selected: {build_options.build_selector}",
+            f"cibuildwheel: No build identifiers selected: {options.globals.build_selector}",
             file=sys.stderr,
         )
         if not args.allow_empty:
             sys.exit(3)
 
+    output_dir = options.globals.output_dir
+
     if not output_dir.exists():
         output_dir.mkdir(parents=True)
 
@@ -191,16 +190,16 @@ def main() -> None:
         "\n{n} wheels produced in {m:.0f} minutes:", output_dir
     ):
         if platform == "linux":
-            cibuildwheel.linux.build(build_options)
+            cibuildwheel.linux.build(options)
         elif platform == "windows":
-            cibuildwheel.windows.build(build_options)
+            cibuildwheel.windows.build(options)
         elif platform == "macos":
-            cibuildwheel.macos.build(build_options)
+            cibuildwheel.macos.build(options)
         else:
             assert_never(platform)
 
 
-def print_preamble(platform: str, build_options: BuildOptions) -> None:
+def print_preamble(platform: str, options: Options, identifiers: List[str]) -> None:
     print(
         textwrap.dedent(
             """
@@ -216,9 +215,9 @@ def print_preamble(platform: str, build_options: BuildOptions) -> None:
 
     print("Build options:")
     print(f"  platform: {platform!r}")
-    print(textwrap.indent(str(build_options), "  "))
+    print(textwrap.indent(options.summary(identifiers), "  "))
 
-    warnings = detect_warnings(platform, build_options)
+    warnings = detect_warnings(platform=platform, options=options, identifiers=identifiers)
     if warnings:
         print("\nWarnings:")
         for warning in warnings:
@@ -254,14 +253,14 @@ def get_build_identifiers(
     return [config.identifier for config in python_configurations]
 
 
-def detect_warnings(platform: str, build_options: BuildOptions) -> List[str]:
+def detect_warnings(platform: str, options: Options, identifiers: List[str]) -> List[str]:
     warnings = []
 
     # warn about deprecated {python} and {pip}
     for option_name in ["test_command", "before_build"]:
-        option_value = getattr(build_options, option_name)
+        option_values = [getattr(options.build_options(i), option_name) for i in identifiers]
 
-        if option_value and ("{python}" in option_value or "{pip}" in option_value):
+        if any(o and ("{python}" in o or "{pip}" in o) for o in option_values):
             # Reminder: in an f-string, double braces means literal single brace
             msg = (
                 f"{option_name}: '{{python}}' and '{{pip}}' are no longer needed, "

cibuildwheel/docker_container.py

@@ -17,7 +17,7 @@ class DockerContainer:
     An object that represents a running Docker container.
 
     Intended for use as a context manager e.g.
-    `with DockerContainer('ubuntu') as docker:`
+    `with DockerContainer(docker_image = 'ubuntu') as docker:`
 
     A bash shell is running in the remote container. When `call()` is invoked,
     the command is relayed to the remote shell, and the results are streamed
@@ -31,7 +31,7 @@ class DockerContainer:
     bash_stdout: IO[bytes]
 
     def __init__(
-        self, docker_image: str, simulate_32_bit: bool = False, cwd: Optional[PathOrStr] = None
+        self, *, docker_image: str, simulate_32_bit: bool = False, cwd: Optional[PathOrStr] = None
     ):
         if not docker_image:
             raise ValueError("Must have a non-empty docker image to run.")

cibuildwheel/environment.py

@@ -1,3 +1,4 @@
+import dataclasses
 from typing import Dict, List, Mapping, Optional
 
 import bashlex
@@ -60,10 +61,15 @@ class EnvironmentAssignment:
     def __repr__(self) -> str:
         return f"{self.name}={self.value}"
 
+    def __eq__(self, other: object) -> bool:
+        if isinstance(other, EnvironmentAssignment):
+            return self.name == other.name and self.value == other.value
+        return False
 
+
+@dataclasses.dataclass
 class ParsedEnvironment:
-    def __init__(self, assignments: List[EnvironmentAssignment]):
+    assignments: List[EnvironmentAssignment]
-        self.assignments = assignments
 
     def as_dictionary(
         self,
@@ -82,7 +88,7 @@ class ParsedEnvironment:
         return [a.as_shell_assignment() for a in self.assignments]
 
     def __repr__(self) -> str:
-        return f"ParsedEnvironment({[repr(a) for a in self.assignments]!r})"
+        return f"{self.__class__.__name__}({[repr(a) for a in self.assignments]!r})"
 
 
 def parse_environment(env_string: str) -> ParsedEnvironment:

cibuildwheel/linux.py

@@ -1,15 +1,16 @@
 import subprocess
 import sys
 import textwrap
+from collections import OrderedDict
 from pathlib import Path, PurePath
 from typing import Iterator, List, NamedTuple, Set
 
 from .architecture import Architecture
 from .docker_container import DockerContainer
 from .logger import log
+from .options import Options
 from .typing import PathOrStr, assert_never
 from .util import (
-    BuildOptions,
     BuildSelector,
     NonPlatformWheelError,
     get_build_verbosity_extra_flags,
@@ -53,48 +54,55 @@ def get_python_configurations(
     ]
 
 
-def get_build_steps(
+def docker_image_for_python_configuration(config: PythonConfiguration, options: Options) -> str:
-    options: BuildOptions, python_configurations: List[PythonConfiguration]
+    build_options = options.build_options(config.identifier)
-) -> Iterator[BuildStep]:
+    # e.g
-    platforms = [
+    # identifier is 'cp310-manylinux_x86_64'
-        ("cp", "manylinux_x86_64", "x86_64"),
+    # platform_tag is 'manylinux_x86_64'
-        ("cp", "manylinux_i686", "i686"),
+    # platform_arch is 'x86_64'
-        ("cp", "manylinux_aarch64", "aarch64"),
+    _, platform_tag = config.identifier.split("-", 1)
-        ("cp", "manylinux_ppc64le", "ppc64le"),
+    _, platform_arch = platform_tag.split("_", 1)
-        ("cp", "manylinux_s390x", "s390x"),
-        ("pp", "manylinux_x86_64", "pypy_x86_64"),
-        ("pp", "manylinux_aarch64", "pypy_aarch64"),
-        ("pp", "manylinux_i686", "pypy_i686"),
-        ("cp", "musllinux_x86_64", "x86_64"),
-        ("cp", "musllinux_i686", "i686"),
-        ("cp", "musllinux_aarch64", "aarch64"),
-        ("cp", "musllinux_ppc64le", "ppc64le"),
-        ("cp", "musllinux_s390x", "s390x"),
-    ]
 
-    for implementation, platform_tag, platform_arch in platforms:
+    assert build_options.manylinux_images is not None
-        assert options.manylinux_images is not None
+    assert build_options.musllinux_images is not None
-        assert options.musllinux_images is not None
 
-        docker_image = (
+    return (
-            options.manylinux_images[platform_arch]
+        build_options.manylinux_images[platform_arch]
         if platform_tag.startswith("manylinux")
-            else options.musllinux_images[platform_arch]
+        else build_options.musllinux_images[platform_arch]
     )
 
-        platform_configs = [
-            c
-            for c in python_configurations
-            if c.identifier.startswith(implementation) and c.identifier.endswith(platform_tag)
-        ]
-        if not platform_configs:
-            continue
 
-        yield BuildStep(platform_configs, platform_tag, docker_image)
+def get_build_steps(
+    options: Options, python_configurations: List[PythonConfiguration]
+) -> Iterator[BuildStep]:
+    """
+    Groups PythonConfigurations into BuildSteps. Each BuildStep represents a
+    separate Docker container.
+    """
+    steps: OrderedDict[tuple, BuildStep] = OrderedDict()  # type: ignore[type-arg]
+
+    for config in python_configurations:
+        _, platform_tag = config.identifier.split("-", 1)
+
+        before_all = options.build_options(config.identifier).before_all
+        docker_image = docker_image_for_python_configuration(config, options)
+
+        step_key = (platform_tag, docker_image, before_all)
+
+        if step_key in steps:
+            steps[step_key].platform_configs.append(config)
+        else:
+            steps[step_key] = BuildStep(
+                platform_configs=[config], platform_tag=platform_tag, docker_image=docker_image
+            )
+
+    yield from steps.values()
 
 
 def build_on_docker(
-    options: BuildOptions,
+    *,
+    options: Options,
     platform_configs: List[PythonConfiguration],
     docker: DockerContainer,
     container_project_path: PurePath,
@@ -105,16 +113,21 @@ def build_on_docker(
     log.step("Copying project into Docker...")
     docker.copy_into(Path.cwd(), container_project_path)
 
-    if options.before_all:
+    before_all_options_identifier = platform_configs[0].identifier
+    before_all_options = options.build_options(before_all_options_identifier)
+
+    if before_all_options.before_all:
         log.step("Running before_all...")
 
         env = docker.get_environment()
         env["PATH"] = f'/opt/python/cp38-cp38/bin:{env["PATH"]}'
         env["PIP_DISABLE_PIP_VERSION_CHECK"] = "1"
-        env = options.environment.as_dictionary(env, executor=docker.environment_executor)
+        env = before_all_options.environment.as_dictionary(
+            env, executor=docker.environment_executor
+        )
 
         before_all_prepared = prepare_command(
-            options.before_all,
+            before_all_options.before_all,
             project=container_project_path,
             package=container_package_dir,
         )
@@ -122,11 +135,14 @@ def build_on_docker(
 
     for config in platform_configs:
         log.build_start(config.identifier)
+        build_options = options.build_options(config.identifier)
 
         dependency_constraint_flags: List[PathOrStr] = []
 
-        if options.dependency_constraints:
+        if build_options.dependency_constraints:
-            constraints_file = options.dependency_constraints.get_for_python_version(config.version)
+            constraints_file = build_options.dependency_constraints.get_for_python_version(
+                config.version
+            )
             container_constraints_file = PurePath("/constraints.txt")
 
             docker.copy_into(constraints_file, container_constraints_file)
@@ -140,7 +156,7 @@ def build_on_docker(
         python_bin = config.path / "bin"
         env["PATH"] = f'{python_bin}:{env["PATH"]}'
 
-        env = options.environment.as_dictionary(env, executor=docker.environment_executor)
+        env = build_options.environment.as_dictionary(env, executor=docker.environment_executor)
 
         # check config python is still on PATH
         which_python = docker.call(["which", "python"], env=env, capture_output=True).strip()
@@ -159,10 +175,10 @@ def build_on_docker(
             )
             sys.exit(1)
 
-        if options.before_build:
+        if build_options.before_build:
             log.step("Running before_build...")
             before_build_prepared = prepare_command(
-                options.before_build,
+                build_options.before_build,
                 project=container_project_path,
                 package=container_package_dir,
             )
@@ -175,9 +191,9 @@ def build_on_docker(
         docker.call(["rm", "-rf", built_wheel_dir])
         docker.call(["mkdir", "-p", built_wheel_dir])
 
-        verbosity_flags = get_build_verbosity_extra_flags(options.build_verbosity)
+        verbosity_flags = get_build_verbosity_extra_flags(build_options.build_verbosity)
 
-        if options.build_frontend == "pip":
+        if build_options.build_frontend == "pip":
             docker.call(
                 [
                     "python",
@@ -191,7 +207,7 @@ def build_on_docker(
                 ],
                 env=env,
             )
-        elif options.build_frontend == "build":
+        elif build_options.build_frontend == "build":
             config_setting = " ".join(verbosity_flags)
             docker.call(
                 [
@@ -206,7 +222,7 @@ def build_on_docker(
                 env=env,
             )
         else:
-            assert_never(options.build_frontend)
+            assert_never(build_options.build_frontend)
 
         built_wheel = docker.glob(built_wheel_dir, "*.whl")[0]
 
@@ -217,10 +233,10 @@ def build_on_docker(
         if built_wheel.name.endswith("none-any.whl"):
             raise NonPlatformWheelError()
 
-        if options.repair_command:
+        if build_options.repair_command:
             log.step("Repairing wheel...")
             repair_command_prepared = prepare_command(
-                options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir
+                build_options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir
             )
             docker.call(["sh", "-c", repair_command_prepared], env=env)
         else:
@@ -228,7 +244,7 @@ def build_on_docker(
 
         repaired_wheels = docker.glob(repaired_wheel_dir, "*.whl")
 
-        if options.test_command and options.test_selector(config.identifier):
+        if build_options.test_command and build_options.test_selector(config.identifier):
             log.step("Testing wheel...")
 
             # set up a virtual environment to install and test from, to make sure
@@ -241,9 +257,9 @@ def build_on_docker(
             virtualenv_env = env.copy()
             virtualenv_env["PATH"] = f"{venv_dir / 'bin'}:{virtualenv_env['PATH']}"
 
-            if options.before_test:
+            if build_options.before_test:
                 before_test_prepared = prepare_command(
-                    options.before_test,
+                    build_options.before_test,
                     project=container_project_path,
                     package=container_package_dir,
                 )
@@ -257,17 +273,17 @@ def build_on_docker(
             # Let's just pick the first one.
             wheel_to_test = repaired_wheels[0]
             docker.call(
-                ["pip", "install", str(wheel_to_test) + options.test_extras],
+                ["pip", "install", str(wheel_to_test) + build_options.test_extras],
                 env=virtualenv_env,
             )
 
             # Install any requirements to run the tests
-            if options.test_requires:
+            if build_options.test_requires:
-                docker.call(["pip", "install", *options.test_requires], env=virtualenv_env)
+                docker.call(["pip", "install", *build_options.test_requires], env=virtualenv_env)
 
             # Run the tests from a different directory
             test_command_prepared = prepare_command(
-                options.test_command,
+                build_options.test_command,
                 project=container_project_path,
                 package=container_package_dir,
             )
@@ -284,11 +300,11 @@ def build_on_docker(
 
     log.step("Copying wheels back to host...")
     # copy the output back into the host
-    docker.copy_out(container_output_dir, options.output_dir)
+    docker.copy_out(container_output_dir, options.globals.output_dir)
     log.step_end()
 
 
-def build(options: BuildOptions) -> None:
+def build(options: Options) -> None:
     try:
         # check docker is installed
         subprocess.run(["docker", "--version"], check=True, stdout=subprocess.DEVNULL)
@@ -301,12 +317,12 @@ def build(options: BuildOptions) -> None:
         )
         sys.exit(2)
 
-    assert options.manylinux_images is not None
+    python_configurations = get_python_configurations(
-    assert options.musllinux_images is not None
+        options.globals.build_selector, options.globals.architectures
-    python_configurations = get_python_configurations(options.build_selector, options.architectures)
+    )
 
     cwd = Path.cwd()
-    abs_package_dir = options.package_dir.resolve()
+    abs_package_dir = options.globals.package_dir.resolve()
     if cwd != abs_package_dir and cwd not in abs_package_dir.parents:
         raise Exception("package_dir must be inside the working directory")
 
@@ -315,20 +331,23 @@ def build(options: BuildOptions) -> None:
 
     for build_step in get_build_steps(options, python_configurations):
         try:
-            log.step(f"Starting Docker image {build_step.docker_image}...")
+            ids_to_build = [x.identifier for x in build_step.platform_configs]
+            log.step(
+                f"Starting Docker image {build_step.docker_image} for {', '.join(ids_to_build)}..."
+            )
 
             with DockerContainer(
-                build_step.docker_image,
+                docker_image=build_step.docker_image,
                 simulate_32_bit=build_step.platform_tag.endswith("i686"),
                 cwd=container_project_path,
             ) as docker:
 
                 build_on_docker(
-                    options,
+                    options=options,
-                    build_step.platform_configs,
+                    platform_configs=build_step.platform_configs,
-                    docker,
+                    docker=docker,
-                    container_project_path,
+                    container_project_path=container_project_path,
-                    container_package_dir,
+                    container_package_dir=container_package_dir,
                 )
 
         except subprocess.CalledProcessError as error:
@@ -346,16 +365,18 @@ def _matches_prepared_command(error_cmd: List[str], command_template: str) -> bo
     return error_cmd[2].startswith(command_prefix)
 
 
-def troubleshoot(options: BuildOptions, error: Exception) -> None:
+def troubleshoot(options: Options, error: Exception) -> None:
 
     if isinstance(error, subprocess.CalledProcessError) and (
         error.cmd[0:4] == ["python", "-m", "pip", "wheel"]
         or error.cmd[0:3] == ["python", "-m", "build"]
-        or _matches_prepared_command(error.cmd, options.repair_command)
+        or _matches_prepared_command(
+            error.cmd, options.build_options(None).repair_command
+        )  # TODO allow matching of overrides too?
     ):
-        # the wheel build step failed
+        # the wheel build step or the repair step failed
         print("Checking for common errors...")
-        so_files = list(options.package_dir.glob("**/*.so"))
+        so_files = list(options.globals.package_dir.glob("**/*.so"))
 
         if so_files:
             print(

cibuildwheel/macos.py

@@ -12,10 +12,10 @@ from typing import Any, Dict, List, NamedTuple, Optional, Sequence, Set, Tuple,
 from .architecture import Architecture
 from .environment import ParsedEnvironment
 from .logger import log
+from .options import Options
 from .typing import Literal, PathOrStr, assert_never
 from .util import (
     BuildFrontend,
-    BuildOptions,
     BuildSelector,
     NonPlatformWheelError,
     download,
@@ -322,49 +322,53 @@ def setup_python(
     return env
 
 
-def build(options: BuildOptions) -> None:
+def build(options: Options) -> None:
     temp_dir = Path(tempfile.mkdtemp(prefix="cibuildwheel"))
     built_wheel_dir = temp_dir / "built_wheel"
     repaired_wheel_dir = temp_dir / "repaired_wheel"
 
+    python_configurations = get_python_configurations(
+        options.globals.build_selector, options.globals.architectures
+    )
+
     try:
-        if options.before_all:
+        before_all_options_identifier = python_configurations[0].identifier
+        before_all_options = options.build_options(before_all_options_identifier)
+
+        if before_all_options.before_all:
             log.step("Running before_all...")
-            env = options.environment.as_dictionary(prev_environment=os.environ)
+            env = before_all_options.environment.as_dictionary(prev_environment=os.environ)
             env.setdefault("MACOSX_DEPLOYMENT_TARGET", "10.9")
             before_all_prepared = prepare_command(
-                options.before_all, project=".", package=options.package_dir
+                before_all_options.before_all, project=".", package=before_all_options.package_dir
             )
             call([before_all_prepared], shell=True, env=env)
 
-        python_configurations = get_python_configurations(
-            options.build_selector, options.architectures
-        )
-
         for config in python_configurations:
+            build_options = options.build_options(config.identifier)
             log.build_start(config.identifier)
 
             config_is_arm64 = config.identifier.endswith("arm64")
             config_is_universal2 = config.identifier.endswith("universal2")
 
             dependency_constraint_flags: Sequence[PathOrStr] = []
-            if options.dependency_constraints:
+            if build_options.dependency_constraints:
                 dependency_constraint_flags = [
                     "-c",
-                    options.dependency_constraints.get_for_python_version(config.version),
+                    build_options.dependency_constraints.get_for_python_version(config.version),
                 ]
 
             env = setup_python(
                 config,
                 dependency_constraint_flags,
-                options.environment,
+                build_options.environment,
-                options.build_frontend,
+                build_options.build_frontend,
             )
 
-            if options.before_build:
+            if build_options.before_build:
                 log.step("Running before_build...")
                 before_build_prepared = prepare_command(
-                    options.before_build, project=".", package=options.package_dir
+                    build_options.before_build, project=".", package=build_options.package_dir
                 )
                 call(before_build_prepared, env=env, shell=True)
 
@@ -373,9 +377,9 @@ def build(options: BuildOptions) -> None:
                 shutil.rmtree(built_wheel_dir)
             built_wheel_dir.mkdir(parents=True)
 
-            verbosity_flags = get_build_verbosity_extra_flags(options.build_verbosity)
+            verbosity_flags = get_build_verbosity_extra_flags(build_options.build_verbosity)
 
-            if options.build_frontend == "pip":
+            if build_options.build_frontend == "pip":
                 # Path.resolve() is needed. Without it pip wheel may try to fetch package from pypi.org
                 # see https://github.com/pypa/cibuildwheel/pull/369
                 call(
@@ -384,18 +388,20 @@ def build(options: BuildOptions) -> None:
                         "-m",
                         "pip",
                         "wheel",
-                        options.package_dir.resolve(),
+                        build_options.package_dir.resolve(),
                         f"--wheel-dir={built_wheel_dir}",
                         "--no-deps",
                         *verbosity_flags,
                     ],
                     env=env,
                 )
-            elif options.build_frontend == "build":
+            elif build_options.build_frontend == "build":
                 config_setting = " ".join(verbosity_flags)
                 build_env = env.copy()
-                if options.dependency_constraints:
+                if build_options.dependency_constraints:
-                    constr = options.dependency_constraints.get_for_python_version(config.version)
+                    constr = build_options.dependency_constraints.get_for_python_version(
+                        config.version
+                    )
                     build_env["PIP_CONSTRAINT"] = constr.as_uri()
                 build_env["VIRTUALENV_PIP"] = get_pip_version(env)
                 call(
@@ -403,7 +409,7 @@ def build(options: BuildOptions) -> None:
                         "python",
                         "-m",
                         "build",
-                        options.package_dir,
+                        build_options.package_dir,
                         "--wheel",
                         f"--outdir={built_wheel_dir}",
                         f"--config-setting={config_setting}",
@@ -411,7 +417,7 @@ def build(options: BuildOptions) -> None:
                     env=build_env,
                 )
             else:
-                assert_never(options.build_frontend)
+                assert_never(build_options.build_frontend)
 
             built_wheel = next(built_wheel_dir.glob("*.whl"))
 
@@ -422,7 +428,7 @@ def build(options: BuildOptions) -> None:
             if built_wheel.name.endswith("none-any.whl"):
                 raise NonPlatformWheelError()
 
-            if options.repair_command:
+            if build_options.repair_command:
                 log.step("Repairing wheel...")
 
                 if config_is_universal2:
@@ -433,7 +439,7 @@ def build(options: BuildOptions) -> None:
                     delocate_archs = "x86_64"
 
                 repair_command_prepared = prepare_command(
-                    options.repair_command,
+                    build_options.repair_command,
                     wheel=built_wheel,
                     dest_dir=repaired_wheel_dir,
                     delocate_archs=delocate_archs,
@@ -446,7 +452,7 @@ def build(options: BuildOptions) -> None:
 
             log.step_end()
 
-            if options.test_command and options.test_selector(config.identifier):
+            if build_options.test_command and build_options.test_selector(config.identifier):
                 machine_arch = platform.machine()
                 testing_archs: List[Literal["x86_64", "arm64"]] = []
 
@@ -460,7 +466,7 @@ def build(options: BuildOptions) -> None:
                 for testing_arch in testing_archs:
                     if config_is_universal2:
                         arch_specific_identifier = f"{config.identifier}:{testing_arch}"
-                        if not options.test_selector(arch_specific_identifier):
+                        if not build_options.test_selector(arch_specific_identifier):
                             continue
 
                     if machine_arch == "x86_64" and testing_arch == "arm64":
@@ -541,31 +547,33 @@ def build(options: BuildOptions) -> None:
                     # check that we are using the Python from the virtual environment
                     call_with_arch(["which", "python"], env=virtualenv_env)
 
-                    if options.before_test:
+                    if build_options.before_test:
                         before_test_prepared = prepare_command(
-                            options.before_test, project=".", package=options.package_dir
+                            build_options.before_test,
+                            project=".",
+                            package=build_options.package_dir,
                         )
                         call_with_arch(before_test_prepared, env=virtualenv_env, shell=True)
 
                     # install the wheel
                     call_with_arch(
-                        ["pip", "install", f"{repaired_wheel}{options.test_extras}"],
+                        ["pip", "install", f"{repaired_wheel}{build_options.test_extras}"],
                         env=virtualenv_env,
                     )
 
                     # test the wheel
-                    if options.test_requires:
+                    if build_options.test_requires:
                         call_with_arch(
-                            ["pip", "install"] + options.test_requires, env=virtualenv_env
+                            ["pip", "install"] + build_options.test_requires, env=virtualenv_env
                         )
 
                     # run the tests from $HOME, with an absolute path in the command
                     # (this ensures that Python runs the tests against the installed wheel
                     # and not the repo code)
                     test_command_prepared = prepare_command(
-                        options.test_command,
+                        build_options.test_command,
                         project=Path(".").resolve(),
-                        package=options.package_dir.resolve(),
+                        package=build_options.package_dir.resolve(),
                     )
                     call_with_arch(
                         test_command_prepared,
@@ -578,7 +586,7 @@ def build(options: BuildOptions) -> None:
                     shutil.rmtree(venv_dir)
 
             # we're all done here; move it to output (overwrite existing)
-            shutil.move(str(repaired_wheel), options.output_dir)
+            shutil.move(str(repaired_wheel), build_options.output_dir)
             log.build_end()
     except subprocess.CalledProcessError as error:
         log.step_end_with_error(

cibuildwheel/options.py

@@ -2,31 +2,115 @@ import os
 import sys
 import traceback
 from configparser import ConfigParser
+from contextlib import contextmanager
 from pathlib import Path
-from typing import Any, Dict, List, Mapping, Optional, Set, Tuple, Union
+from typing import (
+    Any,
+    Dict,
+    Iterator,
+    List,
+    Mapping,
+    NamedTuple,
+    Optional,
+    Set,
+    Tuple,
+    Union,
+)
 
 import tomli
 from packaging.specifiers import SpecifierSet
 
 from .architecture import Architecture
-from .environment import EnvironmentParseError, parse_environment
+from .environment import EnvironmentParseError, ParsedEnvironment, parse_environment
 from .projectfiles import get_requires_python_str
-from .typing import PLATFORMS, PlatformName, TypedDict
+from .typing import PLATFORMS, Literal, PlatformName, TypedDict
 from .util import (
     MANYLINUX_ARCHS,
     MUSLLINUX_ARCHS,
     BuildFrontend,
-    BuildOptions,
     BuildSelector,
     DependencyConstraints,
     TestSelector,
     resources_dir,
+    selector_matches,
     strtobool,
+    unwrap,
 )
 
+
+class CommandLineArguments:
+    platform: Literal["auto", "linux", "macos", "windows"]
+    archs: Optional[str]
+    output_dir: Optional[str]
+    config_file: Optional[str]
+    package_dir: str
+    print_build_identifiers: bool
+    allow_empty: bool
+    prerelease_pythons: bool
+
+
+class GlobalOptions(NamedTuple):
+    package_dir: Path
+    output_dir: Path
+    build_selector: BuildSelector
+    test_selector: TestSelector
+    architectures: Set[Architecture]
+
+
+class BuildOptions(NamedTuple):
+    globals: GlobalOptions
+    environment: ParsedEnvironment
+    before_all: str
+    before_build: Optional[str]
+    repair_command: str
+    manylinux_images: Optional[Dict[str, str]]
+    musllinux_images: Optional[Dict[str, str]]
+    dependency_constraints: Optional[DependencyConstraints]
+    test_command: Optional[str]
+    before_test: Optional[str]
+    test_requires: List[str]
+    test_extras: str
+    build_verbosity: int
+    build_frontend: BuildFrontend
+
+    @property
+    def package_dir(self) -> Path:
+        return self.globals.package_dir
+
+    @property
+    def output_dir(self) -> Path:
+        return self.globals.output_dir
+
+    @property
+    def build_selector(self) -> BuildSelector:
+        return self.globals.build_selector
+
+    @property
+    def test_selector(self) -> TestSelector:
+        return self.globals.test_selector
+
+    @property
+    def architectures(self) -> Set[Architecture]:
+        return self.globals.architectures
+
+
 Setting = Union[Dict[str, str], List[str], str]
 
 
+class Override(NamedTuple):
+    select_pattern: str
+    options: Dict[str, Setting]
+
+
+MANYLINUX_OPTIONS = {f"manylinux-{build_platform}-image" for build_platform in MANYLINUX_ARCHS}
+MUSLLINUX_OPTIONS = {f"musllinux-{build_platform}-image" for build_platform in MUSLLINUX_ARCHS}
+DISALLOWED_OPTIONS = {
+    "linux": {"dependency-versions"},
+    "macos": MANYLINUX_OPTIONS | MUSLLINUX_OPTIONS,
+    "windows": MANYLINUX_OPTIONS | MUSLLINUX_OPTIONS,
+}
+
+
 class TableFmt(TypedDict):
     item: str
     sep: str
@@ -58,29 +142,28 @@ def _dig_first(*pairs: Tuple[Mapping[str, Setting], str], ignore_empty: bool = F
     raise KeyError(key)
 
 
-class ConfigOptions:
+class OptionsReader:
     """
     Gets options from the environment, config or defaults, optionally scoped
     by the platform.
 
     Example:
-      >>> options = ConfigOptions(package_dir, platform='macos')
+      >>> options_reader = OptionsReader(config_file, platform='macos')
-      >>> options('cool-color')
+      >>> options_reader.get('cool-color')
 
       This will return the value of CIBW_COOL_COLOR_MACOS if it exists,
       otherwise the value of CIBW_COOL_COLOR, otherwise
       'tool.cibuildwheel.macos.cool-color' or 'tool.cibuildwheel.cool-color'
-      from pyproject.toml, or from cibuildwheel/resources/defaults.toml. An
+      from `config_file`, or from cibuildwheel/resources/defaults.toml. An
       error is thrown if there are any unexpected keys or sections in
       tool.cibuildwheel.
     """
 
     def __init__(
         self,
-        package_path: Path,
+        config_file_path: Optional[Path] = None,
-        config_file: Optional[str] = None,
         *,
-        platform: str,
+        platform: PlatformName,
         disallow: Optional[Dict[str, Set[str]]] = None,
     ) -> None:
         self.platform = platform
@@ -94,14 +177,8 @@ class ConfigOptions:
         config_options: Dict[str, Any] = {}
         config_platform_options: Dict[str, Any] = {}
 
-        if config_file is not None:
+        if config_file_path is not None:
-            config_path = Path(config_file.format(package=package_path))
+            config_options, config_platform_options = self._load_file(config_file_path)
-            config_options, config_platform_options = self._load_file(config_path)
-        else:
-            # load pyproject.toml, if it's available
-            pyproject_toml_path = package_path / "pyproject.toml"
-            if pyproject_toml_path.exists():
-                config_options, config_platform_options = self._load_file(pyproject_toml_path)
 
         # Validate project config
         for option_name in config_options:
@@ -117,12 +194,32 @@ class ConfigOptions:
         self.config_options = config_options
         self.config_platform_options = config_platform_options
 
+        self.overrides: List[Override] = []
+        self.current_identifier: Optional[str] = None
+
+        config_overrides = self.config_options.get("overrides")
+
+        if config_overrides is not None:
+            if not isinstance(config_overrides, list):
+                raise ConfigOptionError('"tool.cibuildwheel.overrides" must be a list')
+
+            for config_override in config_overrides:
+                select = config_override.pop("select", None)
+
+                if not select:
+                    raise ConfigOptionError('"select" must be set in an override')
+
+                if isinstance(select, list):
+                    select = " ".join(select)
+
+                self.overrides.append(Override(select, config_override))
+
     def _is_valid_global_option(self, name: str) -> bool:
         """
         Returns True if an option with this name is allowed in the
         [tool.cibuildwheel] section of a config file.
         """
-        allowed_option_names = self.default_options.keys() | PLATFORMS
+        allowed_option_names = self.default_options.keys() | PLATFORMS | {"overrides"}
 
         return name in allowed_option_names
 
@@ -151,7 +248,23 @@ class ConfigOptions:
 
         return global_options, platform_options
 
-    def __call__(
+    @property
+    def active_config_overrides(self) -> List[Override]:
+        if self.current_identifier is None:
+            return []
+        return [
+            o for o in self.overrides if selector_matches(o.select_pattern, self.current_identifier)
+        ]
+
+    @contextmanager
+    def identifier(self, identifier: Optional[str]) -> Iterator[None]:
+        self.current_identifier = identifier
+        try:
+            yield
+        finally:
+            self.current_identifier = None
+
+    def get(
         self,
         name: str,
         *,
@@ -177,11 +290,15 @@ class ConfigOptions:
         envvar = f"CIBW_{name.upper().replace('-', '_')}"
         plat_envvar = f"{envvar}_{self.platform.upper()}"
 
+        # later overrides take precedence over earlier ones, so reverse the list
+        active_config_overrides = reversed(self.active_config_overrides)
+
         # get the option from the environment, then the config file, then finally the default.
         # platform-specific options are preferred, if they're allowed.
         result = _dig_first(
             (os.environ if env_plat else {}, plat_envvar),  # type: ignore[arg-type]
             (os.environ, envvar),
+            *[(o.options, name) for o in active_config_overrides],
             (self.config_platform_options, name),
             (self.config_options, name),
             (self.default_platform_options, name),
@@ -203,56 +320,60 @@ class ConfigOptions:
             return result
 
 
-def compute_options(
+class Options:
-    platform: PlatformName,
+    def __init__(self, platform: PlatformName, command_line_arguments: CommandLineArguments):
-    package_dir: Path,
+        self.platform = platform
-    output_dir: Path,
+        self.command_line_arguments = command_line_arguments
-    config_file: Optional[str],
-    args_archs: Optional[str],
-    prerelease_pythons: bool,
-) -> BuildOptions:
-    """
-    Compute the options from the environment and configuration file.
-    """
 
-    manylinux_identifiers = {
+        self.reader = OptionsReader(
-        f"manylinux-{build_platform}-image" for build_platform in MANYLINUX_ARCHS
+            self.config_file_path,
-    }
+            platform=platform,
-    musllinux_identifiers = {
+            disallow=DISALLOWED_OPTIONS,
-        f"musllinux-{build_platform}-image" for build_platform in MUSLLINUX_ARCHS
+        )
-    }
-    disallow = {
-        "linux": {"dependency-versions"},
-        "macos": manylinux_identifiers | musllinux_identifiers,
-        "windows": manylinux_identifiers | musllinux_identifiers,
-    }
-    options = ConfigOptions(package_dir, config_file, platform=platform, disallow=disallow)
 
-    build_config = options("build", env_plat=False, sep=" ") or "*"
+    @property
-    skip_config = options("skip", env_plat=False, sep=" ")
+    def config_file_path(self) -> Optional[Path]:
-    test_skip = options("test-skip", env_plat=False, sep=" ")
+        args = self.command_line_arguments
 
-    prerelease_pythons = prerelease_pythons or strtobool(
+        if args.config_file is not None:
+            return Path(args.config_file.format(package=args.package_dir))
+        # return pyproject.toml, if it's available
+        pyproject_toml_path = Path(args.package_dir) / "pyproject.toml"
+        if pyproject_toml_path.exists():
+            return pyproject_toml_path
+
+        return None
+
+    @property
+    def package_requires_python_str(self) -> Optional[str]:
+        if not hasattr(self, "_package_requires_python_str"):
+            args = self.command_line_arguments
+            self._package_requires_python_str = get_requires_python_str(Path(args.package_dir))
+        return self._package_requires_python_str
+
+    @property
+    def globals(self) -> GlobalOptions:
+        args = self.command_line_arguments
+        package_dir = Path(args.package_dir)
+        output_dir = Path(
+            args.output_dir
+            if args.output_dir is not None
+            else os.environ.get("CIBW_OUTPUT_DIR", "wheelhouse")
+        )
+
+        build_config = self.reader.get("build", env_plat=False, sep=" ") or "*"
+        skip_config = self.reader.get("skip", env_plat=False, sep=" ")
+        test_skip = self.reader.get("test-skip", env_plat=False, sep=" ")
+
+        prerelease_pythons = args.prerelease_pythons or strtobool(
             os.environ.get("CIBW_PRERELEASE_PYTHONS", "0")
         )
 
-    deprecated_selectors("CIBW_BUILD", build_config, error=True)
-    deprecated_selectors("CIBW_SKIP", skip_config)
-    deprecated_selectors("CIBW_TEST_SKIP", test_skip)
-
-    package_files = {"setup.py", "setup.cfg", "pyproject.toml"}
-
-    if not any(package_dir.joinpath(name).exists() for name in package_files):
-        names = ", ".join(sorted(package_files, reverse=True))
-        msg = f"cibuildwheel: Could not find any of {{{names}}} at root of package"
-        print(msg, file=sys.stderr)
-        sys.exit(2)
-
         # This is not supported in tool.cibuildwheel, as it comes from a standard location.
         # Passing this in as an environment variable will override pyproject.toml, setup.cfg, or setup.py
-    requires_python_str: Optional[str] = os.environ.get(
+        requires_python_str: Optional[str] = (
-        "CIBW_PROJECT_REQUIRES_PYTHON"
+            os.environ.get("CIBW_PROJECT_REQUIRES_PYTHON") or self.package_requires_python_str
-    ) or get_requires_python_str(package_dir)
+        )
         requires_python = None if requires_python_str is None else SpecifierSet(requires_python_str)
 
         build_selector = BuildSelector(
@@ -263,39 +384,38 @@ def compute_options(
         )
         test_selector = TestSelector(skip_config=test_skip)
 
-    return _compute_single_options(
+        archs_config_str = args.archs or self.reader.get("archs", sep=" ")
-        options, args_archs, build_selector, test_selector, platform, package_dir, output_dir
+        architectures = Architecture.parse_config(archs_config_str, platform=self.platform)
+
+        return GlobalOptions(
+            package_dir=package_dir,
+            output_dir=output_dir,
+            build_selector=build_selector,
+            test_selector=test_selector,
+            architectures=architectures,
         )
 
-
+    def build_options(self, identifier: Optional[str]) -> BuildOptions:
-def _compute_single_options(
-    options: ConfigOptions,
-    args_archs: Optional[str],
-    build_selector: BuildSelector,
-    test_selector: TestSelector,
-    platform: PlatformName,
-    package_dir: Path,
-    output_dir: Path,
-) -> BuildOptions:
         """
         Compute BuildOptions for a single run configuration.
         """
-    # Can't be configured per selector
-    before_all = options("before-all", sep=" && ")
 
-    archs_config_str = args_archs or options("archs", sep=" ")
+        with self.reader.identifier(identifier):
+            before_all = self.reader.get("before-all", sep=" && ")
 
-    build_frontend_str = options("build-frontend", env_plat=False)
+            build_frontend_str = self.reader.get("build-frontend", env_plat=False)
-    environment_config = options("environment", table={"item": '{k}="{v}"', "sep": " "})
+            environment_config = self.reader.get(
-    before_build = options("before-build", sep=" && ")
+                "environment", table={"item": '{k}="{v}"', "sep": " "}
-    repair_command = options("repair-wheel-command", sep=" && ")
+            )
+            before_build = self.reader.get("before-build", sep=" && ")
+            repair_command = self.reader.get("repair-wheel-command", sep=" && ")
 
-    dependency_versions = options("dependency-versions")
+            dependency_versions = self.reader.get("dependency-versions")
-    test_command = options("test-command", sep=" && ")
+            test_command = self.reader.get("test-command", sep=" && ")
-    before_test = options("before-test", sep=" && ")
+            before_test = self.reader.get("before-test", sep=" && ")
-    test_requires = options("test-requires", sep=" ").split()
+            test_requires = self.reader.get("test-requires", sep=" ").split()
-    test_extras = options("test-extras", sep=",")
+            test_extras = self.reader.get("test-extras", sep=",")
-    build_verbosity_str = options("build-verbosity")
+            build_verbosity_str = self.reader.get("build-verbosity")
 
             build_frontend: BuildFrontend
             if build_frontend_str == "build":
@@ -303,14 +423,17 @@ def _compute_single_options(
             elif build_frontend_str == "pip":
                 build_frontend = "pip"
             else:
-        msg = f"cibuildwheel: Unrecognised build frontend '{build_frontend}', only 'pip' and 'build' are supported"
+                msg = f"cibuildwheel: Unrecognised build frontend '{build_frontend_str}', only 'pip' and 'build' are supported"
                 print(msg, file=sys.stderr)
                 sys.exit(2)
 
             try:
                 environment = parse_environment(environment_config)
             except (EnvironmentParseError, ValueError):
-        print(f'cibuildwheel: Malformed environment option "{environment_config}"', file=sys.stderr)
+                print(
+                    f'cibuildwheel: Malformed environment option "{environment_config}"',
+                    file=sys.stderr,
+                )
                 traceback.print_exc(None, sys.stderr)
                 sys.exit(2)
 
@@ -332,42 +455,38 @@ def _compute_single_options(
             except ValueError:
                 build_verbosity = 0
 
-    archs = Architecture.parse_config(archs_config_str, platform=platform)
-
             manylinux_images: Dict[str, str] = {}
             musllinux_images: Dict[str, str] = {}
-    if platform == "linux":
+            if self.platform == "linux":
-        pinned_docker_images_file = resources_dir / "pinned_docker_images.cfg"
+                all_pinned_docker_images = _get_pinned_docker_images()
-        all_pinned_docker_images = ConfigParser()
-        all_pinned_docker_images.read(pinned_docker_images_file)
-        # all_pinned_docker_images looks like a dict of dicts, e.g.
-        # { 'x86_64': {'manylinux1': '...', 'manylinux2010': '...', 'manylinux2014': '...'},
-        #   'i686': {'manylinux1': '...', 'manylinux2010': '...', 'manylinux2014': '...'},
-        #   'pypy_x86_64': {'manylinux2010': '...' }
-        #   ... }
 
                 for build_platform in MANYLINUX_ARCHS:
                     pinned_images = all_pinned_docker_images[build_platform]
 
-            config_value = options(f"manylinux-{build_platform}-image", ignore_empty=True)
+                    config_value = self.reader.get(
+                        f"manylinux-{build_platform}-image", ignore_empty=True
+                    )
 
                     if not config_value:
                         # default to manylinux2010 if it's available, otherwise manylinux2014
-                image = pinned_images.get("manylinux2010") or pinned_images.get("manylinux2014")
+                        image = pinned_images.get("manylinux2010") or pinned_images.get(
+                            "manylinux2014"
+                        )
                     elif config_value in pinned_images:
                         image = pinned_images[config_value]
                     else:
                         image = config_value
 
+                    assert image is not None
                     manylinux_images[build_platform] = image
 
                 for build_platform in MUSLLINUX_ARCHS:
                     pinned_images = all_pinned_docker_images[build_platform]
 
-            config_value = options(f"musllinux-{build_platform}-image")
+                    config_value = self.reader.get(f"musllinux-{build_platform}-image")
 
                     if config_value is None:
-                image = pinned_images.get("musllinux_1_1")
+                        image = pinned_images["musllinux_1_1"]
                     elif config_value in pinned_images:
                         image = pinned_images[config_value]
                     else:
@@ -376,9 +495,7 @@ def _compute_single_options(
                     musllinux_images[build_platform] = image
 
             return BuildOptions(
-        architectures=archs,
+                globals=self.globals,
-        package_dir=package_dir,
-        output_dir=output_dir,
                 test_command=test_command,
                 test_requires=test_requires,
                 test_extras=test_extras,
@@ -386,8 +503,6 @@ def _compute_single_options(
                 before_build=before_build,
                 before_all=before_all,
                 build_verbosity=build_verbosity,
-        build_selector=build_selector,
-        test_selector=test_selector,
                 repair_command=repair_command,
                 environment=environment,
                 dependency_constraints=dependency_constraints,
@@ -396,6 +511,80 @@ def _compute_single_options(
                 build_frontend=build_frontend,
             )
 
+    def check_for_invalid_configuration(self, identifiers: List[str]) -> None:
+        if self.platform in ["macos", "windows"]:
+            before_all_values = {self.build_options(i).before_all for i in identifiers}
+
+            if len(before_all_values) > 1:
+                raise ValueError(
+                    unwrap(
+                        f"""
+                        before_all cannot be set to multiple values. On macOS and Windows,
+                        before_all is only run once, at the start of the build. before_all values
+                        are: {before_all_values!r}
+                        """
+                    )
+                )
+
+    def check_for_deprecated_options(self) -> None:
+        build_selector = self.globals.build_selector
+        test_selector = self.globals.test_selector
+
+        deprecated_selectors("CIBW_BUILD", build_selector.build_config, error=True)
+        deprecated_selectors("CIBW_SKIP", build_selector.skip_config)
+        deprecated_selectors("CIBW_TEST_SKIP", test_selector.skip_config)
+
+    def summary(self, identifiers: List[str]) -> str:
+        lines = [
+            f"{option_name}: {option_value!r}"
+            for option_name, option_value in sorted(self.globals._asdict().items())
+        ]
+
+        build_option_defaults = self.build_options(identifier=None)
+
+        for option_name, default_value in sorted(build_option_defaults._asdict().items()):
+            if option_name == "globals":
+                continue
+
+            lines.append(f"{option_name}: {default_value!r}")
+
+            # if any identifiers have an overridden value, print that too
+            for identifier in identifiers:
+                option_value = self.build_options(identifier=identifier)._asdict()[option_name]
+                if option_value != default_value:
+                    lines.append(f"  {identifier}: {option_value!r}")
+
+        return "\n".join(lines)
+
+
+def compute_options(
+    platform: PlatformName,
+    command_line_arguments: CommandLineArguments,
+) -> Options:
+    options = Options(platform=platform, command_line_arguments=command_line_arguments)
+    options.check_for_deprecated_options()
+    return options
+
+
+_all_pinned_docker_images: Optional[ConfigParser] = None
+
+
+def _get_pinned_docker_images() -> Mapping[str, Mapping[str, str]]:
+    """
+    This looks like a dict of dicts, e.g.
+    { 'x86_64': {'manylinux1': '...', 'manylinux2010': '...', 'manylinux2014': '...'},
+      'i686': {'manylinux1': '...', 'manylinux2010': '...', 'manylinux2014': '...'},
+      'pypy_x86_64': {'manylinux2010': '...' }
+      ... }
+    """
+    global _all_pinned_docker_images
+
+    if _all_pinned_docker_images is None:
+        pinned_docker_images_file = resources_dir / "pinned_docker_images.cfg"
+        _all_pinned_docker_images = ConfigParser()
+        _all_pinned_docker_images.read(pinned_docker_images_file)
+    return _all_pinned_docker_images
+
 
 def deprecated_selectors(name: str, selector: str, *, error: bool = False) -> None:
     if "p2" in selector or "p35" in selector:

cibuildwheel/typing.py

@@ -4,22 +4,25 @@ import sys
 from typing import TYPE_CHECKING, NoReturn, Set, Union
 
 if sys.version_info < (3, 8):
-    from typing_extensions import Final, Literal, Protocol, TypedDict
+    from typing_extensions import Final, Literal, OrderedDict, Protocol, TypedDict
 else:
-    from typing import Final, Literal, Protocol, TypedDict
+    from typing import Final, Literal, OrderedDict, Protocol, TypedDict
 
 
 __all__ = (
     "Final",
     "Literal",
-    "TypedDict",
+    "PLATFORMS",
-    "Set",
-    "Union",
-    "PopenBytes",
     "PathOrStr",
     "PlatformName",
     "Protocol",
     "PLATFORMS",
+    "PopenBytes",
+    "Protocol",
+    "Set",
+    "TypedDict",
+    "OrderedDict",
+    "Union",
     "assert_never",
 )
 

cibuildwheel/util.py

@@ -12,7 +12,7 @@ import urllib.request
 from enum import Enum
 from pathlib import Path
 from time import sleep
-from typing import Dict, Iterator, List, NamedTuple, Optional, Set
+from typing import Dict, Iterator, List, Optional
 
 import bracex
 import certifi
@@ -20,8 +20,6 @@ import tomli
 from packaging.specifiers import SpecifierSet
 from packaging.version import Version
 
-from .architecture import Architecture
-from .environment import ParsedEnvironment
 from .typing import Literal, PathOrStr, PlatformName
 
 resources_dir = Path(__file__).parent / "resources"
@@ -77,6 +75,20 @@ def read_python_configs(config: PlatformName) -> List[Dict[str, str]]:
     return results
 
 
+def selector_matches(patterns: str, string: str) -> bool:
+    """
+    Returns True if `string` is matched by any of the wildcard patterns in
+    `patterns`.
+
+    Matching is according to fnmatch, but with shell-like curly brace
+    expansion. For example, 'cp{36,37}-*' would match either of 'cp36-*' or
+    'cp37-*'.
+    """
+    patterns_list: List[str] = patterns.split()
+    patterns_list = itertools.chain.from_iterable(bracex.expand(p) for p in patterns_list)  # type: ignore[assignment]
+    return any(fnmatch.fnmatch(string, pat) for pat in patterns_list)
+
+
 class IdentifierSelector:
     """
     This class holds a set of build/skip patterns. You call an instance with a
@@ -97,8 +109,8 @@ class IdentifierSelector:
         requires_python: Optional[SpecifierSet] = None,
         prerelease_pythons: bool = False,
     ):
-        self.build_patterns = build_config.split()
+        self.build_config = build_config
-        self.skip_patterns = skip_config.split()
+        self.skip_config = skip_config
         self.requires_python = requires_python
         self.prerelease_pythons = prerelease_pythons
 
@@ -112,30 +124,22 @@ class IdentifierSelector:
             if not self.requires_python.contains(version):
                 return False
 
-        build_patterns = itertools.chain.from_iterable(
+        # filter out the prerelease pythons if self.prerelease_pythons is False
-            bracex.expand(p) for p in self.build_patterns
+        if not self.prerelease_pythons and selector_matches(
-        )
+            BuildSelector.PRERELEASE_SKIP, build_id
+        ):
+            return False
 
-        unexpanded_skip_patterns = self.skip_patterns.copy()
+        should_build = selector_matches(self.build_config, build_id)
+        should_skip = selector_matches(self.skip_config, build_id)
 
-        if not self.prerelease_pythons:
+        return should_build and not should_skip
-            # filter out the prerelease pythons, alongside the user-defined
-            # skip patterns
-            unexpanded_skip_patterns += BuildSelector.PRERELEASE_SKIP.split()
-
-        skip_patterns = itertools.chain.from_iterable(
-            bracex.expand(p) for p in unexpanded_skip_patterns
-        )
-
-        build: bool = any(fnmatch.fnmatch(build_id, pat) for pat in build_patterns)
-        skip: bool = any(fnmatch.fnmatch(build_id, pat) for pat in skip_patterns)
-        return build and not skip
 
     def __repr__(self) -> str:
-        result = f'{self.__class__.__name__}(build_config={" ".join(self.build_patterns)!r}'
+        result = f"{self.__class__.__name__}(build_config={self.build_config!r}"
 
-        if self.skip_patterns:
+        if self.skip_config:
-            result += f', skip_config={" ".join(self.skip_patterns)!r}'
+            result += f", skip_config={self.skip_config!r}"
         if self.prerelease_pythons:
             result += ", prerelease_pythons=True"
 
@@ -222,32 +226,13 @@ class DependencyConstraints:
             return self.base_file_path
 
     def __repr__(self) -> str:
-        return f"{self.__class__.__name__}{self.base_file_path!r})"
+        return f"{self.__class__.__name__}({self.base_file_path!r})"
 
+    def __eq__(self, o: object) -> bool:
+        if not isinstance(o, DependencyConstraints):
+            return False
 
-class BuildOptions(NamedTuple):
+        return self.base_file_path == o.base_file_path
-    package_dir: Path
-    output_dir: Path
-    build_selector: BuildSelector
-    architectures: Set[Architecture]
-    environment: ParsedEnvironment
-    before_all: str
-    before_build: Optional[str]
-    repair_command: str
-    manylinux_images: Optional[Dict[str, str]]
-    musllinux_images: Optional[Dict[str, str]]
-    dependency_constraints: Optional[DependencyConstraints]
-    test_command: Optional[str]
-    test_selector: TestSelector
-    before_test: Optional[str]
-    test_requires: List[str]
-    test_extras: str
-    build_verbosity: int
-    build_frontend: BuildFrontend
-
-    def __str__(self) -> str:
-        res = (f"{option}: {value!r}" for option, value in sorted(self._asdict().items()))
-        return "\n".join(res)
 
 
 class NonPlatformWheelError(Exception):

cibuildwheel/windows.py

@@ -10,10 +10,10 @@ from zipfile import ZipFile
 from .architecture import Architecture
 from .environment import ParsedEnvironment
 from .logger import log
+from .options import Options
 from .typing import PathOrStr, assert_never
 from .util import (
     BuildFrontend,
-    BuildOptions,
     BuildSelector,
     NonPlatformWheelError,
     download,
@@ -246,47 +246,51 @@ def setup_python(
     return env
 
 
-def build(options: BuildOptions) -> None:
+def build(options: Options) -> None:
     temp_dir = Path(tempfile.mkdtemp(prefix="cibuildwheel"))
     built_wheel_dir = temp_dir / "built_wheel"
     repaired_wheel_dir = temp_dir / "repaired_wheel"
 
+    python_configurations = get_python_configurations(
+        options.globals.build_selector, options.globals.architectures
+    )
+
     try:
-        if options.before_all:
+        before_all_options_identifier = python_configurations[0].identifier
+        before_all_options = options.build_options(before_all_options_identifier)
+
+        if before_all_options.before_all:
             log.step("Running before_all...")
-            env = options.environment.as_dictionary(prev_environment=os.environ)
+            env = before_all_options.environment.as_dictionary(prev_environment=os.environ)
             before_all_prepared = prepare_command(
-                options.before_all, project=".", package=options.package_dir
+                before_all_options.before_all, project=".", package=options.globals.package_dir
             )
             shell(before_all_prepared, env=env)
 
-        python_configurations = get_python_configurations(
-            options.build_selector, options.architectures
-        )
-
         for config in python_configurations:
+            build_options = options.build_options(config.identifier)
             log.build_start(config.identifier)
 
             dependency_constraint_flags: Sequence[PathOrStr] = []
-            if options.dependency_constraints:
+            if build_options.dependency_constraints:
                 dependency_constraint_flags = [
                     "-c",
-                    options.dependency_constraints.get_for_python_version(config.version),
+                    build_options.dependency_constraints.get_for_python_version(config.version),
                 ]
 
             # install Python
             env = setup_python(
                 config,
                 dependency_constraint_flags,
-                options.environment,
+                build_options.environment,
-                options.build_frontend,
+                build_options.build_frontend,
             )
 
             # run the before_build command
-            if options.before_build:
+            if build_options.before_build:
                 log.step("Running before_build...")
                 before_build_prepared = prepare_command(
-                    options.before_build, project=".", package=options.package_dir
+                    build_options.before_build, project=".", package=options.globals.package_dir
                 )
                 shell(before_build_prepared, env=env)
 
@@ -295,9 +299,9 @@ def build(options: BuildOptions) -> None:
                 shutil.rmtree(built_wheel_dir)
             built_wheel_dir.mkdir(parents=True)
 
-            verbosity_flags = get_build_verbosity_extra_flags(options.build_verbosity)
+            verbosity_flags = get_build_verbosity_extra_flags(build_options.build_verbosity)
 
-            if options.build_frontend == "pip":
+            if build_options.build_frontend == "pip":
                 # Path.resolve() is needed. Without it pip wheel may try to fetch package from pypi.org
                 # see https://github.com/pypa/cibuildwheel/pull/369
                 call(
@@ -306,18 +310,18 @@ def build(options: BuildOptions) -> None:
                         "-m",
                         "pip",
                         "wheel",
-                        options.package_dir.resolve(),
+                        options.globals.package_dir.resolve(),
                         f"--wheel-dir={built_wheel_dir}",
                         "--no-deps",
-                        *get_build_verbosity_extra_flags(options.build_verbosity),
+                        *get_build_verbosity_extra_flags(build_options.build_verbosity),
                     ],
                     env=env,
                 )
-            elif options.build_frontend == "build":
+            elif build_options.build_frontend == "build":
                 config_setting = " ".join(verbosity_flags)
                 build_env = env.copy()
-                if options.dependency_constraints:
+                if build_options.dependency_constraints:
-                    constraints_path = options.dependency_constraints.get_for_python_version(
+                    constraints_path = build_options.dependency_constraints.get_for_python_version(
                         config.version
                     )
                     # Bug in pip <= 21.1.3 - we can't have a space in the
@@ -339,7 +343,7 @@ def build(options: BuildOptions) -> None:
                             "python",
                             "-m",
                             "build",
-                            options.package_dir,
+                            build_options.package_dir,
                             "--wheel",
                             f"--outdir={built_wheel_dir}",
                             f"--config-setting={config_setting}",
@@ -347,7 +351,7 @@ def build(options: BuildOptions) -> None:
                         env=build_env,
                     )
             else:
-                assert_never(options.build_frontend)
+                assert_never(build_options.build_frontend)
 
             built_wheel = next(built_wheel_dir.glob("*.whl"))
 
@@ -359,10 +363,10 @@ def build(options: BuildOptions) -> None:
             if built_wheel.name.endswith("none-any.whl"):
                 raise NonPlatformWheelError()
 
-            if options.repair_command:
+            if build_options.repair_command:
                 log.step("Repairing wheel...")
                 repair_command_prepared = prepare_command(
-                    options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir
+                    build_options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir
                 )
                 shell(repair_command_prepared, env=env)
             else:
@@ -370,7 +374,7 @@ def build(options: BuildOptions) -> None:
 
             repaired_wheel = next(repaired_wheel_dir.glob("*.whl"))
 
-            if options.test_command and options.test_selector(config.identifier):
+            if build_options.test_command and options.globals.test_selector(config.identifier):
                 log.step("Testing wheel...")
                 # set up a virtual environment to install and test from, to make sure
                 # there are no dependencies that were pulled in at build time.
@@ -392,31 +396,31 @@ def build(options: BuildOptions) -> None:
                 # check that we are using the Python from the virtual environment
                 call(["where", "python"], env=virtualenv_env)
 
-                if options.before_test:
+                if build_options.before_test:
                     before_test_prepared = prepare_command(
-                        options.before_test,
+                        build_options.before_test,
                         project=".",
-                        package=options.package_dir,
+                        package=build_options.package_dir,
                     )
                     shell(before_test_prepared, env=virtualenv_env)
 
                 # install the wheel
                 call(
-                    ["pip", "install", str(repaired_wheel) + options.test_extras],
+                    ["pip", "install", str(repaired_wheel) + build_options.test_extras],
                     env=virtualenv_env,
                 )
 
                 # test the wheel
-                if options.test_requires:
+                if build_options.test_requires:
-                    call(["pip", "install"] + options.test_requires, env=virtualenv_env)
+                    call(["pip", "install"] + build_options.test_requires, env=virtualenv_env)
 
                 # run the tests from c:\, with an absolute path in the command
                 # (this ensures that Python runs the tests against the installed wheel
                 # and not the repo code)
                 test_command_prepared = prepare_command(
-                    options.test_command,
+                    build_options.test_command,
                     project=Path(".").resolve(),
-                    package=options.package_dir.resolve(),
+                    package=options.globals.package_dir.resolve(),
                 )
                 shell(test_command_prepared, cwd="c:\\", env=virtualenv_env)
 
@@ -424,7 +428,7 @@ def build(options: BuildOptions) -> None:
                 shutil.rmtree(venv_dir)
 
             # we're all done here; move it to output (remove if already exists)
-            shutil.move(str(repaired_wheel), options.output_dir)
+            shutil.move(str(repaired_wheel), build_options.output_dir)
             log.build_end()
     except subprocess.CalledProcessError as error:
         log.step_end_with_error(

docs/options.md

@@ -107,6 +107,56 @@ The complete set of defaults for the current version of cibuildwheel are shown b
     not want to change a `pyproject.toml` file. You can specify a different file to
     use with `--config-file` on the command line, as well.
 
+### Configuration overrides {: #overrides }
+
+One feature specific to the configuration files is the ability to override
+settings based on selectors. To use, add a ``tool.cibuildwheel.overrides``
+array, and specify a ``select`` string. Then any options you set will only
+apply to items that match that selector. These are applied in order, with later
+matches overriding earlier ones if multiple selectors match. Environment
+variables always override static configuration.
+
+A few of the options below have special handling in overrides. A different
+`before-all` will trigger a new docker launch on Linux, and cannot be
+overridden on macOS or Windows.  Overriding the image on linux will also
+generate new docker launches, one per image.  Some commands are not supported;
+`output-dir`, build/skip/test_skip selectors, and architectures cannot be
+overridden.
+
+##### Examples:
+
+```toml
+[tool.cibuildwheel.linux]
+before-all = "yum install mylib"
+test-command = "echo 'installed'"
+
+[[tool.cibuildwheel.overrides]]
+select = "*-musllinux*"
+before-all = "apk add mylib"
+```
+
+This example will override the before-all command on musllinux only, but will
+still run the test-command. Note the double brackets, this is an array in TOML,
+which means it can be given multiple times.
+
+```toml
+[tool.cibuildwheel]
+# Normal options, etc.
+manylinux-x86_64-image = "manylinux2010"
+
+[[tool.cibuildwheel.overrides]]
+select = "cp36-*"
+manylinux-x86_64-image = "manylinux1"
+
+[[tool.cibuildwheel.overrides]]
+select = "cp310-*"
+manylinux-x86_64-image = "manylinux2014"
+```
+
+This example will build CPython 3.6 wheels on manylinux1, CPython 3.7-3.9
+images on manylinux2010, and CPython 3.10 wheels on manylinux2014.
+
+
 ## Options summary
 
 <div class="options-toc"></div>
@@ -305,7 +355,8 @@ If not listed above, `auto` is the same as `native`.
 Platform-specific environment variables are also available:<br/>
  `CIBW_ARCHS_MACOS` | `CIBW_ARCHS_WINDOWS` | `CIBW_ARCHS_LINUX`
 
-This option can also be set using the [command-line option](#command-line) `--archs`.
+This option can also be set using the [command-line option](#command-line)
+`--archs`. This option cannot be set in an `overrides` section in `pyproject.toml`.
 
 #### Examples
 
@@ -564,6 +615,10 @@ The placeholder `{package}` can be used here; it will be replaced by the path to
 
 On Windows and macOS, the version of Python available inside `CIBW_BEFORE_ALL` is whatever is available on the host machine. On Linux, a modern Python version is available on PATH.
 
+This option has special behavior in the overrides section in `pyproject.toml`.
+On linux, overriding it triggers a new docker launch. It cannot be overridden
+on macOS and Windows.
+
 Platform-specific environment variables also available:<br/>
 `CIBW_BEFORE_ALL_MACOS` | `CIBW_BEFORE_ALL_WINDOWS` | `CIBW_BEFORE_ALL_LINUX`
 
@@ -1144,6 +1199,8 @@ This will skip testing on any identifiers that match the given skip patterns (se
 
 With macOS `universal2` wheels, you can also skip the individual archs inside the wheel using an `:arch` suffix. For example, `cp39-macosx_universal2:x86_64` or `cp39-macosx_universal2:arm64`.
 
+This option is not supported in the overrides section in `pyproject.toml`.
+
 #### Examples
 
 !!! tab examples "Environment variables"

setup.cfg

@@ -36,6 +36,7 @@ install_requires =
     certifi
     packaging
     tomli
+    dataclasses;python_version < '3.7'
     typing_extensions;python_version < '3.8'
 python_requires = >=3.6
 include_package_data = True

unit_test/conftest.py

@@ -1,5 +1,10 @@
+import sys
+from pathlib import Path
+
 import pytest
 
+MOCK_PACKAGE_DIR = Path("some_package_dir")
+
 
 def pytest_addoption(parser):
     parser.addoption("--run-docker", action="store_true", default=False, help="run docker tests")
@@ -17,3 +22,22 @@ def pytest_collection_modifyitems(config, items):
     for item in items:
         if "docker" in item.keywords:
             item.add_marker(skip_docker)
+
+
+@pytest.fixture
+def fake_package_dir(monkeypatch):
+    """
+    Monkey-patch enough for the main() function to run
+    """
+    real_path_exists = Path.exists
+
+    def mock_path_exists(path):
+        if path == MOCK_PACKAGE_DIR / "setup.py":
+            return True
+        else:
+            return real_path_exists(path)
+
+    args = ["cibuildwheel", str(MOCK_PACKAGE_DIR)]
+    monkeypatch.setattr(Path, "exists", mock_path_exists)
+    monkeypatch.setattr(sys, "argv", args)
+    return args

unit_test/docker_container_test.py

@@ -25,19 +25,19 @@ elif pm == "s390x":
 
 @pytest.mark.docker
 def test_simple():
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         assert container.call(["echo", "hello"], capture_output=True) == "hello\n"
 
 
 @pytest.mark.docker
 def test_no_lf():
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         assert container.call(["printf", "hello"], capture_output=True) == "hello"
 
 
 @pytest.mark.docker
 def test_environment():
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         assert (
             container.call(
                 ["sh", "-c", "echo $TEST_VAR"], env={"TEST_VAR": "1"}, capture_output=True
@@ -48,14 +48,16 @@ def test_environment():
 
 @pytest.mark.docker
 def test_cwd():
-    with DockerContainer(DEFAULT_IMAGE, cwd="/cibuildwheel/working_directory") as container:
+    with DockerContainer(
+        docker_image=DEFAULT_IMAGE, cwd="/cibuildwheel/working_directory"
+    ) as container:
         assert container.call(["pwd"], capture_output=True) == "/cibuildwheel/working_directory\n"
         assert container.call(["pwd"], capture_output=True, cwd="/opt") == "/opt\n"
 
 
 @pytest.mark.docker
 def test_container_removed():
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         docker_containers_listing = subprocess.run(
             "docker container ls",
             shell=True,
@@ -88,7 +90,7 @@ def test_large_environment():
         "d": "0" * long_env_var_length,
     }
 
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         # check the length of d
         assert (
             container.call(["sh", "-c", "echo ${#d}"], env=large_environment, capture_output=True)
@@ -98,7 +100,7 @@ def test_large_environment():
 
 @pytest.mark.docker
 def test_binary_output():
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         # note: the below embedded snippets are in python2
 
         # check that we can pass though arbitrary binary data without erroring
@@ -149,7 +151,7 @@ def test_binary_output():
 
 @pytest.mark.docker
 def test_file_operations(tmp_path: Path):
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         # test copying a file in
         test_binary_data = bytes(random.randrange(256) for _ in range(1000))
         original_test_file = tmp_path / "test.dat"
@@ -165,7 +167,7 @@ def test_file_operations(tmp_path: Path):
 
 @pytest.mark.docker
 def test_dir_operations(tmp_path: Path):
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         test_binary_data = bytes(random.randrange(256) for _ in range(1000))
         original_test_file = tmp_path / "test.dat"
         original_test_file.write_bytes(test_binary_data)
@@ -195,6 +197,6 @@ def test_dir_operations(tmp_path: Path):
 
 @pytest.mark.docker
 def test_environment_executor():
-    with DockerContainer(DEFAULT_IMAGE) as container:
+    with DockerContainer(docker_image=DEFAULT_IMAGE) as container:
         assignment = EnvironmentAssignment("TEST=$(echo 42)")
         assert assignment.evaluated_value({}, container.environment_executor) == "42"

unit_test/linux_build_steps_test.py

@@ -0,0 +1,70 @@
+import textwrap
+from pathlib import Path
+from pprint import pprint
+
+import cibuildwheel.docker_container
+import cibuildwheel.linux
+from cibuildwheel.options import Options
+
+from .utils import get_default_command_line_arguments
+
+
+def test_linux_container_split(tmp_path: Path, monkeypatch):
+    """
+    Tests splitting linux builds by docker image and before_all
+    """
+
+    args = get_default_command_line_arguments()
+    args.platform = "linux"
+
+    (tmp_path / "pyproject.toml").write_text(
+        textwrap.dedent(
+            """
+                [tool.cibuildwheel]
+                manylinux-x86_64-image = "normal_docker_image"
+                manylinux-i686-image = "normal_docker_image"
+                build = "*-manylinux_x86_64"
+                skip = "pp*"
+                archs = "x86_64 i686"
+
+                [[tool.cibuildwheel.overrides]]
+                select = "cp{38,39,310}-*"
+                manylinux-x86_64-image = "other_docker_image"
+                manylinux-i686-image = "other_docker_image"
+
+                [[tool.cibuildwheel.overrides]]
+                select = "cp39-*"
+                before-all = "echo 'a cp39-only command'"
+            """
+        )
+    )
+
+    monkeypatch.chdir(tmp_path)
+    options = Options("linux", command_line_arguments=args)
+
+    python_configurations = cibuildwheel.linux.get_python_configurations(
+        options.globals.build_selector, options.globals.architectures
+    )
+
+    build_steps = list(cibuildwheel.linux.get_build_steps(options, python_configurations))
+
+    # helper functions to extract test info
+    def identifiers(step):
+        return [c.identifier for c in step.platform_configs]
+
+    def before_alls(step):
+        return [options.build_options(c.identifier).before_all for c in step.platform_configs]
+
+    pprint(build_steps)
+
+    assert build_steps[0].docker_image == "normal_docker_image"
+    assert identifiers(build_steps[0]) == ["cp36-manylinux_x86_64", "cp37-manylinux_x86_64"]
+    assert before_alls(build_steps[0]) == ["", ""]
+
+    assert build_steps[1].docker_image == "other_docker_image"
+    assert identifiers(build_steps[1]) == ["cp38-manylinux_x86_64", "cp310-manylinux_x86_64"]
+    assert before_alls(build_steps[1]) == ["", ""]
+
+    assert build_steps[2].docker_image == "other_docker_image"
+    assert identifiers(build_steps[2]) == ["cp39-manylinux_x86_64"]
+    assert before_alls(build_steps[2]) == ["echo 'a cp39-only command'"]

unit_test/main_tests/conftest.py

@@ -15,9 +15,6 @@ class ArgsInterceptor:
         self.kwargs = kwargs
 
 
-MOCK_PACKAGE_DIR = Path("some_package_dir")
-
-
 @pytest.fixture(autouse=True)
 def mock_protection(monkeypatch):
     """
@@ -41,22 +38,8 @@ def mock_protection(monkeypatch):
 
 
 @pytest.fixture(autouse=True)
-def fake_package_dir(monkeypatch):
+def fake_package_dir_autouse(fake_package_dir):
-    """
+    pass
-    Monkey-patch enough for the main() function to run
-    """
-    real_path_exists = Path.exists
-
-    def mock_path_exists(path):
-        if path == MOCK_PACKAGE_DIR / "setup.py":
-            return True
-        else:
-            return real_path_exists(path)
-
-    args = ["cibuildwheel", str(MOCK_PACKAGE_DIR)]
-    monkeypatch.setattr(Path, "exists", mock_path_exists)
-    monkeypatch.setattr(sys, "argv", args)
-    return args
 
 
 @pytest.fixture(autouse=True)

unit_test/main_tests/main_options_test.py

@@ -3,10 +3,12 @@ from fnmatch import fnmatch
 from pathlib import Path
 
 import pytest
+import tomli
 
 from cibuildwheel.__main__ import main
 from cibuildwheel.environment import ParsedEnvironment
-from cibuildwheel.util import BuildSelector
+from cibuildwheel.options import BuildOptions, _get_pinned_docker_images
+from cibuildwheel.util import BuildSelector, resources_dir
 
 # CIBW_PLATFORM is tested in main_platform_test.py
 
@@ -18,13 +20,13 @@ def test_output_dir(platform, intercepted_build_args, monkeypatch):
 
     main()
 
-    assert intercepted_build_args.args[0].output_dir == OUTPUT_DIR
+    assert intercepted_build_args.args[0].globals.output_dir == OUTPUT_DIR
 
 
 def test_output_dir_default(platform, intercepted_build_args, monkeypatch):
     main()
 
-    assert intercepted_build_args.args[0].output_dir == Path("wheelhouse")
+    assert intercepted_build_args.args[0].globals.output_dir == Path("wheelhouse")
 
 
 @pytest.mark.parametrize("also_set_environment", [False, True])
@@ -37,7 +39,7 @@ def test_output_dir_argument(also_set_environment, platform, intercepted_build_a
 
     main()
 
-    assert intercepted_build_args.args[0].output_dir == OUTPUT_DIR
+    assert intercepted_build_args.args[0].globals.output_dir == OUTPUT_DIR
 
 
 def test_build_selector(platform, intercepted_build_args, monkeypatch, allow_empty):
@@ -49,7 +51,7 @@ def test_build_selector(platform, intercepted_build_args, monkeypatch, allow_emp
 
     main()
 
-    intercepted_build_selector = intercepted_build_args.args[0].build_selector
+    intercepted_build_selector = intercepted_build_args.args[0].globals.build_selector
     assert isinstance(intercepted_build_selector, BuildSelector)
     assert intercepted_build_selector("build24-this")
     assert not intercepted_build_selector("skip65-that")
@@ -97,10 +99,15 @@ def test_manylinux_images(
 
     main()
 
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+
     if platform == "linux":
-        assert fnmatch(intercepted_build_args.args[0].manylinux_images[architecture], full_image)
+        assert fnmatch(
+            build_options.manylinux_images[architecture],
+            full_image,
+        )
     else:
-        assert intercepted_build_args.args[0].manylinux_images is None
+        assert build_options.manylinux_images is None
 
 
 def get_default_repair_command(platform):
@@ -128,8 +135,10 @@ def test_repair_command(
 
     main()
 
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+
     expected_repair = repair_command or get_default_repair_command(platform)
-    assert intercepted_build_args.args[0].repair_command == expected_repair
+    assert build_options.repair_command == expected_repair
 
 
 @pytest.mark.parametrize(
@@ -147,7 +156,9 @@ def test_environment(environment, platform_specific, platform, intercepted_build
 
     main()
 
-    intercepted_environment = intercepted_build_args.args[0].environment
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+    intercepted_environment = build_options.environment
+
     assert isinstance(intercepted_environment, ParsedEnvironment)
     assert intercepted_environment.as_dictionary(prev_environment={}) == environment
 
@@ -166,7 +177,9 @@ def test_test_requires(
 
     main()
 
-    assert intercepted_build_args.args[0].test_requires == (test_requires or "").split()
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+
+    assert build_options.test_requires == (test_requires or "").split()
 
 
 @pytest.mark.parametrize("test_extras", [None, "extras"])
@@ -181,9 +194,9 @@ def test_test_extras(test_extras, platform_specific, platform, intercepted_build
 
     main()
 
-    assert intercepted_build_args.args[0].test_extras == (
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
-        "[" + test_extras + "]" if test_extras else ""
+
-    )
+    assert build_options.test_extras == ("[" + test_extras + "]" if test_extras else "")
 
 
 @pytest.mark.parametrize("test_command", [None, "test --command"])
@@ -200,7 +213,9 @@ def test_test_command(
 
     main()
 
-    assert intercepted_build_args.args[0].test_command == (test_command or "")
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+
+    assert build_options.test_command == (test_command or "")
 
 
 @pytest.mark.parametrize("before_build", [None, "before --build"])
@@ -217,7 +232,8 @@ def test_before_build(
 
     main()
 
-    assert intercepted_build_args.args[0].before_build == (before_build or "")
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+    assert build_options.before_build == (before_build or "")
 
 
 @pytest.mark.parametrize("build_verbosity", [None, 0, 2, -2, 4, -4])
@@ -233,9 +249,10 @@ def test_build_verbosity(
             monkeypatch.setenv("CIBW_BUILD_VERBOSITY", str(build_verbosity))
 
     main()
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
 
     expected_verbosity = max(-3, min(3, int(build_verbosity or 0)))
-    assert intercepted_build_args.args[0].build_verbosity == expected_verbosity
+    assert build_options.build_verbosity == expected_verbosity
 
 
 @pytest.mark.parametrize(
@@ -286,4 +303,36 @@ def test_before_all(before_all, platform_specific, platform, intercepted_build_a
 
     main()
 
-    assert intercepted_build_args.args[0].before_all == (before_all or "")
+    build_options = intercepted_build_args.args[0].build_options(identifier=None)
+
+    assert build_options.before_all == (before_all or "")
+
+
+def test_defaults(platform, intercepted_build_args):
+    main()
+
+    build_options: BuildOptions = intercepted_build_args.args[0].build_options(identifier=None)
+    defaults_config_path = resources_dir / "defaults.toml"
+    with defaults_config_path.open("rb") as f:
+        defaults_toml = tomli.load(f)
+
+    root_defaults = defaults_toml["tool"]["cibuildwheel"]
+    platform_defaults = defaults_toml["tool"]["cibuildwheel"][platform]
+
+    defaults = {}
+    defaults.update(root_defaults)
+    defaults.update(platform_defaults)
+
+    # test a few options
+    assert build_options.before_all == defaults["before-all"]
+    repair_wheel_default = defaults["repair-wheel-command"]
+    if isinstance(repair_wheel_default, list):
+        repair_wheel_default = " && ".join(repair_wheel_default)
+    assert build_options.repair_command == repair_wheel_default
+    assert build_options.build_frontend == defaults["build-frontend"]
+
+    if platform == "linux":
+        assert build_options.manylinux_images
+        pinned_images = _get_pinned_docker_images()
+        default_x86_64_image = pinned_images["x86_64"][defaults["manylinux-x86_64-image"]]
+        assert build_options.manylinux_images["x86_64"] == default_x86_64_image

unit_test/main_tests/main_platform_test.py

@@ -5,7 +5,7 @@ import pytest
 from cibuildwheel.__main__ import main
 from cibuildwheel.architecture import Architecture
 
-from .conftest import MOCK_PACKAGE_DIR
+from ..conftest import MOCK_PACKAGE_DIR
 
 
 def test_unknown_platform_non_ci(monkeypatch, capsys):
@@ -58,26 +58,29 @@ def test_platform_argument(platform, intercepted_build_args, monkeypatch):
 
     main()
 
-    assert intercepted_build_args.args[0].package_dir == MOCK_PACKAGE_DIR
+    options = intercepted_build_args.args[0]
+
+    assert options.globals.package_dir == MOCK_PACKAGE_DIR
 
 
 def test_platform_environment(platform, intercepted_build_args, monkeypatch):
     main()
+    options = intercepted_build_args.args[0]
 
-    assert intercepted_build_args.args[0].package_dir == MOCK_PACKAGE_DIR
+    assert options.globals.package_dir == MOCK_PACKAGE_DIR
 
 
 def test_archs_default(platform, intercepted_build_args, monkeypatch):
 
     main()
-    build_options = intercepted_build_args.args[0]
+    options = intercepted_build_args.args[0]
 
     if platform == "linux":
-        assert build_options.architectures == {Architecture.x86_64, Architecture.i686}
+        assert options.globals.architectures == {Architecture.x86_64, Architecture.i686}
     elif platform == "windows":
-        assert build_options.architectures == {Architecture.AMD64, Architecture.x86}
+        assert options.globals.architectures == {Architecture.AMD64, Architecture.x86}
     else:
-        assert build_options.architectures == {Architecture.x86_64}
+        assert options.globals.architectures == {Architecture.x86_64}
 
 
 @pytest.mark.parametrize("use_env_var", [False, True])
@@ -96,8 +99,8 @@ def test_archs_argument(platform, intercepted_build_args, monkeypatch, use_env_v
 
     else:
         main()
-        build_options = intercepted_build_args.args[0]
+        options = intercepted_build_args.args[0]
-        assert build_options.architectures == {Architecture.ppc64le}
+        assert options.globals.architectures == {Architecture.ppc64le}
 
 
 def test_archs_platform_specific(platform, intercepted_build_args, monkeypatch):
@@ -107,38 +110,38 @@ def test_archs_platform_specific(platform, intercepted_build_args, monkeypatch):
     monkeypatch.setenv("CIBW_ARCHS_MACOS", "x86_64")
 
     main()
-    build_options = intercepted_build_args.args[0]
+    options = intercepted_build_args.args[0]
 
     if platform == "linux":
-        assert build_options.architectures == {Architecture.ppc64le}
+        assert options.globals.architectures == {Architecture.ppc64le}
     elif platform == "windows":
-        assert build_options.architectures == {Architecture.x86}
+        assert options.globals.architectures == {Architecture.x86}
     elif platform == "macos":
-        assert build_options.architectures == {Architecture.x86_64}
+        assert options.globals.architectures == {Architecture.x86_64}
 
 
 def test_archs_platform_native(platform, intercepted_build_args, monkeypatch):
     monkeypatch.setenv("CIBW_ARCHS", "native")
 
     main()
-    build_options = intercepted_build_args.args[0]
+    options = intercepted_build_args.args[0]
 
     if platform in {"linux", "macos"}:
-        assert build_options.architectures == {Architecture.x86_64}
+        assert options.globals.architectures == {Architecture.x86_64}
     elif platform == "windows":
-        assert build_options.architectures == {Architecture.AMD64}
+        assert options.globals.architectures == {Architecture.AMD64}
 
 
 def test_archs_platform_auto64(platform, intercepted_build_args, monkeypatch):
     monkeypatch.setenv("CIBW_ARCHS", "auto64")
 
     main()
-    build_options = intercepted_build_args.args[0]
+    options = intercepted_build_args.args[0]
 
     if platform in {"linux", "macos"}:
-        assert build_options.architectures == {Architecture.x86_64}
+        assert options.globals.architectures == {Architecture.x86_64}
     elif platform == "windows":
-        assert build_options.architectures == {Architecture.AMD64}
+        assert options.globals.architectures == {Architecture.AMD64}
 
 
 def test_archs_platform_auto32(platform, intercepted_build_args, monkeypatch):
@@ -152,22 +155,22 @@ def test_archs_platform_auto32(platform, intercepted_build_args, monkeypatch):
     else:
         main()
 
-        build_options = intercepted_build_args.args[0]
+        options = intercepted_build_args.args[0]
 
         if platform == "linux":
-            assert build_options.architectures == {Architecture.i686}
+            assert options.globals.architectures == {Architecture.i686}
         elif platform == "windows":
-            assert build_options.architectures == {Architecture.x86}
+            assert options.globals.architectures == {Architecture.x86}
 
 
 def test_archs_platform_all(platform, intercepted_build_args, monkeypatch):
     monkeypatch.setenv("CIBW_ARCHS", "all")
 
     main()
-    build_options = intercepted_build_args.args[0]
+    options = intercepted_build_args.args[0]
 
     if platform == "linux":
-        assert build_options.architectures == {
+        assert options.globals.architectures == {
             Architecture.x86_64,
             Architecture.i686,
             Architecture.aarch64,
@@ -175,9 +178,9 @@ def test_archs_platform_all(platform, intercepted_build_args, monkeypatch):
             Architecture.s390x,
         }
     elif platform == "windows":
-        assert build_options.architectures == {Architecture.x86, Architecture.AMD64}
+        assert options.globals.architectures == {Architecture.x86, Architecture.AMD64}
     elif platform == "macos":
-        assert build_options.architectures == {
+        assert options.globals.architectures == {
             Architecture.x86_64,
             Architecture.arm64,
             Architecture.universal2,

unit_test/main_tests/main_requires_python_test.py

@@ -27,7 +27,8 @@ def test_no_override(platform, monkeypatch, intercepted_build_args):
 
     main()
 
-    intercepted_build_selector = intercepted_build_args.args[0].build_selector
+    options = intercepted_build_args.args[0]
+    intercepted_build_selector = options.globals.build_selector
 
     assert intercepted_build_selector("cp39-win32")
     assert intercepted_build_selector("cp36-win32")
@@ -40,7 +41,8 @@ def test_override_env(platform, monkeypatch, intercepted_build_args):
 
     main()
 
-    intercepted_build_selector = intercepted_build_args.args[0].build_selector
+    options = intercepted_build_args.args[0]
+    intercepted_build_selector = options.globals.build_selector
 
     assert intercepted_build_selector.requires_python == SpecifierSet(">=3.8")
 
@@ -61,7 +63,8 @@ def test_override_setup_cfg(platform, monkeypatch, intercepted_build_args, fake_
 
     main()
 
-    intercepted_build_selector = intercepted_build_args.args[0].build_selector
+    options = intercepted_build_args.args[0]
+    intercepted_build_selector = options.globals.build_selector
 
     assert intercepted_build_selector.requires_python == SpecifierSet(">=3.8")
 
@@ -82,7 +85,8 @@ def test_override_pyproject_toml(platform, monkeypatch, intercepted_build_args,
 
     main()
 
-    intercepted_build_selector = intercepted_build_args.args[0].build_selector
+    options = intercepted_build_args.args[0]
+    intercepted_build_selector = options.globals.build_selector
 
     assert intercepted_build_selector.requires_python == SpecifierSet(">=3.8")
 
@@ -107,7 +111,8 @@ def test_override_setup_py_simple(platform, monkeypatch, intercepted_build_args,
 
     main()
 
-    intercepted_build_selector = intercepted_build_args.args[0].build_selector
+    options = intercepted_build_args.args[0]
+    intercepted_build_selector = options.globals.build_selector
 
     assert intercepted_build_selector.requires_python == SpecifierSet(">=3.7")
 

unit_test/option_prepare_test.py

@@ -0,0 +1,169 @@
+import platform as platform_module
+import subprocess
+import sys
+from contextlib import contextmanager
+from pathlib import Path
+from typing import cast
+from unittest import mock
+
+import pytest
+
+from cibuildwheel import linux, util
+from cibuildwheel.__main__ import main
+
+ALL_IDS = {"cp36", "cp37", "cp38", "cp39", "cp310", "pp37"}
+
+
+@pytest.fixture
+def mock_build_docker(monkeypatch):
+    def fail_on_call(*args, **kwargs):
+        raise RuntimeError("This should never be called")
+
+    def ignore_call(*args, **kwargs):
+        pass
+
+    @contextmanager
+    def nullcontext(enter_result=None):
+        yield enter_result
+
+    def ignore_context_call(*args, **kwargs):
+        return nullcontext(kwargs)
+
+    monkeypatch.setenv("CIBW_PLATFORM", "linux")
+    monkeypatch.setattr(platform_module, "machine", lambda: "x86_64")
+
+    monkeypatch.setattr(subprocess, "Popen", fail_on_call)
+    monkeypatch.setattr(subprocess, "run", ignore_call)
+    monkeypatch.setattr(util, "download", fail_on_call)
+    monkeypatch.setattr("cibuildwheel.linux.DockerContainer", ignore_context_call)
+
+    monkeypatch.setattr("cibuildwheel.linux.build_on_docker", mock.Mock(spec=linux.build_on_docker))
+    monkeypatch.setattr("cibuildwheel.util.print_new_wheels", ignore_context_call)
+
+
+def test_build_default_launches(mock_build_docker, fake_package_dir, monkeypatch):
+    monkeypatch.setattr(sys, "argv", ["cibuildwheel", "--platform=linux"])
+
+    main()
+
+    build_on_docker = cast(mock.Mock, linux.build_on_docker)
+
+    assert build_on_docker.call_count == 4
+
+    # In Python 3.8+, this can be simplified to [0].kwargs
+    kwargs = build_on_docker.call_args_list[0][1]
+    assert "quay.io/pypa/manylinux2010_x86_64" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert not kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {f"{x}-manylinux_x86_64" for x in ALL_IDS}
+
+    kwargs = build_on_docker.call_args_list[1][1]
+    assert "quay.io/pypa/manylinux2010_i686" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {f"{x}-manylinux_i686" for x in ALL_IDS}
+
+    kwargs = build_on_docker.call_args_list[2][1]
+    assert "quay.io/pypa/musllinux_1_1_x86_64" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert not kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {
+        f"{x}-musllinux_x86_64" for x in ALL_IDS for x in ALL_IDS if "pp" not in x
+    }
+
+    kwargs = build_on_docker.call_args_list[3][1]
+    assert "quay.io/pypa/musllinux_1_1_i686" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {f"{x}-musllinux_i686" for x in ALL_IDS if "pp" not in x}
+
+
+def test_build_with_override_launches(mock_build_docker, monkeypatch, tmp_path):
+    pkg_dir = tmp_path / "cibw_package"
+    pkg_dir.mkdir()
+
+    cibw_toml = pkg_dir / "pyproject.toml"
+    cibw_toml.write_text(
+        """
+[tool.cibuildwheel]
+manylinux-x86_64-image = "manylinux2014"
+
+# Before Python 3.10, manylinux2010 is the most compatible
+[[tool.cibuildwheel.overrides]]
+select = "cp3?-*"
+manylinux-x86_64-image = "manylinux2010"
+manylinux-i686-image = "manylinux2010"
+
+[[tool.cibuildwheel.overrides]]
+select = "cp36-manylinux_x86_64"
+before-all = "true"
+"""
+    )
+
+    monkeypatch.chdir(pkg_dir)
+    monkeypatch.setattr(sys, "argv", ["cibuildwheel", "--platform=linux"])
+
+    main()
+
+    build_on_docker = cast(mock.Mock, linux.build_on_docker)
+
+    assert build_on_docker.call_count == 6
+
+    kwargs = build_on_docker.call_args_list[0][1]
+    assert "quay.io/pypa/manylinux2010_x86_64" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert not kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {"cp36-manylinux_x86_64"}
+    assert kwargs["options"].build_options("cp36-manylinux_x86_64").before_all == "true"
+
+    kwargs = build_on_docker.call_args_list[1][1]
+    assert "quay.io/pypa/manylinux2010_x86_64" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert not kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {f"{x}-manylinux_x86_64" for x in ALL_IDS - {"cp36", "cp310", "pp37"}}
+    assert kwargs["options"].build_options("cp37-manylinux_x86_64").before_all == ""
+
+    kwargs = build_on_docker.call_args_list[2][1]
+    assert "quay.io/pypa/manylinux2014_x86_64" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert not kwargs["docker"]["simulate_32_bit"]
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {"cp310-manylinux_x86_64", "pp37-manylinux_x86_64"}
+
+    kwargs = build_on_docker.call_args_list[3][1]
+    assert "quay.io/pypa/manylinux2010_i686" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {f"{x}-manylinux_i686" for x in ALL_IDS}
+
+    kwargs = build_on_docker.call_args_list[4][1]
+    assert "quay.io/pypa/musllinux_1_1_x86_64" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert not kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {
+        f"{x}-musllinux_x86_64" for x in ALL_IDS for x in ALL_IDS if "pp" not in x
+    }
+
+    kwargs = build_on_docker.call_args_list[5][1]
+    assert "quay.io/pypa/musllinux_1_1_i686" in kwargs["docker"]["docker_image"]
+    assert kwargs["docker"]["cwd"] == Path("/project")
+    assert kwargs["docker"]["simulate_32_bit"]
+
+    identifiers = {x.identifier for x in kwargs["platform_configs"]}
+    assert identifiers == {f"{x}-musllinux_i686" for x in ALL_IDS if "pp" not in x}

unit_test/options_test.py

@@ -0,0 +1,68 @@
+import platform as platform_module
+
+from cibuildwheel.__main__ import get_build_identifiers
+from cibuildwheel.environment import parse_environment
+from cibuildwheel.options import Options, _get_pinned_docker_images
+
+from .utils import get_default_command_line_arguments
+
+PYPROJECT_1 = """
+[tool.cibuildwheel]
+build = ["cp38*", "cp37*"]
+environment = {FOO="BAR"}
+
+test-command = "pyproject"
+
+manylinux-x86_64-image = "manylinux1"
+
+[tool.cibuildwheel.macos]
+test-requires = "else"
+
+[[tool.cibuildwheel.overrides]]
+select = "cp37*"
+test-command = "pyproject-override"
+manylinux-x86_64-image = "manylinux2014"
+"""
+
+
+def test_options_1(tmp_path, monkeypatch):
+    with tmp_path.joinpath("pyproject.toml").open("w") as f:
+        f.write(PYPROJECT_1)
+
+    args = get_default_command_line_arguments()
+    args.package_dir = str(tmp_path)
+
+    monkeypatch.setattr(platform_module, "machine", lambda: "x86_64")
+
+    options = Options(platform="linux", command_line_arguments=args)
+
+    identifiers = get_build_identifiers(
+        platform="linux",
+        build_selector=options.globals.build_selector,
+        architectures=options.globals.architectures,
+    )
+
+    override_display = """\
+test_command: 'pyproject'
+  cp37-manylinux_x86_64: 'pyproject-override'"""
+
+    print(options.summary(identifiers))
+
+    assert override_display in options.summary(identifiers)
+
+    default_build_options = options.build_options(identifier=None)
+
+    assert default_build_options.environment == parse_environment('FOO="BAR"')
+
+    all_pinned_docker_images = _get_pinned_docker_images()
+    pinned_x86_64_docker_image = all_pinned_docker_images["x86_64"]
+
+    local = options.build_options("cp38-manylinux_x86_64")
+    assert local.manylinux_images is not None
+    assert local.test_command == "pyproject"
+    assert local.manylinux_images["x86_64"] == pinned_x86_64_docker_image["manylinux1"]
+
+    local = options.build_options("cp37-manylinux_x86_64")
+    assert local.manylinux_images is not None
+    assert local.test_command == "pyproject-override"
+    assert local.manylinux_images["x86_64"] == pinned_x86_64_docker_image["manylinux2014"]

unit_test/options_toml_test.py

@@ -1,6 +1,8 @@
+from pathlib import Path
+
 import pytest
 
-from cibuildwheel.options import ConfigOptionError, ConfigOptions, _dig_first
+from cibuildwheel.options import ConfigOptionError, OptionsReader, _dig_first
 
 PYPROJECT_1 = """
 [tool.cibuildwheel]
@@ -28,39 +30,43 @@ def platform(request):
 
 @pytest.mark.parametrize("fname", ["pyproject.toml", "cibuildwheel.toml"])
 def test_simple_settings(tmp_path, platform, fname):
-    with tmp_path.joinpath(fname).open("w") as f:
+    config_file_path: Path = tmp_path / fname
-        f.write(PYPROJECT_1)
+    config_file_path.write_text(PYPROJECT_1)
 
-    options = ConfigOptions(tmp_path, f"{{package}}/{fname}", platform=platform)
+    options_reader = OptionsReader(config_file_path, platform=platform)
 
-    assert options("build", env_plat=False, sep=" ") == "cp39*"
+    assert options_reader.get("build", env_plat=False, sep=" ") == "cp39*"
 
-    assert options("test-command") == "pyproject"
+    assert options_reader.get("test-command") == "pyproject"
-    assert options("archs", sep=" ") == "auto"
+    assert options_reader.get("archs", sep=" ") == "auto"
     assert (
-        options("test-requires", sep=" ")
+        options_reader.get("test-requires", sep=" ")
         == {"windows": "something", "macos": "else", "linux": "other many"}[platform]
     )
 
     # Also testing options for support for both lists and tables
     assert (
-        options("environment", table={"item": '{k}="{v}"', "sep": " "}) == 'THING="OTHER" FOO="BAR"'
+        options_reader.get("environment", table={"item": '{k}="{v}"', "sep": " "})
-    )
-    assert (
-        options("environment", sep="x", table={"item": '{k}="{v}"', "sep": " "})
         == 'THING="OTHER" FOO="BAR"'
     )
-    assert options("test-extras", sep=",") == "one,two"
+    assert (
-    assert options("test-extras", sep=",", table={"item": '{k}="{v}"', "sep": " "}) == "one,two"
+        options_reader.get("environment", sep="x", table={"item": '{k}="{v}"', "sep": " "})
+        == 'THING="OTHER" FOO="BAR"'
+    )
+    assert options_reader.get("test-extras", sep=",") == "one,two"
+    assert (
+        options_reader.get("test-extras", sep=",", table={"item": '{k}="{v}"', "sep": " "})
+        == "one,two"
+    )
 
-    assert options("manylinux-x86_64-image") == "manylinux1"
+    assert options_reader.get("manylinux-x86_64-image") == "manylinux1"
-    assert options("manylinux-i686-image") == "manylinux2010"
+    assert options_reader.get("manylinux-i686-image") == "manylinux2010"
 
     with pytest.raises(ConfigOptionError):
-        options("environment", sep=" ")
+        options_reader.get("environment", sep=" ")
 
     with pytest.raises(ConfigOptionError):
-        options("test-extras", table={"item": '{k}="{v}"', "sep": " "})
+        options_reader.get("test-extras", table={"item": '{k}="{v}"', "sep": " "})
 
 
 def test_envvar_override(tmp_path, platform, monkeypatch):
@@ -70,44 +76,46 @@ def test_envvar_override(tmp_path, platform, monkeypatch):
     monkeypatch.setenv("CIBW_TEST_REQUIRES", "docs")
     monkeypatch.setenv("CIBW_TEST_REQUIRES_LINUX", "scod")
 
-    with tmp_path.joinpath("pyproject.toml").open("w") as f:
+    config_file_path: Path = tmp_path / "pyproject.toml"
-        f.write(PYPROJECT_1)
+    config_file_path.write_text(PYPROJECT_1)
 
-    options = ConfigOptions(tmp_path, platform=platform)
+    options_reader = OptionsReader(config_file_path, platform=platform)
 
-    assert options("archs", sep=" ") == "auto"
+    assert options_reader.get("archs", sep=" ") == "auto"
 
-    assert options("build", sep=" ") == "cp38*"
+    assert options_reader.get("build", sep=" ") == "cp38*"
-    assert options("manylinux-x86_64-image") == "manylinux2014"
+    assert options_reader.get("manylinux-x86_64-image") == "manylinux2014"
-    assert options("manylinux-i686-image") == "manylinux2010"
+    assert options_reader.get("manylinux-i686-image") == "manylinux2010"
 
     assert (
-        options("test-requires", sep=" ")
+        options_reader.get("test-requires", sep=" ")
         == {"windows": "docs", "macos": "docs", "linux": "scod"}[platform]
     )
-    assert options("test-command") == "mytest"
+    assert options_reader.get("test-command") == "mytest"
 
 
 def test_project_global_override_default_platform(tmp_path, platform):
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel]
 repair-wheel-command = "repair-project-global"
 """
     )
-    options = ConfigOptions(tmp_path, platform=platform)
+    options_reader = OptionsReader(pyproject_toml, platform=platform)
-    assert options("repair-wheel-command") == "repair-project-global"
+    assert options_reader.get("repair-wheel-command") == "repair-project-global"
 
 
 def test_env_global_override_default_platform(tmp_path, platform, monkeypatch):
     monkeypatch.setenv("CIBW_REPAIR_WHEEL_COMMAND", "repair-env-global")
-    options = ConfigOptions(tmp_path, platform=platform)
+    options_reader = OptionsReader(platform=platform)
-    assert options("repair-wheel-command") == "repair-env-global"
+    assert options_reader.get("repair-wheel-command") == "repair-env-global"
 
 
 def test_env_global_override_project_platform(tmp_path, platform, monkeypatch):
     monkeypatch.setenv("CIBW_REPAIR_WHEEL_COMMAND", "repair-env-global")
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel.linux]
 repair-wheel-command = "repair-project-linux"
@@ -117,12 +125,13 @@ repair-wheel-command = "repair-project-windows"
 repair-wheel-command = "repair-project-macos"
 """
     )
-    options = ConfigOptions(tmp_path, platform=platform)
+    options_reader = OptionsReader(pyproject_toml, platform=platform)
-    assert options("repair-wheel-command") == "repair-env-global"
+    assert options_reader.get("repair-wheel-command") == "repair-env-global"
 
 
 def test_global_platform_order(tmp_path, platform):
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel.linux]
 repair-wheel-command = "repair-project-linux"
@@ -134,14 +143,15 @@ repair-wheel-command = "repair-project-macos"
 repair-wheel-command = "repair-project-global"
 """
     )
-    options = ConfigOptions(tmp_path, platform=platform)
+    options_reader = OptionsReader(pyproject_toml, platform=platform)
-    assert options("repair-wheel-command") == f"repair-project-{platform}"
+    assert options_reader.get("repair-wheel-command") == f"repair-project-{platform}"
 
 
 def test_unexpected_key(tmp_path):
     # Note that platform contents are only checked when running
     # for that platform.
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel]
 repairs-wheel-command = "repair-project-linux"
@@ -149,49 +159,53 @@ repairs-wheel-command = "repair-project-linux"
     )
 
     with pytest.raises(ConfigOptionError):
-        ConfigOptions(tmp_path, platform="linux")
+        OptionsReader(pyproject_toml, platform="linux")
 
 
 def test_unexpected_table(tmp_path):
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel.linus]
 repair-wheel-command = "repair-project-linux"
 """
     )
     with pytest.raises(ConfigOptionError):
-        ConfigOptions(tmp_path, platform="linux")
+        OptionsReader(pyproject_toml, platform="linux")
 
 
 def test_unsupported_join(tmp_path):
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel]
 build = ["1", "2"]
 """
     )
-    options = ConfigOptions(tmp_path, platform="linux")
+    options_reader = OptionsReader(pyproject_toml, platform="linux")
 
-    assert "1, 2" == options("build", sep=", ")
+    assert "1, 2" == options_reader.get("build", sep=", ")
     with pytest.raises(ConfigOptionError):
-        options("build")
+        options_reader.get("build")
 
 
 def test_disallowed_a(tmp_path):
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel.windows]
 manylinux-x86_64-image = "manylinux1"
 """
     )
     disallow = {"windows": {"manylinux-x86_64-image"}}
-    ConfigOptions(tmp_path, platform="linux", disallow=disallow)
+    OptionsReader(pyproject_toml, platform="linux", disallow=disallow)
     with pytest.raises(ConfigOptionError):
-        ConfigOptions(tmp_path, platform="windows", disallow=disallow)
+        OptionsReader(pyproject_toml, platform="windows", disallow=disallow)
 
 
 def test_environment_override_empty(tmp_path, monkeypatch):
-    tmp_path.joinpath("pyproject.toml").write_text(
+    pyproject_toml = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(
         """
 [tool.cibuildwheel]
 manylinux-i686-image = "manylinux1"
@@ -202,15 +216,15 @@ manylinux-x86_64-image = ""
     monkeypatch.setenv("CIBW_MANYLINUX_I686_IMAGE", "")
     monkeypatch.setenv("CIBW_MANYLINUX_AARCH64_IMAGE", "manylinux1")
 
-    options = ConfigOptions(tmp_path, platform="linux")
+    options_reader = OptionsReader(pyproject_toml, platform="linux")
 
-    assert options("manylinux-x86_64-image") == ""
+    assert options_reader.get("manylinux-x86_64-image") == ""
-    assert options("manylinux-i686-image") == ""
+    assert options_reader.get("manylinux-i686-image") == ""
-    assert options("manylinux-aarch64-image") == "manylinux1"
+    assert options_reader.get("manylinux-aarch64-image") == "manylinux1"
 
-    assert options("manylinux-x86_64-image", ignore_empty=True) == "manylinux2010"
+    assert options_reader.get("manylinux-x86_64-image", ignore_empty=True) == "manylinux2010"
-    assert options("manylinux-i686-image", ignore_empty=True) == "manylinux1"
+    assert options_reader.get("manylinux-i686-image", ignore_empty=True) == "manylinux1"
-    assert options("manylinux-aarch64-image", ignore_empty=True) == "manylinux1"
+    assert options_reader.get("manylinux-aarch64-image", ignore_empty=True) == "manylinux1"
 
 
 @pytest.mark.parametrize("ignore_empty", (True, False))
@@ -246,3 +260,53 @@ def test_dig_first(ignore_empty):
             (d4, "other"),
             ignore_empty=ignore_empty,
         )
+
+
+PYPROJECT_2 = """
+[tool.cibuildwheel]
+build = ["cp38*", "cp37*"]
+environment = {FOO="BAR"}
+
+test-command = "pyproject"
+
+manylinux-x86_64-image = "manylinux1"
+
+[tool.cibuildwheel.macos]
+test-requires = "else"
+
+[[tool.cibuildwheel.overrides]]
+select = "cp37*"
+test-command = "pyproject-override"
+manylinux-x86_64-image = "manylinux2014"
+"""
+
+
+def test_pyproject_2(tmp_path, platform):
+    pyproject_toml: Path = tmp_path / "pyproject.toml"
+    pyproject_toml.write_text(PYPROJECT_2)
+
+    options_reader = OptionsReader(config_file_path=pyproject_toml, platform=platform)
+    assert options_reader.get("test-command") == "pyproject"
+
+    with options_reader.identifier("random"):
+        assert options_reader.get("test-command") == "pyproject"
+
+    with options_reader.identifier("cp37-something"):
+        assert options_reader.get("test-command") == "pyproject-override"
+
+
+def test_overrides_not_a_list(tmp_path, platform):
+    pyproject_toml: Path = tmp_path / "pyproject.toml"
+
+    pyproject_toml.write_text(
+        """\
+[tool.cibuildwheel]
+build = ["cp38*", "cp37*"]
+[tool.cibuildwheel.overrides]
+select = "cp37*"
+test-command = "pyproject-override"
+"""
+    )
+
+    with pytest.raises(ConfigOptionError):
+        OptionsReader(config_file_path=pyproject_toml, platform=platform)

unit_test/utils.py

@@ -0,0 +1,16 @@
+from cibuildwheel.options import CommandLineArguments
+
+
+def get_default_command_line_arguments() -> CommandLineArguments:
+    defaults = CommandLineArguments()
+
+    defaults.platform = "auto"
+    defaults.allow_empty = False
+    defaults.archs = None
+    defaults.config_file = None
+    defaults.output_dir = None
+    defaults.package_dir = "."
+    defaults.prerelease_pythons = False
+    defaults.print_build_identifiers = False
+
+    return defaults