Bump version: v1.5.5

Fix cwd in Linux docker images

.github/workflows/test.yml

@@ -17,6 +17,7 @@ jobs:
       matrix:
         os: [ubuntu-18.04, windows-latest, macos-latest]
         python_version: ['3.7']
+    timeout-minutes: 180
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-python@v2

README.md

@@ -79,7 +79,7 @@ env:
     # Note: TWINE_PASSWORD is set to a PyPI API token in Travis settings
 
 install:
-  - python3 -m pip install cibuildwheel==1.5.0
+  - python3 -m pip install cibuildwheel==1.5.5
 
 script:
   # build the wheels, put them into './wheelhouse'
@@ -94,7 +94,7 @@ after_success:
     fi
 ```
 
-For more information, including how to build on Appveyor, Azure, CircleCI, check out the [documentation](https://cibuildwheel.readthedocs.org) and also check out [the examples](https://github.com/joerick/cibuildwheel/tree/master/examples).
+For more information, including how to build on GitHub Actions, Appveyor, Azure Pipelines, or CircleCI, check out the [documentation](https://cibuildwheel.readthedocs.org) and the [examples](https://github.com/joerick/cibuildwheel/tree/master/examples).
 
 Options
 -------
@@ -152,6 +152,44 @@ This is similar to static linking, so it might have some licence implications. C
 Changelog
 =========
 
+### 1.5.5
+
+_22 July 2020_
+
+- 🐛 Fix a bug that would cause command substitutions in CIBW_ENVIRONMENT to
+  produce no output on Linux (#411)
+- 🐛 Fix regression (introduced in 1.5.3) which caused BEFORE_BUILD and
+  BEFORE_ALL to be executed in the wrong directory (#410)
+
+### 1.5.4
+
+_19 June 2020_
+
+- 🐛 Fix a bug that would cause command substitutions in CIBW_ENVIRONMENT
+  variables to not interpret quotes in commands correctly (#406, #408)
+
+### 1.5.3
+
+_19 July 2020_
+
+- 🛠 Update CPython 3.8 to 3.8.3 (#405)
+- 🛠 Internal refactoring of Linux build, to move control flow into Python (#386)
+
+### 1.5.2
+
+_8 July 2020_
+
+- 🐛 Fix an issue on Windows where pyproject.toml would cause an error when
+  some requirements formats were used. (#401)
+- 🛠 Update CPython 3.7 to 3.7.8 (#394)
+
+### 1.5.1
+
+_25 June 2020_
+
+- 🐛 Fix "OSError: [WinError 17] The system cannot move the file to a different
+  disk drive" on Github Actions (#388, #389)
+
 ### 1.5.0
 
 _24 June 2020_

azure-pipelines.yml

@@ -21,6 +21,7 @@ jobs:
 
 - job: windows_36
   pool: {vmImage: 'vs2017-win2016'}
+  timeoutInMinutes: 180
   steps:
     - task: UsePythonVersion@0
       inputs:
@@ -33,6 +34,7 @@ jobs:
 
 - job: windows_38
   pool: {vmImage: 'vs2017-win2016'}
+  timeoutInMinutes: 180
   steps:
     - task: UsePythonVersion@0
       inputs:

bin/run_tests.py

@@ -10,7 +10,11 @@ if __name__ == '__main__':
     os.chdir(Path(__file__).resolve().parents[1])
 
     # run the unit tests
-    subprocess.check_call([sys.executable, '-m', 'pytest', 'unit_test'])
+    unit_test_args = [sys.executable, '-m', 'pytest', 'unit_test']
+    # run the docker unit tests only on Linux
+    if sys.platform.startswith('linux'):
+        unit_test_args += ['--run-docker']
+    subprocess.check_call(unit_test_args)
 
     # run the integration tests
     subprocess.check_call([sys.executable, '-m', 'pytest', '-x', '--durations', '0', 'test'])

cibuildwheel/__init__.py

@@ -1 +1 @@
-__version__ = '1.5.0'
+__version__ = '1.5.5'

cibuildwheel/bashlex_eval.py

@@ -1,17 +1,23 @@
-import shlex
 import subprocess
-
+from typing import Callable, Dict, List, NamedTuple, Optional, Sequence
-from typing import Dict, NamedTuple
 
 import bashlex  # type: ignore
 
+# a function that takes a command and the environment, and returns the result
+EnvironmentExecutor = Callable[[List[str], Dict[str, str]], str]
+
+
+def local_environment_executor(command: List[str], env: Dict[str, str]) -> str:
+    return subprocess.check_output(command, env=env, universal_newlines=True)
+
 
 class NodeExecutionContext(NamedTuple):
     environment: Dict[str, str]
     input: str
+    executor: EnvironmentExecutor
 
 
-def evaluate(value: str, environment: Dict[str, str]) -> str:
+def evaluate(value: str, environment: Dict[str, str], executor: Optional[EnvironmentExecutor] = None) -> str:
     if not value:
         # empty string evaluates to empty string
         # (but trips up bashlex)
@@ -26,7 +32,7 @@ def evaluate(value: str, environment: Dict[str, str]) -> str:
 
     return evaluate_node(
         value_word_node,
-        context=NodeExecutionContext(environment=environment, input=value)
+        context=NodeExecutionContext(environment=environment, input=value, executor=executor or local_environment_executor)
     )
 
 
@@ -34,40 +40,64 @@ def evaluate_node(node: bashlex.ast.node, context: NodeExecutionContext) -> str:
     if node.kind == 'word':
         return evaluate_word_node(node, context=context)
     elif node.kind == 'commandsubstitution':
-        return evaluate_command_node(node.command, context=context)
+        node_result = evaluate_command_node(node.command, context=context)
+        # bash removes training newlines in command substitution
+        return node_result.rstrip()
     elif node.kind == 'parameter':
         return evaluate_parameter_node(node, context=context)
     else:
-        raise ValueError(f'Unsupported bash construct: "{node.word}"')
+        raise ValueError(f'Unsupported bash construct: "{node.kind}"')
 
 
 def evaluate_word_node(node: bashlex.ast.node, context: NodeExecutionContext) -> str:
-    word_start = node.pos[0]
+    value = node.word
-    word_end = node.pos[1]
-    word_string = context.input[word_start:word_end]
-    letters = list(word_string)
 
     for part in node.parts:
-        part_start = part.pos[0] - word_start
+        part_string = context.input[part.pos[0]:part.pos[1]]
-        part_end = part.pos[1] - word_start
+        part_value = evaluate_node(part, context=context)
 
-        # Set all the characters in the part to None
+        if part_string not in value:
-        for i in range(part_start, part_end):
+            raise RuntimeError(
-            letters[i] = ''
+                'bash parse failed. part "{}" not found in "{}". Word was "{}". Full input was "{}"'.format(
+                    part_string, value, node.word, context.input,
+                )
+            )
 
-        letters[part_start] = evaluate_node(part, context=context)
+        value = value.replace(part_string, part_value, 1)
 
-    # remove the None letters and concat
+    return value
-    value = ''.join(letters)
-
-    # apply bash-like quotes/whitespace treatment
-    return ' '.join(word.strip() for word in shlex.split(value))
 
 
 def evaluate_command_node(node: bashlex.ast.node, context: NodeExecutionContext) -> str:
-    words = [evaluate_node(part, context=context) for part in node.parts]
+    if any(n.kind == 'operator' for n in node.parts):
-    command = ' '.join(words)
+        return evaluate_nodes_as_compound_command(node.parts, context=context)
-    return subprocess.check_output(shlex.split(command), env=context.environment, universal_newlines=True)
+    else:
+        return evaluate_nodes_as_simple_command(node.parts, context=context)
+
+
+def evaluate_nodes_as_compound_command(nodes: Sequence[bashlex.ast.node], context: NodeExecutionContext) -> str:
+    # bashlex doesn't support any operators besides ';' inside command
+    # substitutions, so we only need to handle that case. We do so assuming
+    # that `set -o errexit` is on, because it's easier to code!
+
+    result = ''
+    for node in nodes:
+        if node.kind == 'command':
+            result += evaluate_command_node(node, context=context)
+        elif node.kind == 'operator':
+            if node.op == ';':
+                pass
+            else:
+                raise ValueError(f'Unsupported bash operator: "{node.op}"')
+        else:
+            raise ValueError(f'Unsupported bash node in compound command: "{node.kind}"')
+
+    return result
+
+
+def evaluate_nodes_as_simple_command(nodes: List[bashlex.ast.node], context: NodeExecutionContext):
+    command = [evaluate_node(part, context=context) for part in nodes]
+    return context.executor(command, context.environment)
 
 
 def evaluate_parameter_node(node: bashlex.ast.node, context: NodeExecutionContext) -> str:

cibuildwheel/docker_container.py

@@ -0,0 +1,192 @@
+import io
+import json
+import os
+import shlex
+import subprocess
+import sys
+import uuid
+from os import PathLike
+from pathlib import Path, PurePath
+from typing import IO, Dict, List, Optional, Sequence, Union
+
+
+class DockerContainer:
+    '''
+    An object that represents a running Docker container.
+
+    Intended for use as a context manager e.g.
+    `with DockerContainer('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
+    back to cibuildwheel.
+    '''
+    UTILITY_PYTHON = '/opt/python/cp38-cp38/bin/python'
+
+    process: subprocess.Popen
+    bash_stdin: IO[bytes]
+    bash_stdout: IO[bytes]
+
+    def __init__(self, docker_image: str, simulate_32_bit: bool = False, cwd: Optional[Union[str, PathLike]] = None):
+        self.docker_image = docker_image
+        self.simulate_32_bit = simulate_32_bit
+        self.cwd = cwd
+
+    def __enter__(self) -> 'DockerContainer':
+        self.name = f'cibuildwheel-{uuid.uuid4()}'
+        cwd_args = ['-w', str(self.cwd)] if self.cwd else []
+        shell_args = ['linux32', '/bin/bash'] if self.simulate_32_bit else ['/bin/bash']
+        subprocess.run(
+            [
+                'docker', 'create',
+                '--env', 'CIBUILDWHEEL',
+                '--name', self.name,
+                '-i',
+                '-v', '/:/host',  # ignored on CircleCI
+                *cwd_args,
+                self.docker_image,
+                *shell_args
+            ],
+            check=True,
+        )
+        self.process = subprocess.Popen(
+            [
+                'docker', 'start',
+                '--attach', '--interactive',
+                self.name,
+            ],
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+        )
+
+        assert self.process.stdin and self.process.stdout
+        self.bash_stdin = self.process.stdin
+        self.bash_stdout = self.process.stdout
+
+        # run a noop command to block until the container is responding
+        self.call(['/bin/true'])
+
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.bash_stdin.close()
+        self.process.terminate()
+        self.process.wait()
+
+        subprocess.run(['docker', 'rm', '--force', '-v', self.name])
+        self.name = None
+
+    def copy_into(self, from_path: Path, to_path: PurePath) -> None:
+        # `docker cp` causes 'no space left on device' error when
+        # a container is running and the host filesystem is
+        # mounted. https://github.com/moby/moby/issues/38995
+        # Use `docker exec` instead.
+
+        if from_path.is_dir():
+            self.call(['mkdir', '-p', to_path])
+            subprocess.run(
+                f'tar cf - . | docker exec -i {self.name} tar -xC {shell_quote(to_path)} -f -',
+                shell=True,
+                check=True,
+                cwd=from_path)
+        else:
+            subprocess.run(
+                f'cat {shell_quote(from_path)} | docker exec -i {self.name} sh -c "cat > {shell_quote(to_path)}"',
+                shell=True,
+                check=True)
+
+    def copy_out(self, from_path: PurePath, to_path: Path) -> None:
+        # note: we assume from_path is a dir
+        to_path.mkdir(parents=True, exist_ok=True)
+
+        subprocess.run(
+            f'docker exec -i {self.name} tar -cC {shell_quote(from_path)} -f - . | tar -xf -',
+            shell=True,
+            check=True,
+            cwd=to_path
+        )
+
+    def glob(self, path: PurePath, pattern: str) -> List[PurePath]:
+        glob_pattern = os.path.join(str(path), pattern)
+
+        path_strs = json.loads(self.call([
+            self.UTILITY_PYTHON,
+            '-c',
+            f'import sys, json, glob; json.dump(glob.glob({glob_pattern!r}), sys.stdout)'
+        ], capture_output=True))
+
+        return [PurePath(p) for p in path_strs]
+
+    def call(self, args: Sequence[Union[str, PathLike]], env: Dict[str, str] = {},
+             capture_output=False, cwd: Optional[Union[str, PathLike]] = None) -> str:
+        chdir = f'cd {cwd}' if cwd else ''
+        env_assignments = ' '.join(f'{shlex.quote(k)}={shlex.quote(v)}'
+                                   for k, v in env.items())
+        command = ' '.join(shlex.quote(str(a)) for a in args)
+        end_of_message = str(uuid.uuid4())
+
+        # log the command we're executing
+        print(f'    + {command}')
+
+        # Write a command to the remote shell. First we change the
+        # cwd, if that's required. Then, we use the `env` utility to run
+        # `command` inside the specified environment. We use `env` because it
+        # can cope with spaces and strange characters in the name or value.
+        # Finally, the remote shell is told to write a footer - this will show
+        # up in the output so we know when to stop reading, and will include
+        # the returncode of `command`.
+        self.bash_stdin.write(bytes(f'''(
+            {chdir}
+            env {env_assignments} {command}
+            printf "%04d%s\n" $? {end_of_message}
+        )
+        ''', encoding='utf8', errors='surrogateescape'))
+        self.bash_stdin.flush()
+
+        if capture_output:
+            output_io: IO[bytes] = io.BytesIO()
+        else:
+            output_io = sys.stdout.buffer
+
+        while True:
+            line = self.bash_stdout.readline()
+
+            if line.endswith(b'%s\n' % (bytes(end_of_message, encoding='utf8'))):
+                footer_offset = (
+                    len(line)
+                    - 1  # newline character
+                    - len(end_of_message)  # delimiter
+                    - 4  # 4 returncode decimals
+                )
+                returncode_str = line[footer_offset:footer_offset+4]
+                returncode = int(returncode_str)
+                # add the last line to output, without the footer
+                output_io.write(line[0:footer_offset])
+                break
+            else:
+                output_io.write(line)
+
+        if isinstance(output_io, io.BytesIO):
+            output = str(output_io.getvalue(), encoding='utf8', errors='surrogateescape')
+        else:
+            output = ''
+
+        if returncode != 0:
+            raise subprocess.CalledProcessError(returncode, args, output)
+
+        return output
+
+    def get_environment(self) -> Dict[str, str]:
+        return json.loads(self.call([
+            self.UTILITY_PYTHON,
+            '-c',
+            'import sys, json, os; json.dump(os.environ.copy(), sys.stdout)'
+        ], capture_output=True))
+
+    def environment_executor(self, command: List[str], environment: Dict[str, str]) -> str:
+        # used as an EnvironmentExecutor to evaluate commands and capture output
+        return self.call(command, env=environment, capture_output=True)
+
+
+def shell_quote(path: PurePath) -> str:
+    return shlex.quote(str(path))

cibuildwheel/environment.py

@@ -1,6 +1,6 @@
 import bashlex  # type: ignore
 
-from typing import Dict, List, Mapping
+from typing import Dict, List, Mapping, Optional
 
 from . import bashlex_eval
 
@@ -46,9 +46,9 @@ class EnvironmentAssignment:
         self.name = name
         self.value = value
 
-    def evaluated_value(self, environment: Dict[str, str]) -> str:
+    def evaluated_value(self, environment: Dict[str, str], executor: Optional[bashlex_eval.EnvironmentExecutor] = None) -> str:
         '''Returns the value of this assignment, as evaluated in the environment'''
-        return bashlex_eval.evaluate(self.value, environment=environment)
+        return bashlex_eval.evaluate(self.value, environment=environment, executor=executor)
 
     def as_shell_assignment(self) -> str:
         return f'export {self.name}={self.value}'
@@ -61,11 +61,13 @@ class ParsedEnvironment:
     def __init__(self, assignments: List[EnvironmentAssignment]):
         self.assignments = assignments
 
-    def as_dictionary(self, prev_environment: Mapping[str, str]) -> Dict[str, str]:
+    def as_dictionary(self,
+                      prev_environment: Mapping[str, str],
+                      executor: Optional[bashlex_eval.EnvironmentExecutor] = None) -> Dict[str, str]:
         environment = dict(**prev_environment)
 
         for assignment in self.assignments:
-            value = assignment.evaluated_value(environment=environment)
+            value = assignment.evaluated_value(environment=environment, executor=executor)
             environment[assignment.name] = value
 
         return environment

cibuildwheel/linux.py

@@ -1,27 +1,14 @@
-import os
 import platform
-import shlex
 import subprocess
 import sys
 import textwrap
-import uuid
+from os import PathLike
 from pathlib import Path, PurePath
+from typing import List, NamedTuple, Union
 
-from typing import List, NamedTuple, Optional, Union
+from .docker_container import DockerContainer
-
+from .util import (BuildOptions, BuildSelector,
-from .util import (
+                   get_build_verbosity_extra_flags, prepare_command)
-    BuildOptions,
-    BuildSelector,
-    get_build_verbosity_extra_flags,
-    prepare_command,
-)
-
-
-def call(args: List[str], input: Optional[Union[str, bytes]] = None, universal_newlines: bool = False) -> None:
-    print('+ ' + ' '.join(shlex.quote(a) for a in args))
-    subprocess.run(
-        args, input=input, universal_newlines=universal_newlines, check=True
-    )
 
 
 def matches_platform(identifier: str) -> bool:
@@ -48,37 +35,41 @@ def matches_platform(identifier: str) -> bool:
 class PythonConfiguration(NamedTuple):
     version: str
     identifier: str
-    path: str
+    path_str: str
+
+    @property
+    def path(self):
+        return PurePath(self.path_str)
 
 
 def get_python_configurations(build_selector: BuildSelector) -> List[PythonConfiguration]:
     python_configurations = [
-        PythonConfiguration(version='2.7', identifier='cp27-manylinux_x86_64', path='/opt/python/cp27-cp27m'),
+        PythonConfiguration(version='2.7', identifier='cp27-manylinux_x86_64', path_str='/opt/python/cp27-cp27m'),
-        PythonConfiguration(version='2.7', identifier='cp27-manylinux_x86_64', path='/opt/python/cp27-cp27mu'),
+        PythonConfiguration(version='2.7', identifier='cp27-manylinux_x86_64', path_str='/opt/python/cp27-cp27mu'),
-        PythonConfiguration(version='3.5', identifier='cp35-manylinux_x86_64', path='/opt/python/cp35-cp35m'),
+        PythonConfiguration(version='3.5', identifier='cp35-manylinux_x86_64', path_str='/opt/python/cp35-cp35m'),
-        PythonConfiguration(version='3.6', identifier='cp36-manylinux_x86_64', path='/opt/python/cp36-cp36m'),
+        PythonConfiguration(version='3.6', identifier='cp36-manylinux_x86_64', path_str='/opt/python/cp36-cp36m'),
-        PythonConfiguration(version='3.7', identifier='cp37-manylinux_x86_64', path='/opt/python/cp37-cp37m'),
+        PythonConfiguration(version='3.7', identifier='cp37-manylinux_x86_64', path_str='/opt/python/cp37-cp37m'),
-        PythonConfiguration(version='3.8', identifier='cp38-manylinux_x86_64', path='/opt/python/cp38-cp38'),
+        PythonConfiguration(version='3.8', identifier='cp38-manylinux_x86_64', path_str='/opt/python/cp38-cp38'),
-        PythonConfiguration(version='2.7', identifier='cp27-manylinux_i686', path='/opt/python/cp27-cp27m'),
+        PythonConfiguration(version='2.7', identifier='cp27-manylinux_i686', path_str='/opt/python/cp27-cp27m'),
-        PythonConfiguration(version='2.7', identifier='cp27-manylinux_i686', path='/opt/python/cp27-cp27mu'),
+        PythonConfiguration(version='2.7', identifier='cp27-manylinux_i686', path_str='/opt/python/cp27-cp27mu'),
-        PythonConfiguration(version='3.5', identifier='cp35-manylinux_i686', path='/opt/python/cp35-cp35m'),
+        PythonConfiguration(version='3.5', identifier='cp35-manylinux_i686', path_str='/opt/python/cp35-cp35m'),
-        PythonConfiguration(version='3.6', identifier='cp36-manylinux_i686', path='/opt/python/cp36-cp36m'),
+        PythonConfiguration(version='3.6', identifier='cp36-manylinux_i686', path_str='/opt/python/cp36-cp36m'),
-        PythonConfiguration(version='3.7', identifier='cp37-manylinux_i686', path='/opt/python/cp37-cp37m'),
+        PythonConfiguration(version='3.7', identifier='cp37-manylinux_i686', path_str='/opt/python/cp37-cp37m'),
-        PythonConfiguration(version='3.8', identifier='cp38-manylinux_i686', path='/opt/python/cp38-cp38'),
+        PythonConfiguration(version='3.8', identifier='cp38-manylinux_i686', path_str='/opt/python/cp38-cp38'),
-        PythonConfiguration(version='2.7', identifier='pp27-manylinux_x86_64', path='/opt/python/pp27-pypy_73'),
+        PythonConfiguration(version='2.7', identifier='pp27-manylinux_x86_64', path_str='/opt/python/pp27-pypy_73'),
-        PythonConfiguration(version='3.6', identifier='pp36-manylinux_x86_64', path='/opt/python/pp36-pypy36_pp73'),
+        PythonConfiguration(version='3.6', identifier='pp36-manylinux_x86_64', path_str='/opt/python/pp36-pypy36_pp73'),
-        PythonConfiguration(version='3.5', identifier='cp35-manylinux_aarch64', path='/opt/python/cp35-cp35m'),
+        PythonConfiguration(version='3.5', identifier='cp35-manylinux_aarch64', path_str='/opt/python/cp35-cp35m'),
-        PythonConfiguration(version='3.6', identifier='cp36-manylinux_aarch64', path='/opt/python/cp36-cp36m'),
+        PythonConfiguration(version='3.6', identifier='cp36-manylinux_aarch64', path_str='/opt/python/cp36-cp36m'),
-        PythonConfiguration(version='3.7', identifier='cp37-manylinux_aarch64', path='/opt/python/cp37-cp37m'),
+        PythonConfiguration(version='3.7', identifier='cp37-manylinux_aarch64', path_str='/opt/python/cp37-cp37m'),
-        PythonConfiguration(version='3.8', identifier='cp38-manylinux_aarch64', path='/opt/python/cp38-cp38'),
+        PythonConfiguration(version='3.8', identifier='cp38-manylinux_aarch64', path_str='/opt/python/cp38-cp38'),
-        PythonConfiguration(version='3.5', identifier='cp35-manylinux_ppc64le', path='/opt/python/cp35-cp35m'),
+        PythonConfiguration(version='3.5', identifier='cp35-manylinux_ppc64le', path_str='/opt/python/cp35-cp35m'),
-        PythonConfiguration(version='3.6', identifier='cp36-manylinux_ppc64le', path='/opt/python/cp36-cp36m'),
+        PythonConfiguration(version='3.6', identifier='cp36-manylinux_ppc64le', path_str='/opt/python/cp36-cp36m'),
-        PythonConfiguration(version='3.7', identifier='cp37-manylinux_ppc64le', path='/opt/python/cp37-cp37m'),
+        PythonConfiguration(version='3.7', identifier='cp37-manylinux_ppc64le', path_str='/opt/python/cp37-cp37m'),
-        PythonConfiguration(version='3.8', identifier='cp38-manylinux_ppc64le', path='/opt/python/cp38-cp38'),
+        PythonConfiguration(version='3.8', identifier='cp38-manylinux_ppc64le', path_str='/opt/python/cp38-cp38'),
-        PythonConfiguration(version='3.5', identifier='cp35-manylinux_s390x', path='/opt/python/cp35-cp35m'),
+        PythonConfiguration(version='3.5', identifier='cp35-manylinux_s390x', path_str='/opt/python/cp35-cp35m'),
-        PythonConfiguration(version='3.6', identifier='cp36-manylinux_s390x', path='/opt/python/cp36-cp36m'),
+        PythonConfiguration(version='3.6', identifier='cp36-manylinux_s390x', path_str='/opt/python/cp36-cp36m'),
-        PythonConfiguration(version='3.7', identifier='cp37-manylinux_s390x', path='/opt/python/cp37-cp37m'),
+        PythonConfiguration(version='3.7', identifier='cp37-manylinux_s390x', path_str='/opt/python/cp37-cp37m'),
-        PythonConfiguration(version='3.8', identifier='cp38-manylinux_s390x', path='/opt/python/cp38-cp38'),
+        PythonConfiguration(version='3.8', identifier='cp38-manylinux_s390x', path_str='/opt/python/cp38-cp38'),
     ]
     # skip builds as required
     return [c for c in python_configurations if matches_platform(c.identifier) and build_selector(c.identifier)]
@@ -111,133 +102,99 @@ def build(options: BuildOptions) -> None:
         raise Exception('package_dir must be inside the working directory')
 
     container_package_dir = PurePath('/project') / abs_package_dir.relative_to(cwd)
+    container_output_dir = PurePath('/output')
 
     for implementation, platform_tag, docker_image in platforms:
         platform_configs = [c for c in python_configurations if c.identifier.startswith(implementation) and c.identifier.endswith(platform_tag)]
         if not platform_configs:
             continue
 
-        shell_cmd = ['linux32', '/bin/bash'] if platform_tag.endswith("i686") else ['/bin/bash']
-
-        container_name = f'cibuildwheel-{uuid.uuid4()}'
-        call(['docker', 'create',
-              '--env', 'CIBUILDWHEEL',
-              '--name', container_name,
-              '-i',
-              '-v', '/:/host',  # ignored on CircleCI
-              docker_image,
-              '/bin/bash'])
-
         try:
-            call(['docker', 'cp', '.', container_name + ':/project'])
+            with DockerContainer(docker_image, simulate_32_bit=platform_tag.endswith('i686'), cwd='/project') as docker:
-
+                docker.copy_into(Path.cwd(), PurePath('/project'))
-            call(['docker', 'start', container_name])
 
                 if options.before_all:
-                call(
+                    env = docker.get_environment()
-                    ['docker', 'exec', '-i', container_name] + shell_cmd,
+                    env['PATH'] = f'/opt/python/cp38-cp38:{env["PATH"]}'
-                    universal_newlines=True,
+                    env = options.environment.as_dictionary(env, executor=docker.environment_executor)
-                    input='''
-                        PS4='    + '
 
-                        set -o errexit
+                    before_all_prepared = prepare_command(options.before_all, project='/project', package=container_package_dir)
-                        set -o xtrace
+                    docker.call(['sh', '-c', before_all_prepared], env=env)
-
-                        # add a modern Python interpreter to PATH so it can be used by BEFORE_ALL
-                        # commands
-                        export PATH=/opt/python/cp38-cp38:$PATH
-
-                        {environment_exports}
-
-                        sh -c {before_all}
-
-                    '''.format(
-                        environment_exports='\n'.join(options.environment.as_shell_commands()),
-                        before_all=shlex.quote(prepare_command(options.before_all, project='/project', package=container_package_dir))
-                    )
-                )
 
                 for config in platform_configs:
+                    dependency_constraint_flags: List[Union[str, PathLike]] = []
+
                     if options.dependency_constraints:
                         constraints_file = options.dependency_constraints.get_for_python_version(config.version)
+                        container_constraints_file = PurePath('/constraints.txt')
 
-                    # `docker cp` causes 'no space left on device' error when
+                        docker.copy_into(constraints_file, container_constraints_file)
-                    # a container is running and the host filesystem is
+                        dependency_constraint_flags = ['-c', container_constraints_file]
-                    # mounted. https://github.com/moby/moby/issues/38995
-                    # Use `docker exec` instead.
-                    with open(constraints_file, 'rb') as f:
-                        call(
-                            ['docker', 'exec', '-i', container_name, 'sh', '-c', 'cat > /constraints.txt'],
-                            input=f.read(),
-                        )
 
-                call(
+                    env = docker.get_environment()
-                    ['docker', 'exec', '-i', container_name] + shell_cmd,
-                    universal_newlines=True,
-                    input='''
-                        # give xtrace output an extra level of indent inside docker
-                        PS4='    + '
 
-                        set -o errexit
+                    # put this config's python top of the list
-                        set -o xtrace
+                    python_bin = config.path / 'bin'
-                        mkdir -p /output
+                    env['PATH'] = f'{python_bin}:{env["PATH"]}'
-                        cd /project
 
-                        PYBIN="{config_python_bin}"
+                    env = options.environment.as_dictionary(env, executor=docker.environment_executor)
 
-                        export PATH="$PYBIN:$PATH"
+                    # check config python and pip are still on PATH
-                        {environment_exports}
+                    which_python = docker.call(['which', 'python'], env=env, capture_output=True).strip()
+                    if PurePath(which_python) != python_bin / 'python':
+                        print("cibuildwheel: python available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert python above it.", file=sys.stderr)
+                        exit(1)
 
-                        # check the active python and pip are in PYBIN
+                    which_pip = docker.call(['which', 'pip'], env=env, capture_output=True).strip()
-                        if [ "$(which pip)" != "$PYBIN/pip" ]; then
+                    if PurePath(which_pip) != python_bin / 'pip':
-                        echo "cibuildwheel: python available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert python above it."
+                        print("cibuildwheel: pip available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it.", file=sys.stderr)
-                        exit 1
+                        exit(1)
-                        fi
-                        if [ "$(which python)" != "$PYBIN/python" ]; then
-                        echo "cibuildwheel: pip available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it."
-                        exit 1
-                        fi
 
-                        if [ ! -z {before_build} ]; then
+                    if options.before_build:
-                            sh -c {before_build}
+                        before_build_prepared = prepare_command(options.before_build, project='/project', package=container_package_dir)
-                        fi
+                        docker.call(['sh', '-c', before_build_prepared], env=env)
 
-                        # Build the wheel
+                    temp_dir = PurePath('/tmp/cibuildwheel')
-                        rm -rf /tmp/built_wheel
+                    built_wheel_dir = temp_dir / 'built_wheel'
-                        mkdir /tmp/built_wheel
+                    docker.call(['rm', '-rf', built_wheel_dir])
-                        pip wheel {package_dir} -w /tmp/built_wheel --no-deps {build_verbosity_flag}
+                    docker.call(['mkdir', '-p', built_wheel_dir])
-                        built_wheel=(/tmp/built_wheel/*.whl)
 
-                        # repair the wheel
+                    docker.call([
-                        rm -rf /tmp/repaired_wheels
+                        'pip', 'wheel',
-                        mkdir /tmp/repaired_wheels
+                        container_package_dir,
-                        # NOTE: 'built_wheel' here is a bash array of glob matches; "$built_wheel" returns
+                        '-w', built_wheel_dir,
-                        # the first element
+                        '--no-deps',
-                        if [[ "$built_wheel" == *none-any.whl ]] || [ -z {repair_command} ]; then
+                        *get_build_verbosity_extra_flags(options.build_verbosity)
-                            # pure Python wheel or empty repair command
+                    ], env=env)
-                            mv "$built_wheel" /tmp/repaired_wheels
-                        else
-                            sh -c {repair_command} repair_command "$built_wheel"
-                        fi
-                        repaired_wheels=(/tmp/repaired_wheels/*.whl)
 
-                        if [ ! -z {test_command} ]; then
+                    built_wheel = docker.glob(built_wheel_dir, '*.whl')[0]
-                            # Set up a virtual environment to install and test from, to make sure
+
+                    repaired_wheel_dir = temp_dir / 'repaired_wheel'
+                    docker.call(['rm', '-rf', repaired_wheel_dir])
+                    docker.call(['mkdir', '-p', repaired_wheel_dir])
+
+                    if built_wheel.name.endswith('none-any.whl') or not options.repair_command:
+                        docker.call(['mv', built_wheel, repaired_wheel_dir])
+                    else:
+                        repair_command_prepared = prepare_command(options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir)
+                        docker.call(['sh', '-c', repair_command_prepared], env=env)
+
+                    repaired_wheels = docker.glob(repaired_wheel_dir, '*.whl')
+
+                    if options.test_command:
+                        # set up a virtual environment to install and test from, to make sure
                         # there are no dependencies that were pulled in at build time.
-                            pip install {dependency_install_flags} virtualenv
+                        docker.call(['pip', 'install', 'virtualenv', *dependency_constraint_flags], env=env)
-                            venv_dir=`mktemp -d`/venv
+                        venv_dir = PurePath(docker.call(['mktemp', '-d'], capture_output=True).strip()) / 'venv'
-                            python -m virtualenv --no-download "$venv_dir"
 
-                            # run the tests in a subshell to keep that `activate`
+                        docker.call(['python', '-m', 'virtualenv', '--no-download', venv_dir], env=env)
-                            # script from polluting the env
-                            (
-                                source "$venv_dir/bin/activate"
 
-                                echo "Running tests using `which python`"
+                        virtualenv_env = env.copy()
+                        virtualenv_env['PATH'] = f"{venv_dir / 'bin'}:{virtualenv_env['PATH']}"
 
-                                if [ ! -z {before_test} ]; then
+                        if options.before_test:
-                                    sh -c {before_test}
+                            before_test_prepared = prepare_command(options.before_test, project='/project', package=container_package_dir)
-                                fi
+                            docker.call(['sh', '-c', before_test_prepared], env=virtualenv_env)
 
                         # Install the wheel we just built
                         # Note: If auditwheel produced two wheels, it's because the earlier produced wheel
@@ -245,67 +202,30 @@ def build(options: BuildOptions) -> None:
                         # functionally the same, differing only in name, wheel metadata, and possibly include
                         # different external shared libraries. so it doesn't matter which one we run the tests on.
                         # Let's just pick the first one.
-                                pip install "${{repaired_wheels[0]}}"{test_extras}
+                        wheel_to_test = repaired_wheels[0]
+                        docker.call(['pip', 'install', str(wheel_to_test) + options.test_extras], env=virtualenv_env)
 
                         # Install any requirements to run the tests
-                                if [ ! -z "{test_requires}" ]; then
+                        if options.test_requires:
-                                    pip install {test_requires}
+                            docker.call(['pip', 'install', *options.test_requires], env=virtualenv_env)
-                                fi
 
                         # Run the tests from a different directory
-                                pushd $HOME
+                        test_command_prepared = prepare_command(options.test_command, project='/project', package=container_package_dir)
-                                sh -c {test_command}
+                        docker.call(['sh', '-c', test_command_prepared], cwd='/root', env=virtualenv_env)
-                                popd
-                            )
-                            # exit if tests failed (needed for older bash versions)
-                            if [ $? -ne 0 ]; then
-                              exit 1;
-                            fi
 
-                            # clean up
+                        # clean up test environment
-                            rm -rf "$venv_dir"
+                        docker.call(['rm', '-rf', venv_dir])
-                        fi
 
-                        # we're all done here; move it to output
+                    # move repaired wheels to output
-                        mv "${{repaired_wheels[@]}}" /output
+                    docker.call(['mkdir', '-p', container_output_dir])
-                        for repaired_wheel in "${{repaired_wheels[@]}}"; do
+                    docker.call(['mv', *repaired_wheels, container_output_dir])
-                            chown {uid}:{gid} "/output/$(basename "$repaired_wheel")"
-                        done
-                    '''.format(
-                        config_python_bin=config.path + '/bin',
-                        package_dir=container_package_dir,
-                        test_requires=' '.join(options.test_requires),
-                        test_extras=options.test_extras,
-                        test_command=shlex.quote(
-                            prepare_command(options.test_command, project='/project', package=container_package_dir) if options.test_command else ''
-                        ),
-                        before_build=shlex.quote(
-                            prepare_command(options.before_build, project='/project', package=container_package_dir) if options.before_build else ''
-                        ),
-                        build_verbosity_flag=' '.join(get_build_verbosity_extra_flags(options.build_verbosity)),
-                        repair_command=shlex.quote(
-                            prepare_command(options.repair_command, wheel='"$1"', dest_dir='/tmp/repaired_wheels') if options.repair_command else ''
-                        ),
-                        environment_exports='\n'.join(options.environment.as_shell_commands()),
-                        uid=os.getuid(),
-                        gid=os.getgid(),
-                        before_test=shlex.quote(
-                            prepare_command(options.before_test, project='/project', package=container_package_dir) if options.before_test else ''
-                        ),
-                        dependency_install_flags='-c /constraints.txt' if options.dependency_constraints else '',
-                    )
-                )
 
                 # copy the output back into the host
-            call(['docker', 'cp',
+                docker.copy_out(container_output_dir, options.output_dir)
-                  container_name + ':/output/.',
-                  str(options.output_dir.resolve())])
         except subprocess.CalledProcessError as error:
+            print(f'Command {error.cmd} failed with code {error.returncode}. {error.stdout}')
             troubleshoot(options.package_dir, error)
             exit(1)
-        finally:
-            # Still gets executed, even when 'exit(1)' gets called
-            call(['docker', 'rm', '--force', '-v', container_name])
 
 
 def troubleshoot(package_dir: Path, error: Exception) -> None:

cibuildwheel/macos.py

@@ -4,27 +4,22 @@ import shutil
 import subprocess
 import sys
 import tempfile
+from os import PathLike
 from pathlib import Path
-
+from typing import Dict, List, NamedTuple, Optional, Sequence, Union
-from typing import Dict, List, Optional, NamedTuple, Union
 
 from .environment import ParsedEnvironment
-from .util import (
+from .util import (BuildOptions, BuildSelector, download,
-    BuildOptions,
+                   get_build_verbosity_extra_flags, get_pip_script,
-    BuildSelector,
+                   prepare_command)
-    download,
-    get_build_verbosity_extra_flags,
-    get_pip_script,
-    prepare_command,
-)
 
 
-def call(args: Union[str, List[str]], env: Optional[Dict[str, str]] = None, cwd: Optional[str] = None, shell: bool = False) -> int:
+def call(args: Union[str, Sequence[Union[str, PathLike]]], env: Optional[Dict[str, str]] = None, cwd: Optional[str] = None, shell: bool = False) -> int:
     # print the command executing for the logs
     if shell:
         print(f'+ {args}')
     else:
-        print('+ ' + ' '.join(shlex.quote(a) for a in args))
+        print('+ ' + ' '.join(shlex.quote(str(a)) for a in args))
 
     return subprocess.check_call(args, env=env, cwd=cwd, shell=shell)
 
@@ -41,8 +36,8 @@ def get_python_configurations(build_selector: BuildSelector) -> List[PythonConfi
         PythonConfiguration(version='2.7', identifier='cp27-macosx_x86_64', url='https://www.python.org/ftp/python/2.7.18/python-2.7.18-macosx10.9.pkg'),
         PythonConfiguration(version='3.5', identifier='cp35-macosx_x86_64', url='https://www.python.org/ftp/python/3.5.4/python-3.5.4-macosx10.6.pkg'),
         PythonConfiguration(version='3.6', identifier='cp36-macosx_x86_64', url='https://www.python.org/ftp/python/3.6.8/python-3.6.8-macosx10.9.pkg'),
-        PythonConfiguration(version='3.7', identifier='cp37-macosx_x86_64', url='https://www.python.org/ftp/python/3.7.7/python-3.7.7-macosx10.9.pkg'),
+        PythonConfiguration(version='3.7', identifier='cp37-macosx_x86_64', url='https://www.python.org/ftp/python/3.7.8/python-3.7.8-macosx10.9.pkg'),
-        PythonConfiguration(version='3.8', identifier='cp38-macosx_x86_64', url='https://www.python.org/ftp/python/3.8.3/python-3.8.3-macosx10.9.pkg'),
+        PythonConfiguration(version='3.8', identifier='cp38-macosx_x86_64', url='https://www.python.org/ftp/python/3.8.4/python-3.8.4-macosx10.9.pkg'),
         # PyPy
         PythonConfiguration(version='2.7', identifier='pp27-macosx_x86_64', url='https://downloads.python.org/pypy/pypy2.7-v7.3.1-osx64.tar.bz2'),
         PythonConfiguration(version='3.6', identifier='pp36-macosx_x86_64', url='https://downloads.python.org/pypy/pypy3.6-v7.3.1-osx64.tar.bz2'),
@@ -103,7 +98,7 @@ def install_pypy(version: str, url: str) -> Path:
     if not installation_path.exists():
         downloaded_tar_bz2 = Path("/tmp") / pypy_tar_bz2
         download(url, downloaded_tar_bz2)
-        call(['tar', '-C', '/tmp', '-xf', str(downloaded_tar_bz2)])
+        call(['tar', '-C', '/tmp', '-xf', downloaded_tar_bz2])
 
     installation_bin_path = installation_path / 'bin'
     python_executable = 'pypy3' if version[0] == '3' else 'pypy'
@@ -113,7 +108,9 @@ def install_pypy(version: str, url: str) -> Path:
     return installation_bin_path
 
 
-def setup_python(python_configuration: PythonConfiguration, dependency_constraint_flags: List[str], environment: ParsedEnvironment) -> Dict[str, str]:
+def setup_python(python_configuration: PythonConfiguration,
+                 dependency_constraint_flags: Sequence[Union[str, PathLike]],
+                 environment: ParsedEnvironment) -> Dict[str, str]:
     if python_configuration.identifier.startswith('cp'):
         installation_bin_path = install_cpython(python_configuration.version, python_configuration.url)
     elif python_configuration.identifier.startswith('pp'):
@@ -146,7 +143,7 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
         exit(1)
 
     # install pip & wheel
-    call(['python', str(get_pip_script)] + dependency_constraint_flags, env=env, cwd="/tmp")
+    call(['python', get_pip_script, *dependency_constraint_flags], env=env, cwd="/tmp")
     assert (installation_bin_path / 'pip').exists()
     call(['which', 'pip'], env=env)
     call(['pip', '--version'], env=env)
@@ -154,7 +151,7 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
     if which_pip != '/tmp/cibw_bin/pip':
         print("cibuildwheel: pip available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert pip above it.", file=sys.stderr)
         exit(1)
-    call(['pip', 'install', '--upgrade', 'setuptools', 'wheel', 'delocate'] + dependency_constraint_flags, env=env)
+    call(['pip', 'install', '--upgrade', 'setuptools', 'wheel', 'delocate', *dependency_constraint_flags], env=env)
 
     # Set MACOSX_DEPLOYMENT_TARGET to 10.9, if the user didn't set it.
     # CPython 3.5 defaults to 10.6, and pypy defaults to 10.7, causing
@@ -184,10 +181,10 @@ def build(options: BuildOptions) -> None:
     python_configurations = get_python_configurations(options.build_selector)
 
     for config in python_configurations:
-        dependency_constraint_flags = []
+        dependency_constraint_flags: Sequence[Union[str, PathLike]] = []
         if options.dependency_constraints:
             dependency_constraint_flags = [
-                '-c', str(options.dependency_constraints.get_for_python_version(config.version))
+                '-c', options.dependency_constraints.get_for_python_version(config.version)
             ]
 
         env = setup_python(config, dependency_constraint_flags, options.environment)
@@ -201,9 +198,17 @@ def build(options: BuildOptions) -> None:
         if built_wheel_dir.exists():
             shutil.rmtree(built_wheel_dir)
         built_wheel_dir.mkdir(parents=True)
+
         # Path.resolve() is needed. Without it pip wheel may try to fetch package from pypi.org
         # see https://github.com/joerick/cibuildwheel/pull/369
-        call(['pip', 'wheel', str(options.package_dir.resolve()), '-w', str(built_wheel_dir), '--no-deps'] + get_build_verbosity_extra_flags(options.build_verbosity), env=env)
+        call([
+            'pip', 'wheel',
+            options.package_dir.resolve(),
+            '-w', built_wheel_dir,
+            '--no-deps',
+            *get_build_verbosity_extra_flags(options.build_verbosity)
+        ], env=env)
+
         built_wheel = next(built_wheel_dir.glob('*.whl'))
 
         # repair the wheel
@@ -212,7 +217,7 @@ def build(options: BuildOptions) -> None:
         repaired_wheel_dir.mkdir(parents=True)
         if built_wheel.name.endswith('none-any.whl') or not options.repair_command:
             # pure Python wheel or empty repair command
-            built_wheel.rename(repaired_wheel_dir / built_wheel.name)
+            shutil.move(str(built_wheel), repaired_wheel_dir)
         else:
             repair_command_prepared = prepare_command(options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir)
             call(repair_command_prepared, env=env, shell=True)
@@ -221,12 +226,12 @@ def build(options: BuildOptions) -> None:
         if options.test_command:
             # set up a virtual environment to install and test from, to make sure
             # there are no dependencies that were pulled in at build time.
-            call(['pip', 'install', 'virtualenv'] + dependency_constraint_flags, env=env)
+            call(['pip', 'install', 'virtualenv', *dependency_constraint_flags], env=env)
             venv_dir = Path(tempfile.mkdtemp())
 
             # Use --no-download to ensure determinism by using seed libraries
             # built into virtualenv
-            call(['python', '-m', 'virtualenv', '--no-download', str(venv_dir)], env=env)
+            call(['python', '-m', 'virtualenv', '--no-download', venv_dir], env=env)
 
             virtualenv_env = env.copy()
             virtualenv_env['PATH'] = os.pathsep.join([
@@ -262,4 +267,4 @@ def build(options: BuildOptions) -> None:
             shutil.rmtree(venv_dir)
 
         # we're all done here; move it to output (overwrite existing)
-        repaired_wheel.replace(options.output_dir / repaired_wheel.name)
+        shutil.move(str(repaired_wheel), options.output_dir)

cibuildwheel/windows.py

@@ -3,30 +3,32 @@ import shutil
 import subprocess
 import sys
 import tempfile
+from os import PathLike
 from pathlib import Path
+from typing import Dict, List, NamedTuple, Optional, Sequence, Union
 from zipfile import ZipFile
 import toml
 
-from typing import Dict, List, Optional, NamedTuple
-
 from .environment import ParsedEnvironment
-from .util import (
+from .util import (BuildOptions, BuildSelector, download,
-    BuildOptions,
+                   get_build_verbosity_extra_flags, get_pip_script,
-    BuildSelector,
+                   prepare_command)
-    download,
-    get_build_verbosity_extra_flags,
-    get_pip_script,
-    prepare_command,
-)
-
 
 IS_RUNNING_ON_AZURE = Path('C:\\hostedtoolcache').exists()
 IS_RUNNING_ON_TRAVIS = os.environ.get('TRAVIS_OS_NAME') == 'windows'
 
 
-def shell(args: List[str], env: Optional[Dict[str, str]] = None, cwd: Optional[str] = None) -> int:
+def call(args: Sequence[Union[str, PathLike]], env: Optional[Dict[str, str]] = None,
-    print('+ ' + ' '.join(args))
+         cwd: Optional[str] = None) -> None:
-    return subprocess.check_call(' '.join(args), env=env, cwd=cwd, shell=True)
+    print('+ ' + ' '.join(str(a) for a in args))
+    # we use shell=True here, even though we don't need a shell due to a bug
+    # https://bugs.python.org/issue8557
+    subprocess.check_call([str(a) for a in args], env=env, cwd=cwd, shell=True)
+
+
+def shell(command: str, env: Optional[Dict[str, str]] = None, cwd: Optional[str] = None) -> None:
+    print(f'+ {command}')
+    subprocess.check_call(command, env=env, cwd=cwd, shell=True)
 
 
 def get_nuget_args(version: str, arch: str) -> List[str]:
@@ -52,10 +54,10 @@ def get_python_configurations(build_selector: BuildSelector) -> List[PythonConfi
         PythonConfiguration(version='3.5.4', arch='64', identifier='cp35-win_amd64', url=None),
         PythonConfiguration(version='3.6.8', arch='32', identifier='cp36-win32', url=None),
         PythonConfiguration(version='3.6.8', arch='64', identifier='cp36-win_amd64', url=None),
-        PythonConfiguration(version='3.7.7', arch='32', identifier='cp37-win32', url=None),
+        PythonConfiguration(version='3.7.8', arch='32', identifier='cp37-win32', url=None),
-        PythonConfiguration(version='3.7.7', arch='64', identifier='cp37-win_amd64', url=None),
+        PythonConfiguration(version='3.7.8', arch='64', identifier='cp37-win_amd64', url=None),
-        PythonConfiguration(version='3.8.3', arch='32', identifier='cp38-win32', url=None),
+        PythonConfiguration(version='3.8.4', arch='32', identifier='cp38-win32', url=None),
-        PythonConfiguration(version='3.8.3', arch='64', identifier='cp38-win_amd64', url=None),
+        PythonConfiguration(version='3.8.4', arch='64', identifier='cp38-win_amd64', url=None),
         # PyPy
         PythonConfiguration(version='2.7', arch='32', identifier='pp27-win32', url='https://downloads.python.org/pypy/pypy2.7-v7.3.1-win32.zip'),
         PythonConfiguration(version='3.6', arch='32', identifier='pp36-win32', url='https://downloads.python.org/pypy/pypy3.6-v7.3.1-win32.zip'),
@@ -80,7 +82,7 @@ def extract_zip(zip_src: Path, dest: Path) -> None:
 def install_cpython(version: str, arch: str, nuget: Path) -> Path:
     nuget_args = get_nuget_args(version, arch)
     installation_path = Path(nuget_args[-1]) / (nuget_args[0] + '.' + version) / 'tools'
-    shell([str(nuget), 'install'] + nuget_args)
+    call([nuget, 'install', *nuget_args])
     return installation_path
 
 
@@ -101,7 +103,7 @@ def install_pypy(version: str, arch: str, url: str) -> Path:
     return installation_path
 
 
-def setup_python(python_configuration: PythonConfiguration, dependency_constraint_flags: List[str], environment: ParsedEnvironment) -> Dict[str, str]:
+def setup_python(python_configuration: PythonConfiguration, dependency_constraint_flags: Sequence[Union[str, PathLike]], environment: ParsedEnvironment) -> Dict[str, str]:
     nuget = Path('C:\\cibw\\nuget.exe')
     if not nuget.exists():
         download('https://dist.nuget.org/win-x86-commandline/latest/nuget.exe', nuget)
@@ -129,9 +131,9 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
     env = environment.as_dictionary(prev_environment=env)
 
     # for the logs - check we're running the right version of python
-    shell(['where', 'python'], env=env)
+    call(['where', 'python'], env=env)
-    shell(['python', '--version'], env=env)
+    call(['python', '--version'], env=env)
-    shell(['python', '-c', '"import struct; print(struct.calcsize(\'P\') * 8)"'], env=env)
+    call(['python', '-c', '"import struct; print(struct.calcsize(\'P\') * 8)"'], env=env)
     where_python = subprocess.check_output(['where', 'python'], env=env, universal_newlines=True).splitlines()[0].strip()
     if where_python != str(installation_path / 'python.exe'):
         print("cibuildwheel: python available on PATH doesn't match our installed instance. If you have modified PATH, ensure that you don't overwrite cibuildwheel's entry or insert python above it.", file=sys.stderr)
@@ -139,7 +141,7 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
 
     # make sure pip is installed
     if not (installation_path / 'Scripts' / 'pip.exe').exists():
-        shell(['python', str(get_pip_script)] + dependency_constraint_flags, env=env, cwd="C:\\cibw")
+        call(['python', get_pip_script, *dependency_constraint_flags], env=env, cwd="C:\\cibw")
     assert (installation_path / 'Scripts' / 'pip.exe').exists()
     where_pip = subprocess.check_output(['where', 'pip'], env=env, universal_newlines=True).splitlines()[0].strip()
     if where_pip.strip() != str(installation_path / 'Scripts' / 'pip.exe'):
@@ -147,9 +149,9 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
         exit(1)
 
     # prepare the Python environment
-    shell(['python', '-m', 'pip', 'install', '--upgrade', 'pip'] + dependency_constraint_flags, env=env)
+    call(['python', '-m', 'pip', 'install', '--upgrade', 'pip', *dependency_constraint_flags], env=env)
-    shell(['pip', '--version'], env=env)
+    call(['pip', '--version'], env=env)
-    shell(['pip', 'install', '--upgrade', 'setuptools', 'wheel'] + dependency_constraint_flags, env=env)
+    call(['pip', 'install', '--upgrade', 'setuptools', 'wheel', *dependency_constraint_flags], env=env)
 
     return env
 
@@ -191,14 +193,14 @@ def build(options: BuildOptions) -> None:
     if options.before_all:
         env = options.environment.as_dictionary(prev_environment=os.environ)
         before_all_prepared = prepare_command(options.before_all, project='.', package=options.package_dir)
-        shell([before_all_prepared], env=env)
+        shell(before_all_prepared, env=env)
 
     python_configurations = get_python_configurations(options.build_selector)
     for config in python_configurations:
-        dependency_constraint_flags = []
+        dependency_constraint_flags: Sequence[Union[str, PathLike]] = []
         if options.dependency_constraints:
             dependency_constraint_flags = [
-                '-c', str(options.dependency_constraints.get_for_python_version(config.version))
+                '-c', options.dependency_constraints.get_for_python_version(config.version)
             ]
 
         # install Python
@@ -207,7 +209,7 @@ def build(options: BuildOptions) -> None:
         # run the before_build command
         if options.before_build:
             before_build_prepared = prepare_command(options.before_build, project='.', package=options.package_dir)
-            shell([before_build_prepared], env=env)
+            shell(before_build_prepared, env=env)
 
         # activate the PEP 518 patch if on Windows Python 3.5
         # (will only have an effect if PEP 517 builds are used):
@@ -220,7 +222,14 @@ def build(options: BuildOptions) -> None:
         built_wheel_dir.mkdir(parents=True)
         # Path.resolve() is needed. Without it pip wheel may try to fetch package from pypi.org
         # see https://github.com/joerick/cibuildwheel/pull/369
-        shell(['pip', 'wheel', str(options.package_dir.resolve()), '-w', str(built_wheel_dir), '--no-deps'] + get_build_verbosity_extra_flags(options.build_verbosity), env=env)
+        call([
+            'pip', 'wheel',
+            options.package_dir.resolve(),
+            '-w', built_wheel_dir,
+            '--no-deps',
+            *get_build_verbosity_extra_flags(options.build_verbosity)
+        ], env=env)
+
         built_wheel = next(built_wheel_dir.glob('*.whl'))
 
         # repair the wheel
@@ -229,21 +238,21 @@ def build(options: BuildOptions) -> None:
         repaired_wheel_dir.mkdir(parents=True)
         if built_wheel.name.endswith('none-any.whl') or not options.repair_command:
             # pure Python wheel or empty repair command
-            built_wheel.rename(repaired_wheel_dir / built_wheel.name)
+            shutil.move(str(built_wheel), repaired_wheel_dir)
         else:
             repair_command_prepared = prepare_command(options.repair_command, wheel=built_wheel, dest_dir=repaired_wheel_dir)
-            shell([repair_command_prepared], env=env)
+            shell(repair_command_prepared, env=env)
         repaired_wheel = next(repaired_wheel_dir.glob('*.whl'))
 
         if options.test_command:
             # set up a virtual environment to install and test from, to make sure
             # there are no dependencies that were pulled in at build time.
-            shell(['pip', 'install', 'virtualenv'] + dependency_constraint_flags, env=env)
+            call(['pip', 'install', 'virtualenv', *dependency_constraint_flags], env=env)
             venv_dir = Path(tempfile.mkdtemp())
 
             # Use --no-download to ensure determinism by using seed libraries
             # built into virtualenv
-            shell(['python', '-m', 'virtualenv', '--no-download', str(venv_dir)], env=env)
+            call(['python', '-m', 'virtualenv', '--no-download', venv_dir], env=env)
 
             virtualenv_env = env.copy()
             virtualenv_env['PATH'] = os.pathsep.join([
@@ -252,7 +261,7 @@ def build(options: BuildOptions) -> None:
             ])
 
             # check that we are using the Python from the virtual environment
-            shell(['which', 'python'], env=virtualenv_env)
+            call(['which', 'python'], env=virtualenv_env)
 
             if options.before_test:
                 before_test_prepared = prepare_command(
@@ -260,14 +269,14 @@ def build(options: BuildOptions) -> None:
                     project='.',
                     package=options.package_dir
                 )
-                shell([before_test_prepared], env=virtualenv_env)
+                shell(before_test_prepared, env=virtualenv_env)
 
             # install the wheel
-            shell(['pip', 'install', str(repaired_wheel) + options.test_extras], env=virtualenv_env)
+            call(['pip', 'install', str(repaired_wheel) + options.test_extras], env=virtualenv_env)
 
             # test the wheel
             if options.test_requires:
-                shell(['pip', 'install'] + options.test_requires, env=virtualenv_env)
+                call(['pip', 'install'] + 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
@@ -277,10 +286,10 @@ def build(options: BuildOptions) -> None:
                 project=Path('.').resolve(),
                 package=options.package_dir.resolve()
             )
-            shell([test_command_prepared], cwd='c:\\', env=virtualenv_env)
+            shell(test_command_prepared, cwd='c:\\', env=virtualenv_env)
 
             # clean up
             shutil.rmtree(venv_dir)
 
         # we're all done here; move it to output (remove if already exists)
-        repaired_wheel.replace(options.output_dir / repaired_wheel.name)
+        shutil.move(str(repaired_wheel), options.output_dir)

docs/deliver-to-pypi.md

@@ -33,4 +33,4 @@ Obviously, manual steps are for chumps, so we can automate this a little by usin
 
 If you don't need much control over the release of a package, you can set up cibuildwheel to deliver the wheels straight to PyPI. This doesn't require anycloud storage to work - you just need to bump the version and tag it.
 
-[`examples/travis-deploy.yml`](https://github.com/joerick/cibuildwheel/blob/master/examples/travis-deploy.yml) and [`examples/github-deploy.yml`](https://github.com/joerick/cibuildwheel/blob/master/examples/travis-deploy.yml) are example configurations that automatocially upload wheels to PyPI. Also check out [this example repo](https://github.com/joerick/cibuildwheel-autopypi-example) for more detailed instructions on how to set this up.
+[`examples/travis-ci-deploy.yml`](https://github.com/joerick/cibuildwheel/blob/master/examples/travis-ci-deploy.yml) and [`examples/github-deploy.yml`](https://github.com/joerick/cibuildwheel/blob/master/examples/github-deploy.yml) are example configurations that automatically upload wheels to PyPI. Also check out [this example repo](https://github.com/joerick/cibuildwheel-autopypi-example) for more detailed instructions on how to set this up.

examples/appveyor-minimal.yml

@@ -12,7 +12,7 @@ stack: python 3.7
 init:
 - cmd: set PATH=C:\Python37;C:\Python37\Scripts;%PATH%
 
-install: python -m pip install cibuildwheel==1.5.0
+install: python -m pip install cibuildwheel==1.5.5
 
 build_script: python -m cibuildwheel --output-dir wheelhouse
 

examples/azure-pipelines-minimal.yml

@@ -5,7 +5,7 @@ jobs:
     - task: UsePythonVersion@0
     - bash: |
         python3 -m pip install --upgrade pip
-        pip3 install cibuildwheel==1.5.0
+        pip3 install cibuildwheel==1.5.5
         cibuildwheel --output-dir wheelhouse .
     - task: PublishBuildArtifacts@1
       inputs: {pathtoPublish: 'wheelhouse'}
@@ -16,7 +16,7 @@ jobs:
     - task: UsePythonVersion@0
     - bash: |
         python3 -m pip install --upgrade pip
-        pip3 install cibuildwheel==1.5.0
+        pip3 install cibuildwheel==1.5.5
         cibuildwheel --output-dir wheelhouse .
     - task: PublishBuildArtifacts@1
       inputs: {pathtoPublish: 'wheelhouse'}
@@ -29,7 +29,7 @@ jobs:
       displayName: Install Visual C++ for Python 2.7
     - bash: |
         python -m pip install --upgrade pip
-        pip install cibuildwheel==1.5.0
+        pip install cibuildwheel==1.5.5
         cibuildwheel --output-dir wheelhouse .
     - task: PublishBuildArtifacts@1
       inputs: {pathtoPublish: 'wheelhouse'}

examples/circleci-minimal.yml

@@ -11,7 +11,7 @@ jobs:
       - run:
           name: Build the Linux wheels.
           command: |
-            pip3 install --user cibuildwheel==1.5.0
+            pip3 install --user cibuildwheel==1.5.5
             cibuildwheel --output-dir wheelhouse
       - store_artifacts:
           path: wheelhouse/
@@ -25,7 +25,7 @@ jobs:
       - run:
           name: Build the OS X wheels.
           command: |
-            pip3 install --user cibuildwheel==1.5.0
+            pip3 install --user cibuildwheel==1.5.5
             cibuildwheel --output-dir wheelhouse
       - store_artifacts:
           path: wheelhouse/

examples/github-deploy.yml

@@ -28,7 +28,7 @@ jobs:
 
       - name: Install cibuildwheel
         run: |
-          python -m pip install cibuildwheel==1.5.0
+          python -m pip install cibuildwheel==1.5.5
 
       - name: Install Visual C++ for Python 2.7
         if: runner.os == 'Windows'

examples/github-minimal.yml

@@ -20,7 +20,7 @@ jobs:
 
       - name: Install cibuildwheel
         run: |
-          python -m pip install cibuildwheel==1.5.0
+          python -m pip install cibuildwheel==1.5.5
 
       - name: Install Visual C++ for Python 2.7
         if: runner.os == 'Windows'

examples/travis-ci-deploy.yml

@@ -25,7 +25,7 @@ env:
     # Note: TWINE_PASSWORD is set to a PyPI API token in Travis settings
 
 install:
-  - python3 -m pip install cibuildwheel==1.5.0
+  - python3 -m pip install cibuildwheel==1.5.5
 
 script:
   # build the wheels, put them into './wheelhouse'

examples/travis-ci-minimal.yml

@@ -26,7 +26,7 @@ jobs:
         - ln -s /c/Python38/python.exe /c/Python38/python3.exe
 
 install:
-  - python3 -m pip install cibuildwheel==1.5.0
+  - python3 -m pip install cibuildwheel==1.5.5
 
 script:
   # build the wheels, put them into './wheelhouse'

examples/travis-ci-test-and-deploy.yml

@@ -55,7 +55,7 @@ jobs:
     - stage: deploy
       name: Build and deploy Linux wheels
       services: docker
-      install: python3 -m pip install cibuildwheel==1.5.0
+      install: python3 -m pip install cibuildwheel==1.5.5
       script: python3 -m cibuildwheel --output-dir wheelhouse
       after_success: |
         python3 -m pip install twine
@@ -65,7 +65,7 @@ jobs:
       name: Build and deploy macOS wheels
       os: osx
       language: shell
-      install: python3 -m pip install cibuildwheel==1.5.0
+      install: python3 -m pip install cibuildwheel==1.5.5
       script: python3 -m cibuildwheel --output-dir wheelhouse
       after_success: |
         python3 -m pip install twine
@@ -75,7 +75,7 @@ jobs:
       name: Build and deploy Windows wheels
       os: windows
       language: shell
-      install: python3 -m pip install cibuildwheel==1.5.0
+      install: python3 -m pip install cibuildwheel==1.5.5
       script: python3 -m cibuildwheel --output-dir wheelhouse
       after_success: |
         python3 -m pip install twine

requirements-dev.txt

@@ -6,3 +6,5 @@ pymdown-extensions
 pip-tools
 requests
 click
+mypy
+typing-extensions

setup.cfg

@@ -1,5 +1,5 @@
 [flake8]
-ignore = E501,W503,E741
+ignore = E501,W503,E741,E226
 application-import-names = cibuildwheel
 exclude =
   cibuildwheel/resources/,

setup.py

@@ -11,7 +11,7 @@ long_description = (this_directory / 'README.md').read_text(encoding='utf-8')
 
 setup(
     name='cibuildwheel',
-    version='1.5.0',
+    version='1.5.5',
     install_requires=['bashlex!=0.13', 'toml'],
     description="Build Python wheels on CI with minimal configuration.",
     long_description=long_description,

test/test_before_all.py

@@ -1,4 +1,5 @@
-import os
+import pytest
+import subprocess
 import textwrap
 
 from . import utils
@@ -21,7 +22,7 @@ def test(tmp_path):
     project_dir = tmp_path / 'project'
     project_with_before_build_asserts.generate(project_dir)
 
-    with open(os.path.join(project_dir, "text_info.txt"), mode='w') as ff:
+    with (project_dir / 'text_info.txt').open(mode='w') as ff:
         print("dummy text", file=ff)
 
     # build the wheels
@@ -33,6 +34,30 @@ def test(tmp_path):
     })
 
     # also check that we got the right wheels
-    os.remove(os.path.join(project_dir, "text_info.txt"))
+    (project_dir / 'text_info.txt').unlink()
+    expected_wheels = utils.expected_wheels('spam', '0.1.0')
+    assert set(actual_wheels) == set(expected_wheels)
+
+
+def test_failing_command(tmp_path):
+    project_dir = tmp_path / 'project'
+    test_projects.new_c_project().generate(project_dir)
+
+    with pytest.raises(subprocess.CalledProcessError):
+        utils.cibuildwheel_run(project_dir, add_env={
+            'CIBW_BEFORE_ALL': 'false',
+            'CIBW_BEFORE_ALL_WINDOWS': 'exit /b 1',
+        })
+
+
+def test_cwd(tmp_path):
+    project_dir = tmp_path / 'project'
+    test_projects.new_c_project().generate(project_dir)
+
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
+        'CIBW_BEFORE_ALL': f'''python -c "import os; assert os.getcwd() == {str(project_dir)!r}"''',
+        'CIBW_BEFORE_ALL_LINUX': '''python -c "import os; assert os.getcwd() == '/project'"''',
+    })
+
     expected_wheels = utils.expected_wheels('spam', '0.1.0')
     assert set(actual_wheels) == set(expected_wheels)

test/test_before_build.py

@@ -1,3 +1,5 @@
+import pytest
+import subprocess
 import textwrap
 
 from . import utils
@@ -32,14 +34,41 @@ def test(tmp_path):
     project_dir = tmp_path / 'project'
     project_with_before_build_asserts.generate(project_dir)
 
+    before_build = ('''python -c "import sys; open('{output_dir}pythonversion.txt', 'w').write(sys.version)" && '''
+                    '''python -c "import sys; open('{output_dir}pythonexecutable.txt', 'w').write(sys.executable)"''')
+
     # build the wheels
     actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
         # write python version information to a temporary file, this is
         # checked in setup.py
-        'CIBW_BEFORE_BUILD': '''python -c "import sys; open('/tmp/pythonversion.txt', 'w').write(sys.version)" && python -c "import sys; open('/tmp/pythonexecutable.txt', 'w').write(sys.executable)"''',
+        'CIBW_BEFORE_BUILD': before_build.format(output_dir='/tmp/'),
-        'CIBW_BEFORE_BUILD_WINDOWS': '''python -c "import sys; open('c:\\pythonversion.txt', 'w').write(sys.version)" && python -c "import sys; open('c:\\pythonexecutable.txt', 'w').write(sys.executable)"''',
+        'CIBW_BEFORE_BUILD_WINDOWS': before_build.format(output_dir=r'c:\\'),
     })
 
     # also check that we got the right wheels
     expected_wheels = utils.expected_wheels('spam', '0.1.0')
     assert set(actual_wheels) == set(expected_wheels)
+
+
+def test_failing_command(tmp_path):
+    project_dir = tmp_path / 'project'
+    test_projects.new_c_project().generate(project_dir)
+
+    with pytest.raises(subprocess.CalledProcessError):
+        utils.cibuildwheel_run(project_dir, add_env={
+            'CIBW_BEFORE_BUILD': 'false',
+            'CIBW_BEFORE_BUILD_WINDOWS': 'exit /b 1',
+        })
+
+
+def test_cwd(tmp_path):
+    project_dir = tmp_path / 'project'
+    test_projects.new_c_project().generate(project_dir)
+
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
+        'CIBW_BEFORE_BUILD': f'''python -c "import os; assert os.getcwd() == {str(project_dir)!r}"''',
+        'CIBW_BEFORE_BUILD_LINUX': '''python -c "import os; assert os.getcwd() == '/project'"''',
+    })
+
+    expected_wheels = utils.expected_wheels('spam', '0.1.0')
+    assert set(actual_wheels) == set(expected_wheels)

test/test_environment.py

@@ -13,12 +13,15 @@ project_with_environment_asserts = test_projects.new_c_project(
         # explode if environment isn't correct, as set in CIBW_ENVIRONMENT
         CIBW_TEST_VAR = os.environ.get("CIBW_TEST_VAR")
         CIBW_TEST_VAR_2 = os.environ.get("CIBW_TEST_VAR_2")
+        CIBW_TEST_VAR_3 = os.environ.get("CIBW_TEST_VAR_3")
         PATH = os.environ.get("PATH")
 
         if CIBW_TEST_VAR != "a b c":
             raise Exception('CIBW_TEST_VAR should equal "a b c". It was "%s"' % CIBW_TEST_VAR)
         if CIBW_TEST_VAR_2 != "1":
             raise Exception('CIBW_TEST_VAR_2 should equal "1". It was "%s"' % CIBW_TEST_VAR_2)
+        if CIBW_TEST_VAR_3 != "test string 3":
+            raise Exception('CIBW_TEST_VAR_3 should equal "test string 3". It was "%s"' % CIBW_TEST_VAR_3)
         if "/opt/cibw_test_path" not in PATH:
             raise Exception('PATH should contain "/opt/cibw_test_path". It was "%s"' % PATH)
         if "$PATH" in PATH:
@@ -44,7 +47,7 @@ def test(tmp_path):
     assert set(actual_wheels) == set(expected_wheels)
 
 
-def test_overridden_path(tmp_path):
+def test_overridden_path(tmp_path, capfd):
     project_dir = tmp_path / 'project'
     output_dir = tmp_path / 'output'
 
@@ -54,8 +57,21 @@ def test_overridden_path(tmp_path):
 
     # mess up PATH, somehow
     with pytest.raises(subprocess.CalledProcessError):
+        if utils.platform == 'linux':
             utils.cibuildwheel_run(project_dir, output_dir=output_dir, add_env={
-            'CIBW_ENVIRONMENT': '''SOMETHING="$(mkdir new_path && touch new_path/python)" PATH="$(realpath new_path):$PATH"''',
+                'CIBW_BEFORE_ALL': 'mkdir new_path && touch new_path/python && chmod +x new_path/python',
-            'CIBW_ENVIRONMENT_WINDOWS': '''SOMETHING="$(mkdir new_path && type nul > new_path/python.exe)" PATH="$CD\\new_path;$PATH"''',
+                'CIBW_ENVIRONMENT': '''PATH="$(pwd)/new_path:$PATH"''',
             })
+        else:
+            new_path = tmp_path / 'another_bin'
+            new_path.mkdir()
+            (new_path / 'python').touch(mode=0o777)
+
+            utils.cibuildwheel_run(project_dir, output_dir=output_dir, add_env={
+                'NEW_PATH': str(new_path),
+                'CIBW_ENVIRONMENT': f'''PATH="$NEW_PATH{os.pathsep}$PATH"''',
+            })
+
     assert len(os.listdir(output_dir)) == 0
+    captured = capfd.readouterr()
+    assert "python available on PATH doesn't match our installed instance" in captured.err

test/test_pep518.py

@@ -6,7 +6,11 @@ basic_project = test_projects.new_c_project(
     setup_py_add=textwrap.dedent(
         """
         # Will fail if PEP 518 does work
+        import sys
         import requests
+        if sys.version_info < (3, 6, 0):
+            assert requests.__version__ == "2.22.0", "Requests found but wrong version ({0})".format(requests.__version__)
+        else:
             assert requests.__version__ == "2.23.0", "Requests found but wrong version ({0})".format(requests.__version__)
 
         # Just making sure environment is still set
@@ -24,7 +28,8 @@ basic_project.files[
 requires = [
     "setuptools >= 42",
     "wheel",
-    "requests==2.23.0"
+    "requests==2.22.0; python_version<'3.6'",
+    "requests==2.23.0; python_version>='3.6'"
 ]
 
 build-backend = "setuptools.build_meta"

test/test_projects/__main__.py

@@ -1,8 +1,9 @@
-from argparse import ArgumentParser
 import importlib
-import tempfile
-import sys
 import subprocess
+import sys
+import tempfile
+from argparse import ArgumentParser
+from pathlib import Path
 
 
 def main():
@@ -19,7 +20,7 @@ def main():
 
     project = getattr(importlib.import_module(module), name)
 
-    project_dir = tempfile.mkdtemp()
+    project_dir = Path(tempfile.mkdtemp())
     project.generate(project_dir)
 
     print('Project generated at', project_dir)

unit_test/conftest.py

@@ -0,0 +1,21 @@
+import pytest
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--run-docker", action="store_true", default=False, help="run docker tests"
+    )
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "docker: mark test requiring docker to run")
+
+
+def pytest_collection_modifyitems(config, items):
+    if config.getoption("--run-docker"):
+        # --run-docker given in cli: do not skip docker tests
+        return
+    skip_docker = pytest.mark.skip(reason="need --run-docker option to run")
+    for item in items:
+        if "docker" in item.keywords:
+            item.add_marker(skip_docker)

unit_test/docker_container_test.py

@@ -0,0 +1,162 @@
+import platform
+import random
+import shutil
+import subprocess
+import textwrap
+from pathlib import Path, PurePath
+
+import pytest
+
+from cibuildwheel.docker_container import DockerContainer
+from cibuildwheel.environment import EnvironmentAssignment
+
+# for these tests we use manylinux2014 images, because they're available on
+# multi architectures and include python3.8
+pm = platform.machine()
+if pm == "x86_64":
+    DEFAULT_IMAGE = 'quay.io/pypa/manylinux2014_x86_64:2020-05-17-2f8ac3b'
+elif pm == "aarch64":
+    DEFAULT_IMAGE = 'quay.io/pypa/manylinux2014_aarch64:2020-05-17-2f8ac3b'
+elif pm == "ppc64le":
+    DEFAULT_IMAGE = 'quay.io/pypa/manylinux2014_ppc64le:2020-05-17-2f8ac3b'
+elif pm == "s390x":
+    DEFAULT_IMAGE = 'quay.io/pypa/manylinux2014_s390x:2020-05-17-2f8ac3b'
+
+
+@pytest.mark.docker
+def test_simple():
+    with DockerContainer(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:
+        assert container.call(['printf', 'hello'], capture_output=True) == 'hello'
+
+
+@pytest.mark.docker
+def test_environment():
+    with DockerContainer(DEFAULT_IMAGE) as container:
+        assert container.call(['sh', '-c', 'echo $TEST_VAR'], env={'TEST_VAR': '1'}, capture_output=True) == '1\n'
+
+
+@pytest.mark.docker
+def test_cwd():
+    with DockerContainer(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:
+        docker_containers_listing = subprocess.run('docker container ls', shell=True, check=True, stdout=subprocess.PIPE, universal_newlines=True).stdout
+        assert container.name in docker_containers_listing
+        old_container_name = container.name
+
+    docker_containers_listing = subprocess.run('docker container ls', shell=True, check=True, stdout=subprocess.PIPE, universal_newlines=True).stdout
+    assert old_container_name not in docker_containers_listing
+
+
+@pytest.mark.docker
+def test_large_environment():
+    # max environment variable size is 128kB
+    long_env_var_length = 127*1024
+    large_environment = {
+        'a': '0'*long_env_var_length,
+        'b': '0'*long_env_var_length,
+        'c': '0'*long_env_var_length,
+        'd': '0'*long_env_var_length,
+    }
+
+    with DockerContainer(DEFAULT_IMAGE) as container:
+        # check the length of d
+        assert container.call(['sh', '-c', 'echo ${#d}'], env=large_environment, capture_output=True) == f'{long_env_var_length}\n'
+
+
+@pytest.mark.docker
+def test_binary_output():
+    with DockerContainer(DEFAULT_IMAGE) as container:
+        # note: the below embedded snippets are in python2
+
+        # check that we can pass though arbitrary binary data without erroring
+        container.call(['/usr/bin/python2', '-c', textwrap.dedent('''
+            import sys
+            sys.stdout.write(''.join(chr(n) for n in range(0, 256)))
+        ''')])
+
+        # check that we can capture arbitrary binary data
+        output = container.call(['/usr/bin/python2', '-c', textwrap.dedent('''
+            import sys
+            sys.stdout.write(''.join(chr(n % 256) for n in range(0, 512)))
+        ''')], capture_output=True)
+
+        data = bytes(output, encoding='utf8', errors='surrogateescape')
+
+        for i in range(0, 512):
+            assert data[i] == i % 256
+
+        # check that environment variables can carry binary data, except null characters
+        # (https://www.gnu.org/software/libc/manual/html_node/Environment-Variables.html)
+        binary_data = bytes(n for n in range(1, 256))
+        binary_data_string = str(binary_data, encoding='utf8', errors='surrogateescape')
+        output = container.call(
+            ['python2', '-c', 'import os, sys; sys.stdout.write(os.environ["TEST_VAR"])'],
+            env={'TEST_VAR': binary_data_string},
+            capture_output=True,
+        )
+        assert output == binary_data_string
+
+
+@pytest.mark.docker
+def test_file_operations(tmp_path: Path):
+    with DockerContainer(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'
+        original_test_file.write_bytes(test_binary_data)
+
+        dst_file = PurePath('/tmp/test.dat')
+
+        container.copy_into(original_test_file, dst_file)
+
+        output = container.call(['cat', dst_file], capture_output=True)
+        assert test_binary_data == bytes(output, encoding='utf8', errors='surrogateescape')
+
+
+@pytest.mark.docker
+def test_dir_operations(tmp_path: Path):
+    with DockerContainer(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)
+
+        # test copying a dir in
+        test_dir = tmp_path / 'test_dir'
+        test_dir.mkdir()
+        test_file = test_dir / 'test.dat'
+        shutil.copyfile(original_test_file, test_file)
+
+        dst_dir = PurePath('/tmp/test_dir')
+        dst_file = dst_dir / 'test.dat'
+        container.copy_into(test_dir, dst_dir)
+
+        output = container.call(['cat', dst_file], capture_output=True)
+        assert test_binary_data == bytes(output, encoding='utf8', errors='surrogateescape')
+
+        # test glob
+        assert container.glob(dst_dir, '*.dat') == [dst_file]
+
+        # test copy dir out
+        new_test_dir = tmp_path / 'test_dir_new'
+        container.copy_out(dst_dir, new_test_dir)
+
+        assert test_binary_data == (new_test_dir / 'test.dat').read_bytes()
+
+
+@pytest.mark.docker
+def test_environment_executor():
+    with DockerContainer(DEFAULT_IMAGE) as container:
+        assignment = EnvironmentAssignment("TEST=$(echo 42)")
+        assert assignment.evaluated_value({}, container.environment_executor) == "42"

unit_test/environment_test.py

@@ -94,3 +94,32 @@ def test_no_vars_pass_through():
     environment_dict = environment_recipe.as_dictionary(prev_environment={'CIBUILDWHEEL': 'awesome'})
 
     assert environment_dict == {'CIBUILDWHEEL': 'awesome'}
+
+
+def test_operators_inside_eval():
+    environment_recipe = parse_environment('SOMETHING="$(echo a; echo b; echo c)"')
+
+    # pass the existing process env so PATH is available
+    environment_dict = environment_recipe.as_dictionary(os.environ.copy())
+
+    assert environment_dict.get('SOMETHING') == 'a\nb\nc'
+
+
+def test_substitution_with_backslash():
+    environment_recipe = parse_environment('PATH2="somewhere_else;$PATH1"')
+
+    # pass the existing process env so PATH is available
+    environment_dict = environment_recipe.as_dictionary(prev_environment={
+        'PATH1': 'c:\\folder\\'
+    })
+
+    assert environment_dict.get('PATH2') == 'somewhere_else;c:\\folder\\'
+
+
+def test_awkwardly_quoted_variable():
+    environment_recipe = parse_environment('VAR2=something"like this""$VAR1"$VAR1$(echo "theres more")"$(echo "and more!")"')
+
+    # pass the existing process env so PATH is available
+    environment_dict = environment_recipe.as_dictionary({'VAR1': 'but wait'})
+
+    assert environment_dict.get('VAR2') == 'somethinglike thisbut waitbut waittheres moreand more!'