cmdline.py

# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt

"""Command-line support for coverage.py."""

from __future__ import annotations

import glob
import optparse     # pylint: disable=deprecated-module
import os
import os.path
import shlex
import sys
import textwrap
import traceback

from typing import cast, Any, List, NoReturn, Optional, Tuple

import coverage
from coverage import Coverage
from coverage import env
from coverage.collector import HAS_CTRACER
from coverage.config import CoverageConfig
from coverage.control import DEFAULT_DATAFILE
from coverage.data import combinable_files, debug_data_file
from coverage.debug import info_header, short_stack, write_formatted_info
from coverage.exceptions import _BaseCoverageException, _ExceptionDuringRun, NoSource
from coverage.execfile import PyRunner
from coverage.results import Numbers, should_fail_under
from coverage.version import __url__

# When adding to this file, alphabetization is important.  Look for
# "alphabetize" comments throughout.

class Opts:
    """A namespace class for individual options we'll build parsers from."""

    # Keep these entries alphabetized (roughly) by the option name as it
    # appears on the command line.

    append = optparse.make_option(
        "-a", "--append", action="store_true",
        help="Append coverage data to .coverage, otherwise it starts clean each time.",
    )
    branch = optparse.make_option(
        "", "--branch", action="store_true",
        help="Measure branch coverage in addition to statement coverage.",
    )
    CONCURRENCY_CHOICES = [
        "thread", "gevent", "greenlet", "eventlet", "multiprocessing",
    ]
    concurrency = optparse.make_option(
        '', '--concurrency', action='store', metavar="LIB",
        choices=CONCURRENCY_CHOICES,
        help=(
            "Properly measure code using a concurrency library. " +
            "Valid values are: {}."
        ).format(", ".join(CONCURRENCY_CHOICES)),
    )
    context = optparse.make_option(
        "", "--context", action="store", metavar="LABEL",
        help="The context label to record for this coverage run.",
    )
    contexts = optparse.make_option(
        "", "--contexts", action="store", metavar="REGEX1,REGEX2,...",
        help=(
            "Only display data from lines covered in the given contexts. " +
            "Accepts Python regexes, which must be quoted."
        ),
    )
    datafile = optparse.make_option(
        "", "--data-file", action="store", metavar="DATAFILE",
        help=(
            "Base name of the data files to operate on. " +
            "Defaults to '.coverage'. [env: COVERAGE_FILE]"
        ),
    )
    datafle_input = optparse.make_option(
        "", "--data-file", action="store", metavar="INFILE",
        help=(
            "Read coverage data for report generation from this file. " +
            "Defaults to '.coverage'. [env: COVERAGE_FILE]"
        ),
    )
    datafile_output = optparse.make_option(
        "", "--data-file", action="store", metavar="OUTFILE",
        help=(
            "Write the recorded coverage data to this file. " +
            "Defaults to '.coverage'. [env: COVERAGE_FILE]"
        ),
    )
    debug = optparse.make_option(
        "", "--debug", action="store", metavar="OPTS",
        help="Debug options, separated by commas. [env: COVERAGE_DEBUG]",
    )
    directory = optparse.make_option(
        "-d", "--directory", action="store", metavar="DIR",
        help="Write the output files to DIR.",
    )
    fail_under = optparse.make_option(
        "", "--fail-under", action="store", metavar="MIN", type="float",
        help="Exit with a status of 2 if the total coverage is less than MIN.",
    )
    format = optparse.make_option(
        "", "--format", action="store", metavar="FORMAT",
        help="Output format, either text (default), markdown, or total.",
    )
    help = optparse.make_option(
        "-h", "--help", action="store_true",
        help="Get help on this command.",
    )
    ignore_errors = optparse.make_option(
        "-i", "--ignore-errors", action="store_true",
        help="Ignore errors while reading source files.",
    )
    include = optparse.make_option(
        "", "--include", action="store", metavar="PAT1,PAT2,...",
        help=(
            "Include only files whose paths match one of these patterns. " +
            "Accepts shell-style wildcards, which must be quoted."
        ),
    )
    keep = optparse.make_option(
        "", "--keep", action="store_true",
        help="Keep original coverage files, otherwise they are deleted.",
    )
    pylib = optparse.make_option(
        "-L", "--pylib", action="store_true",
        help=(
            "Measure coverage even inside the Python installed library, " +
            "which isn't done by default."
        ),
    )
    show_missing = optparse.make_option(
        "-m", "--show-missing", action="store_true",
        help="Show line numbers of statements in each module that weren't executed.",
    )
    module = optparse.make_option(
        "-m", "--module", action="store_true",
        help=(
            "<pyfile> is an importable Python module, not a script path, " +
            "to be run as 'python -m' would run it."
        ),
    )
    omit = optparse.make_option(
        "", "--omit", action="store", metavar="PAT1,PAT2,...",
        help=(
            "Omit files whose paths match one of these patterns. " +
            "Accepts shell-style wildcards, which must be quoted."
        ),
    )
    output_xml = optparse.make_option(
        "-o", "", action="store", dest="outfile", metavar="OUTFILE",
        help="Write the XML report to this file. Defaults to 'coverage.xml'",
    )
    output_json = optparse.make_option(
        "-o", "", action="store", dest="outfile", metavar="OUTFILE",
        help="Write the JSON report to this file. Defaults to 'coverage.json'",
    )
    output_lcov = optparse.make_option(
        "-o", "", action="store", dest="outfile", metavar="OUTFILE",
        help="Write the LCOV report to this file. Defaults to 'coverage.lcov'",
    )
    json_pretty_print = optparse.make_option(
        "", "--pretty-print", action="store_true",
        help="Format the JSON for human readers.",
    )
    parallel_mode = optparse.make_option(
        "-p", "--parallel-mode", action="store_true",
        help=(
            "Append the machine name, process id and random number to the " +
            "data file name to simplify collecting data from " +
            "many processes."
        ),
    )
    precision = optparse.make_option(
        "", "--precision", action="store", metavar="N", type=int,
        help=(
            "Number of digits after the decimal point to display for " +
            "reported coverage percentages."
        ),
    )
    quiet = optparse.make_option(
        "-q", "--quiet", action="store_true",
        help="Don't print messages about what is happening.",
    )
    rcfile = optparse.make_option(
        "", "--rcfile", action="store",
        help=(
            "Specify configuration file. " +
            "By default '.coveragerc', 'setup.cfg', 'tox.ini', and " +
            "'pyproject.toml' are tried. [env: COVERAGE_RCFILE]"
        ),
    )
    show_contexts = optparse.make_option(
        "--show-contexts", action="store_true",
        help="Show contexts for covered lines.",
    )
    skip_covered = optparse.make_option(
        "--skip-covered", action="store_true",
        help="Skip files with 100% coverage.",
    )
    no_skip_covered = optparse.make_option(
        "--no-skip-covered", action="store_false", dest="skip_covered",
        help="Disable --skip-covered.",
    )
    skip_empty = optparse.make_option(
        "--skip-empty", action="store_true",
        help="Skip files with no code.",
    )
    sort = optparse.make_option(
        "--sort", action="store", metavar="COLUMN",
        help=(
            "Sort the report by the named column: name, stmts, miss, branch, brpart, or cover. " +
             "Default is name."
        ),
    )
    source = optparse.make_option(
        "", "--source", action="store", metavar="SRC1,SRC2,...",
        help="A list of directories or importable names of code to measure.",
    )
    timid = optparse.make_option(
        "", "--timid", action="store_true",
        help="Use the slower Python trace function core.",
    )
    title = optparse.make_option(
        "", "--title", action="store", metavar="TITLE",
        help="A text string to use as the title on the HTML.",
    )
    version = optparse.make_option(
        "", "--version", action="store_true",
        help="Display version information and exit.",
    )


class CoverageOptionParser(optparse.OptionParser):
    """Base OptionParser for coverage.py.

    Problems don't exit the program.
    Defaults are initialized for all options.

    """

    def __init__(self, *args: Any, **kwargs: Any) -> None:
        kwargs["add_help_option"] = False
        super().__init__(*args, **kwargs)
        self.set_defaults(
            # Keep these arguments alphabetized by their names.
            action=None,
            append=None,
            branch=None,
            concurrency=None,
            context=None,
            contexts=None,
            data_file=None,
            debug=None,
            directory=None,
            fail_under=None,
            format=None,
            help=None,
            ignore_errors=None,
            include=None,
            keep=None,
            module=None,
            omit=None,
            parallel_mode=None,
            precision=None,
            pylib=None,
            quiet=None,
            rcfile=True,
            show_contexts=None,
            show_missing=None,
            skip_covered=None,
            skip_empty=None,
            sort=None,
            source=None,
            timid=None,
            title=None,
            version=None,
        )

        self.disable_interspersed_args()

    class OptionParserError(Exception):
        """Used to stop the optparse error handler ending the process."""
        pass

    def parse_args_ok(self, args: List[str]) -> Tuple[bool, Optional[optparse.Values], List[str]]:
        """Call optparse.parse_args, but return a triple:

        (ok, options, args)

        """
        try:
            options, args = super().parse_args(args)
        except self.OptionParserError:
            return False, None, []
        return True, options, args

    def error(self, msg: str) -> NoReturn:
        """Override optparse.error so sys.exit doesn't get called."""
        show_help(msg)
        raise self.OptionParserError


class GlobalOptionParser(CoverageOptionParser):
    """Command-line parser for coverage.py global option arguments."""

    def __init__(self) -> None:
        super().__init__()

        self.add_options([
            Opts.help,
            Opts.version,
        ])


class CmdOptionParser(CoverageOptionParser):
    """Parse one of the new-style commands for coverage.py."""

    def __init__(
        self,
        action: str,
        options: List[optparse.Option],
        description: str,
        usage: Optional[str] = None,
    ):
        """Create an OptionParser for a coverage.py command.

        `action` is the slug to put into `options.action`.
        `options` is a list of Option's for the command.
        `description` is the description of the command, for the help text.
        `usage` is the usage string to display in help.

        """
        if usage:
            usage = "%prog " + usage
        super().__init__(
            usage=usage,
            description=description,
        )
        self.set_defaults(action=action)
        self.add_options(options)
        self.cmd = action

    def __eq__(self, other: str) -> bool:       # type: ignore[override]
        # A convenience equality, so that I can put strings in unit test
        # results, and they will compare equal to objects.
        return (other == f"<CmdOptionParser:{self.cmd}>")

    __hash__ = None         # type: ignore[assignment]

    def get_prog_name(self) -> str:
        """Override of an undocumented function in optparse.OptionParser."""
        program_name = super().get_prog_name()

        # Include the sub-command for this parser as part of the command.
        return f"{program_name} {self.cmd}"

# In lists of Opts, keep them alphabetized by the option names as they appear
# on the command line, since these lists determine the order of the options in
# the help output.
#
# In COMMANDS, keep the keys (command names) alphabetized.

GLOBAL_ARGS = [
    Opts.debug,
    Opts.help,
    Opts.rcfile,
]

COMMANDS = {
    "annotate": CmdOptionParser(
        "annotate",
        [
            Opts.directory,
            Opts.datafle_input,
            Opts.ignore_errors,
            Opts.include,
            Opts.omit,
            ] + GLOBAL_ARGS,
        usage="[options] [modules]",
        description=(
            "Make annotated copies of the given files, marking statements that are executed " +
            "with > and statements that are missed with !."
        ),
    ),

    "combine": CmdOptionParser(
        "combine",
        [
            Opts.append,
            Opts.datafile,
            Opts.keep,
            Opts.quiet,
            ] + GLOBAL_ARGS,
        usage="[options] <path1> <path2> ... <pathN>",
        description=(
            "Combine data from multiple coverage files. " +
            "The combined results are written to a single " +
            "file representing the union of the data. The positional " +
            "arguments are data files or directories containing data files. " +
            "If no paths are provided, data files in the default data file's " +
            "directory are combined."
        ),
    ),

    "debug": CmdOptionParser(
        "debug", GLOBAL_ARGS,
        usage="<topic>",
        description=(
            "Display information about the internals of coverage.py, " +
            "for diagnosing problems. " +
            "Topics are: " +
                "'data' to show a summary of the collected data; " +
                "'sys' to show installation information; " +
                "'config' to show the configuration; " +
                "'premain' to show what is calling coverage; " +
                "'pybehave' to show internal flags describing Python behavior."
        ),
    ),

    "erase": CmdOptionParser(
        "erase",
        [
            Opts.datafile
            ] + GLOBAL_ARGS,
        description="Erase previously collected coverage data.",
    ),

    "help": CmdOptionParser(
        "help", GLOBAL_ARGS,
        usage="[command]",
        description="Describe how to use coverage.py",
    ),

    "html": CmdOptionParser(
        "html",
        [
            Opts.contexts,
            Opts.directory,
            Opts.datafle_input,
            Opts.fail_under,
            Opts.ignore_errors,
            Opts.include,
            Opts.omit,
            Opts.precision,
            Opts.quiet,
            Opts.show_contexts,
            Opts.skip_covered,
            Opts.no_skip_covered,
            Opts.skip_empty,
            Opts.title,
            ] + GLOBAL_ARGS,
        usage="[options] [modules]",
        description=(
            "Create an HTML report of the coverage of the files.  " +
            "Each file gets its own page, with the source decorated to show " +
            "executed, excluded, and missed lines."
        ),
    ),

    "json": CmdOptionParser(
        "json",
        [
            Opts.contexts,
            Opts.datafle_input,
            Opts.fail_under,
            Opts.ignore_errors,
            Opts.include,
            Opts.omit,
            Opts.output_json,
            Opts.json_pretty_print,
            Opts.quiet,
            Opts.show_contexts,
            ] + GLOBAL_ARGS,
        usage="[options] [modules]",
        description="Generate a JSON report of coverage results.",
    ),

    "lcov": CmdOptionParser(
        "lcov",
        [
            Opts.datafle_input,
            Opts.fail_under,
            Opts.ignore_errors,
            Opts.include,
            Opts.output_lcov,
            Opts.omit,
            Opts.quiet,
            ] + GLOBAL_ARGS,
        usage="[options] [modules]",
        description="Generate an LCOV report of coverage results.",
    ),

    "report": CmdOptionParser(
        "report",
        [
            Opts.contexts,
            Opts.datafle_input,
            Opts.fail_under,
            Opts.format,
            Opts.ignore_errors,
            Opts.include,
            Opts.omit,
            Opts.precision,
            Opts.sort,
            Opts.show_missing,
            Opts.skip_covered,
            Opts.no_skip_covered,
            Opts.skip_empty,
            ] + GLOBAL_ARGS,
        usage="[options] [modules]",
        description="Report coverage statistics on modules.",
    ),

    "run": CmdOptionParser(
        "run",
        [
            Opts.append,
            Opts.branch,
            Opts.concurrency,
            Opts.context,
            Opts.datafile_output,
            Opts.include,
            Opts.module,
            Opts.omit,
            Opts.pylib,
            Opts.parallel_mode,
            Opts.source,
            Opts.timid,
            ] + GLOBAL_ARGS,
        usage="[options] <pyfile> [program options]",
        description="Run a Python program, measuring code execution.",
    ),

    "xml": CmdOptionParser(
        "xml",
        [
            Opts.datafle_input,
            Opts.fail_under,
            Opts.ignore_errors,
            Opts.include,
            Opts.omit,
            Opts.output_xml,
            Opts.quiet,
            Opts.skip_empty,
            ] + GLOBAL_ARGS,
        usage="[options] [modules]",
        description="Generate an XML report of coverage results.",
    ),
}


def show_help(
    error: Optional[str] = None,
    topic: Optional[str] = None,
    parser: Optional[optparse.OptionParser] = None,
) -> None:
    """Display an error message, or the named topic."""
    assert error or topic or parser

    program_path = sys.argv[0]
    if program_path.endswith(os.path.sep + "__main__.py"):
        # The path is the main module of a package; get that path instead.
        program_path = os.path.dirname(program_path)
    program_name = os.path.basename(program_path)
    if env.WINDOWS:
        # entry_points={"console_scripts":...} on Windows makes files
        # called coverage.exe, coverage3.exe, and coverage-3.5.exe. These
        # invoke coverage-script.py, coverage3-script.py, and
        # coverage-3.5-script.py.  argv[0] is the .py file, but we want to
        # get back to the original form.
        auto_suffix = "-script.py"
        if program_name.endswith(auto_suffix):
            program_name = program_name[:-len(auto_suffix)]

    help_params = dict(coverage.__dict__)
    help_params["__url__"] = __url__
    help_params["program_name"] = program_name
    if HAS_CTRACER:
        help_params["extension_modifier"] = "with C extension"
    else:
        help_params["extension_modifier"] = "without C extension"

    if error:
        print(error, file=sys.stderr)
        print(f"Use '{program_name} help' for help.", file=sys.stderr)
    elif parser:
        print(parser.format_help().strip())
        print()
    else:
        assert topic is not None
        help_msg = textwrap.dedent(HELP_TOPICS.get(topic, "")).strip()
        if help_msg:
            print(help_msg.format(**help_params))
        else:
            print(f"Don't know topic {topic!r}")
    print("Full documentation is at {__url__}".format(**help_params))


OK, ERR, FAIL_UNDER = 0, 1, 2


class CoverageScript:
    """The command-line interface to coverage.py."""

    def __init__(self) -> None:
        self.global_option = False
        self.coverage: Coverage

    def command_line(self, argv: List[str]) -> int:
        """The bulk of the command line interface to coverage.py.

        `argv` is the argument list to process.

        Returns 0 if all is well, 1 if something went wrong.

        """
        # Collect the command-line options.
        if not argv:
            show_help(topic="minimum_help")
            return OK

        # The command syntax we parse depends on the first argument.  Global
        # switch syntax always starts with an option.
        parser: Optional[optparse.OptionParser]
        self.global_option = argv[0].startswith("-")
        if self.global_option:
            parser = GlobalOptionParser()
        else:
            parser = COMMANDS.get(argv[0])
            if not parser:
                show_help(f"Unknown command: {argv[0]!r}")
                return ERR
            argv = argv[1:]

        ok, options, args = parser.parse_args_ok(argv)
        if not ok:
            return ERR
        assert options is not None

        # Handle help and version.
        if self.do_help(options, args, parser):
            return OK

        # Listify the list options.
        source = unshell_list(options.source)
        omit = unshell_list(options.omit)
        include = unshell_list(options.include)
        debug = unshell_list(options.debug)
        contexts = unshell_list(options.contexts)

        # Do something.
        self.coverage = Coverage(
            data_file=options.data_file or DEFAULT_DATAFILE,
            data_suffix=options.parallel_mode,
            cover_pylib=options.pylib,
            timid=options.timid,
            branch=options.branch,
            config_file=options.rcfile,
            source=source,
            omit=omit,
            include=include,
            debug=debug,
            concurrency=options.concurrency,
            check_preimported=True,
            context=options.context,
            messages=not options.quiet,
        )

        if options.action == "debug":
            return self.do_debug(args)

        elif options.action == "erase":
            self.coverage.erase()
            return OK

        elif options.action == "run":
            return self.do_run(options, args)

        elif options.action == "combine":
            if options.append:
                self.coverage.load()
            data_paths = args or None
            self.coverage.combine(data_paths, strict=True, keep=bool(options.keep))
            self.coverage.save()
            return OK

        # Remaining actions are reporting, with some common options.
        report_args = dict(
            morfs=unglob_args(args),
            ignore_errors=options.ignore_errors,
            omit=omit,
            include=include,
            contexts=contexts,
        )

        # We need to be able to import from the current directory, because
        # plugins may try to, for example, to read Django settings.
        sys.path.insert(0, "")

        self.coverage.load()

        total = None
        if options.action == "report":
            total = self.coverage.report(
                precision=options.precision,
                show_missing=options.show_missing,
                skip_covered=options.skip_covered,
                skip_empty=options.skip_empty,
                sort=options.sort,
                output_format=options.format,
                **report_args
            )
        elif options.action == "annotate":
            self.coverage.annotate(directory=options.directory, **report_args)
        elif options.action == "html":
            total = self.coverage.html_report(
                directory=options.directory,
                precision=options.precision,
                skip_covered=options.skip_covered,
                skip_empty=options.skip_empty,
                show_contexts=options.show_contexts,
                title=options.title,
                **report_args
            )
        elif options.action == "xml":
            total = self.coverage.xml_report(
                outfile=options.outfile,
                skip_empty=options.skip_empty,
                **report_args
            )
        elif options.action == "json":
            total = self.coverage.json_report(
                outfile=options.outfile,
                pretty_print=options.pretty_print,
                show_contexts=options.show_contexts,
                **report_args
            )
        elif options.action == "lcov":
            total = self.coverage.lcov_report(
                outfile=options.outfile,
                **report_args
            )
        else:
            # There are no other possible actions.
            raise AssertionError

        if total is not None:
            # Apply the command line fail-under options, and then use the config
            # value, so we can get fail_under from the config file.
            if options.fail_under is not None:
                self.coverage.set_option("report:fail_under", options.fail_under)
            if options.precision is not None:
                self.coverage.set_option("report:precision", options.precision)

            fail_under = cast(float, self.coverage.get_option("report:fail_under"))
            precision = cast(int, self.coverage.get_option("report:precision"))
            if should_fail_under(total, fail_under, precision):
                msg = "total of {total} is less than fail-under={fail_under:.{p}f}".format(
                    total=Numbers(precision=precision).display_covered(total),
                    fail_under=fail_under,
                    p=precision,
                )
                print("Coverage failure:", msg)
                return FAIL_UNDER

        return OK

    def do_help(
        self,
        options: optparse.Values,
        args: List[str],
        parser: optparse.OptionParser,
    ) -> bool:
        """Deal with help requests.

        Return True if it handled the request, False if not.

        """
        # Handle help.
        if options.help:
            if self.global_option:
                show_help(topic="help")
            else:
                show_help(parser=parser)
            return True

        if options.action == "help":
            if args:
                for a in args:
                    parser_maybe = COMMANDS.get(a)
                    if parser_maybe is not None:
                        show_help(parser=parser_maybe)
                    else:
                        show_help(topic=a)
            else:
                show_help(topic="help")
            return True

        # Handle version.
        if options.version:
            show_help(topic="version")
            return True

        return False

    def do_run(self, options: optparse.Values, args: List[str]) -> int:
        """Implementation of 'coverage run'."""

        if not args:
            if options.module:
                # Specified -m with nothing else.
                show_help("No module specified for -m")
                return ERR
            command_line = cast(str, self.coverage.get_option("run:command_line"))
            if command_line is not None:
                args = shlex.split(command_line)
                if args and args[0] in {"-m", "--module"}:
                    options.module = True
                    args = args[1:]
        if not args:
            show_help("Nothing to do.")
            return ERR

        if options.append and self.coverage.get_option("run:parallel"):
            show_help("Can't append to data files in parallel mode.")
            return ERR

        if options.concurrency == "multiprocessing":
            # Can't set other run-affecting command line options with
            # multiprocessing.
            for opt_name in ["branch", "include", "omit", "pylib", "source", "timid"]:
                # As it happens, all of these options have no default, meaning
                # they will be None if they have not been specified.
                if getattr(options, opt_name) is not None:
                    show_help(
                        "Options affecting multiprocessing must only be specified " +
                        "in a configuration file.\n" +
                        f"Remove --{opt_name} from the command line."
                    )
                    return ERR

        os.environ["COVERAGE_RUN"] = "true"

        runner = PyRunner(args, as_module=bool(options.module))
        runner.prepare()

        if options.append:
            self.coverage.load()

        # Run the script.
        self.coverage.start()
        code_ran = True
        try:
            runner.run()
        except NoSource:
            code_ran = False
            raise
        finally:
            self.coverage.stop()
            if code_ran:
                self.coverage.save()

        return OK

    def do_debug(self, args: List[str]) -> int:
        """Implementation of 'coverage debug'."""

        if not args:
            show_help("What information would you like: config, data, sys, premain, pybehave?")
            return ERR
        if args[1:]:
            show_help("Only one topic at a time, please")
            return ERR

        if args[0] == "sys":
            write_formatted_info(print, "sys", self.coverage.sys_info())
        elif args[0] == "data":
            print(info_header("data"))
            data_file = self.coverage.config.data_file
            debug_data_file(data_file)
            for filename in combinable_files(data_file):
                print("-----")
                debug_data_file(filename)
        elif args[0] == "config":
            write_formatted_info(print, "config", self.coverage.config.debug_info())
        elif args[0] == "premain":
            print(info_header("premain"))
            print(short_stack(full=True))
        elif args[0] == "pybehave":
            write_formatted_info(print, "pybehave", env.debug_info())
        else:
            show_help(f"Don't know what you mean by {args[0]!r}")
            return ERR

        return OK


def unshell_list(s: str) -> Optional[List[str]]:
    """Turn a command-line argument into a list."""
    if not s:
        return None
    if env.WINDOWS:
        # When running coverage.py as coverage.exe, some of the behavior
        # of the shell is emulated: wildcards are expanded into a list of
        # file names.  So you have to single-quote patterns on the command
        # line, but (not) helpfully, the single quotes are included in the
        # argument, so we have to strip them off here.
        s = s.strip("'")
    return s.split(",")


def unglob_args(args: List[str]) -> List[str]:
    """Interpret shell wildcards for platforms that need it."""
    if env.WINDOWS:
        globbed = []
        for arg in args:
            if "?" in arg or "*" in arg:
                globbed.extend(glob.glob(arg))
            else:
                globbed.append(arg)
        args = globbed
    return args


HELP_TOPICS = {
    "help": """\
        Coverage.py, version {__version__} {extension_modifier}
        Measure, collect, and report on code coverage in Python programs.

        usage: {program_name} <command> [options] [args]

        Commands:
            annotate    Annotate source files with execution information.
            combine     Combine a number of data files.
            debug       Display information about the internals of coverage.py
            erase       Erase previously collected coverage data.
            help        Get help on using coverage.py.
            html        Create an HTML report.
            json        Create a JSON report of coverage results.
            lcov        Create an LCOV report of coverage results.
            report      Report coverage stats on modules.
            run         Run a Python program and measure code execution.
            xml         Create an XML report of coverage results.

        Use "{program_name} help <command>" for detailed help on any command.
    """,

    "minimum_help": (
        "Code coverage for Python, version {__version__} {extension_modifier}.  " +
        "Use '{program_name} help' for help."
    ),

    "version": "Coverage.py, version {__version__} {extension_modifier}",
}


def main(argv: Optional[List[str]] = None) -> Optional[int]:
    """The main entry point to coverage.py.

    This is installed as the script entry point.

    """
    if argv is None:
        argv = sys.argv[1:]
    try:
        status = CoverageScript().command_line(argv)
    except _ExceptionDuringRun as err:
        # An exception was caught while running the product code.  The
        # sys.exc_info() return tuple is packed into an _ExceptionDuringRun
        # exception.
        traceback.print_exception(*err.args)    # pylint: disable=no-value-for-parameter
        status = ERR
    except _BaseCoverageException as err:
        # A controlled error inside coverage.py: print the message to the user.
        msg = err.args[0]
        print(msg)
        status = ERR
    except SystemExit as err:
        # The user called `sys.exit()`.  Exit with their argument, if any.
        if err.args:
            status = err.args[0]
        else:
            status = None
    return status

# Profiling using ox_profile.  Install it from GitHub:
#   pip install git+https://github.com/emin63/ox_profile.git
#
# $set_env.py: COVERAGE_PROFILE - Set to use ox_profile.
_profile = os.getenv("COVERAGE_PROFILE")
if _profile:                                                # pragma: debugging
    from ox_profile.core.launchers import SimpleLauncher    # pylint: disable=import-error
    original_main = main

    def main(                                               # pylint: disable=function-redefined
        argv: Optional[List[str]] = None,
    ) -> Optional[int]:
        """A wrapper around main that profiles."""
        profiler = SimpleLauncher.launch()
        try:
            return original_main(argv)
        finally:
            data, _ = profiler.query(re_filter="coverage", max_records=100)
            print(profiler.show(query=data, limit=100, sep="", col=""))
            profiler.cancel()