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# Source code for astropy.config.configuration

    # Licensed under a 3-clause BSD style license - see LICENSE.rst
    """This module contains classes and functions to standardize access to
    configuration files for Astropy and affiliated packages.

    .. note::
        The configuration system makes use of the 'configobj' package, which stores
        configuration in a text format like that used in the standard library
        `ConfigParser`. More information and documentation for configobj can be
        found at https://configobj.readthedocs.io .
    """

    import contextlib
    import importlib
    import io
    import os
    import pkgutil
    import warnings
    from contextlib import contextmanager, nullcontext
    from os import path
    from textwrap import TextWrapper
    from warnings import warn

    import configobj, validate
    from astropy.utils import find_current_module, silence
    from astropy.utils.decorators import deprecated
    from astropy.utils.exceptions import AstropyDeprecationWarning, AstropyWarning
    from astropy.utils.introspection import resolve_name

    from .paths import get_config_dir

    __all__ = (
        "InvalidConfigurationItemWarning",
        "ConfigurationMissingWarning",
        "get_config",
        "reload_config",
        "ConfigNamespace",
        "ConfigItem",
        "generate_config",
        "create_config_file",
    )

    class InvalidConfigurationItemWarning(AstropyWarning):
        """A Warning that is issued when the configuration value specified in the
        astropy configuration file does not match the type expected for that
        configuration value.
        """

    # This was raised with Astropy < 4.3 when the configuration file was not found.
    # It is kept for compatibility and should be removed at some point.
    @deprecated("5.0")
    class ConfigurationMissingWarning(AstropyWarning):
        """A Warning that is issued when the configuration directory cannot be
        accessed (usually due to a permissions problem). If this warning appears,
        configuration items will be set to their defaults rather than read from the
        configuration file, and no configuration will persist across sessions.
        """

    # these are not in __all__ because it's not intended that a user ever see them
    class ConfigurationDefaultMissingError(ValueError):
        """An exception that is raised when the configuration defaults (which
        should be generated at build-time) are missing.
        """

    # this is used in astropy/__init__.py
    class ConfigurationDefaultMissingWarning(AstropyWarning):
        """A warning that is issued when the configuration defaults (which
        should be generated at build-time) are missing.
        """

    class ConfigurationChangedWarning(AstropyWarning):
        """
        A warning that the configuration options have changed.
        """

    class _ConfigNamespaceMeta(type):
        def __init__(cls, name, bases, dict):
            if cls.__bases__[0] is object:
                return

            for key, val in dict.items():
                if isinstance(val, ConfigItem):
                    val.name = key

    class ConfigNamespace(metaclass=_ConfigNamespaceMeta):
        """
        A namespace of configuration items.  Each subpackage with
        configuration items should define a subclass of this class,
        containing `ConfigItem` instances as members.

        For example::

            class Conf(_config.ConfigNamespace):
                unicode_output = _config.ConfigItem(
                    False,
                    'Use Unicode characters when outputting values, ...')
                use_color = _config.ConfigItem(
                    sys.platform != 'win32',
                    'When True, use ANSI color escape sequences when ...',
                    aliases=['astropy.utils.console.USE_COLOR'])
            conf = Conf()
        """

        def __iter__(self):
            for key, val in self.__class__.__dict__.items():
                if isinstance(val, ConfigItem):
                    yield key

        keys = __iter__
        """Iterate over configuration item names."""

        def values(self):
            """Iterate over configuration item values."""
            for val in self.__class__.__dict__.values():
                if isinstance(val, ConfigItem):
                    yield val

        def items(self):
            """Iterate over configuration item ``(name, value)`` pairs."""
            for key, val in self.__class__.__dict__.items():
                if isinstance(val, ConfigItem):
                    yield key, val

        def set_temp(self, attr, value):
            """
            Temporarily set a configuration value.

            Parameters
            ----------
            attr : str
                Configuration item name

            value : object
                The value to set temporarily.

            Examples
            --------
            >>> import astropy
            >>> with astropy.conf.set_temp('use_color', False):
            ...     pass
            ...     # console output will not contain color
            >>> # console output contains color again...
            """
            if hasattr(self, attr):
                return self.__class__.__dict__[attr].set_temp(value)
            raise AttributeError(f"No configuration parameter '{attr}'")

        def reload(self, attr=None):
            """
            Reload a configuration item from the configuration file.

            Parameters
            ----------
            attr : str, optional
                The name of the configuration parameter to reload.  If not
                provided, reload all configuration parameters.
            """
            if attr is not None:
                if hasattr(self, attr):
                    return self.__class__.__dict__[attr].reload()
                raise AttributeError(f"No configuration parameter '{attr}'")

            for item in self.values():
                item.reload()

        def reset(self, attr=None):
            """
            Reset a configuration item to its default.

            Parameters
            ----------
            attr : str, optional
                The name of the configuration parameter to reload.  If not
                provided, reset all configuration parameters.
            """
            if attr is not None:
                if hasattr(self, attr):
                    prop = self.__class__.__dict__[attr]
                    prop.set(prop.defaultvalue)
                    return
                raise AttributeError(f"No configuration parameter '{attr}'")

            for item in self.values():
                item.set(item.defaultvalue)

    class ConfigItem:
        """
        A setting and associated value stored in a configuration file.

        These objects should be created as members of
        `ConfigNamespace` subclasses, for example::

            class _Conf(config.ConfigNamespace):
                unicode_output = config.ConfigItem(
                    False,
                    'Use Unicode characters when outputting values, and writing widgets '
                    'to the console.')
            conf = _Conf()

        Parameters
        ----------
        defaultvalue : object, optional
            The default value for this item. If this is a list of strings, this
            item will be interpreted as an 'options' value - this item must be one
            of those values, and the first in the list will be taken as the default
            value.

        description : str or None, optional
            A description of this item (will be shown as a comment in the
            configuration file)

        cfgtype : str or None, optional
            A type specifier like those used as the *values* of a particular key
            in a ``configspec`` file of ``configobj``. If None, the type will be
            inferred from the default value.

        module : str or None, optional
            The full module name that this item is associated with. The first
            element (e.g. 'astropy' if this is 'astropy.config.configuration')
            will be used to determine the name of the configuration file, while
            the remaining items determine the section. If None, the package will be
            inferred from the package within which this object's initializer is
            called.

        aliases : str, or list of str, optional
            The deprecated location(s) of this configuration item.  If the
            config item is not found at the new location, it will be
            searched for at all of the old locations.

        Raises
        ------
        RuntimeError
            If ``module`` is `None`, but the module this item is created from
            cannot be determined.
        """

        # this is used to make validation faster so a Validator object doesn't
        # have to be created every time
        _validator = validate.Validator()
        cfgtype = None
        """
        A type specifier like those used as the *values* of a particular key in a
        ``configspec`` file of ``configobj``.
        """

        rootname = "astropy"
        """
        Rootname sets the base path for all config files.
        """

        def __init__(
            self, defaultvalue="", description=None, cfgtype=None, module=None, aliases=None
        ):
            from astropy.utils import isiterable

            if module is None:
                module = find_current_module(2)
                if module is None:
                    msg1 = "Cannot automatically determine get_config module, "
                    msg2 = "because it is not called from inside a valid module"
                    raise RuntimeError(msg1 + msg2)
                else:
                    module = module.__name__

            self.module = module
            self.description = description
            self.__doc__ = description

            # now determine cfgtype if it is not given
            if cfgtype is None:
                if isiterable(defaultvalue) and not isinstance(defaultvalue, str):
                    # it is an options list
                    dvstr = [str(v) for v in defaultvalue]
                    cfgtype = "option(" + ", ".join(dvstr) + ")"
                    defaultvalue = dvstr[0]
                elif isinstance(defaultvalue, bool):
                    cfgtype = "boolean"
                elif isinstance(defaultvalue, int):
                    cfgtype = "integer"
                elif isinstance(defaultvalue, float):
                    cfgtype = "float"
                elif isinstance(defaultvalue, str):
                    cfgtype = "string"
                    defaultvalue = str(defaultvalue)

            self.cfgtype = cfgtype

            self._validate_val(defaultvalue)
            self.defaultvalue = defaultvalue

            if aliases is None:
                self.aliases = []
            elif isinstance(aliases, str):
                self.aliases = [aliases]
            else:
                self.aliases = aliases

        def __set__(self, obj, value):
            return self.set(value)

        def __get__(self, obj, objtype=None):
            if obj is None:
                return self
            return self()

        def set(self, value):
            """
            Sets the current value of this ``ConfigItem``.

            This also updates the comments that give the description and type
            information.

            Parameters
            ----------
            value
                The value this item should be set to.

            Raises
            ------
            TypeError
                If the provided ``value`` is not valid for this ``ConfigItem``.
            """
            try:
                value = self._validate_val(value)
            except validate.ValidateError as e:
                raise TypeError(
                    f"Provided value for configuration item {self.name} not valid:"
                    f" {e.args[0]}"
                )

            sec = get_config(self.module, rootname=self.rootname)

            sec[self.name] = value

        @contextmanager
        def set_temp(self, value):
            """
            Sets this item to a specified value only inside a with block.

            Use as::

                ITEM = ConfigItem('ITEM', 'default', 'description')

                with ITEM.set_temp('newval'):
                    #... do something that wants ITEM's value to be 'newval' ...
                    print(ITEM)

                # ITEM is now 'default' after the with block

            Parameters
            ----------
            value
                The value to set this item to inside the with block.

            """
            initval = self()
            self.set(value)
            try:
                yield
            finally:
                self.set(initval)

        def reload(self):
            """Reloads the value of this ``ConfigItem`` from the relevant
            configuration file.

            Returns
            -------
            val : object
                The new value loaded from the configuration file.

            """
            self.set(self.defaultvalue)
            baseobj = get_config(self.module, True, rootname=self.rootname)
            secname = baseobj.name

            cobj = baseobj
            # a ConfigObj's parent is itself, so we look for the parent with that
            while cobj.parent is not cobj:
                cobj = cobj.parent

            newobj = configobj.ConfigObj(cobj.filename, interpolation=False)
            if secname is not None:
                if secname not in newobj:
                    return baseobj.get(self.name)
                newobj = newobj[secname]

            if self.name in newobj:
                baseobj[self.name] = newobj[self.name]
            return baseobj.get(self.name)

        def __repr__(self):
            return (
                f"<{self.__class__.__name__}: name={self.name!r} value={self()!r} at"
                f" 0x{id(self):x}>"
            )

        def __str__(self):
            return "\n".join(
                (
                    f"{self.__class__.__name__}: {self.name}",
                    f"  cfgtype={self.cfgtype!r}",
                    f"  defaultvalue={self.defaultvalue!r}",
                    f"  description={self.description!r}",
                    f"  module={self.module}",
                    f"  value={self()!r}",
                )
            )

        def __call__(self):
            """Returns the value of this ``ConfigItem``

            Returns
            -------
            val : object
                This item's value, with a type determined by the ``cfgtype``
                attribute.

            Raises
            ------
            TypeError
                If the configuration value as stored is not this item's type.

            """

            def section_name(section):
                if section == "":
                    return "at the top-level"
                else:
                    return f"in section [{section}]"

            options = []
            sec = get_config(self.module, rootname=self.rootname)
            if self.name in sec:
                options.append((sec[self.name], self.module, self.name))

            for alias in self.aliases:
                module, name = alias.rsplit(".", 1)
                sec = get_config(module, rootname=self.rootname)
                if "." in module:
                    filename, module = module.split(".", 1)
                else:
                    filename = module
                    module = ""
                if name in sec:
                    if "." in self.module:
                        new_module = self.module.split(".", 1)[1]
                    else:
                        new_module = ""
                    warn(
                        f"Config parameter '{name}' {section_name(module)} of the file"
                        f" '{get_config_filename(filename, rootname=self.rootname)}' is"
                        f" deprecated. Use '{self.name}'"
                        f" {section_name(new_module)} instead.",
                        AstropyDeprecationWarning,
                    )
                    options.append((sec[name], module, name))

            if len(options) == 0:
                self.set(self.defaultvalue)
                options.append((self.defaultvalue, None, None))

            if len(options) > 1:
                filename, sec = self.module.split(".", 1)
                warn(
                    f"Config parameter '{self.name}' {section_name(sec)} of the file"
                    f" '{get_config_filename(filename, rootname=self.rootname)}' is given"
                    " by more than one alias"
                    f" ({', '.join(['.'.join(x[1:3]) for x in options if x[1] is not None])})."
                    " Using the first.",
                    AstropyDeprecationWarning,
                )

            val = options[0][0]

            try:
                return self._validate_val(val)
            except validate.ValidateError as e:
                raise TypeError(f"Configuration value not valid: {e.args[0]}")

        def _validate_val(self, val):
            """Validates the provided value based on cfgtype and returns the
            type-cast value

            throws the underlying configobj exception if it fails
            """
            # note that this will normally use the *class* attribute `_validator`,
            # but if some arcane reason is needed for making a special one for an
            # instance or sub-class, it will be used
            return self._validator.check(self.cfgtype, val)

    # this dictionary stores the primary copy of the ConfigObj's for each
    # root package
    _cfgobjs = {}

    def get_config_filename(packageormod=None, rootname=None):
        """
        Get the filename of the config file associated with the given
        package or module.
        """
        cfg = get_config(packageormod, rootname=rootname)
        while cfg.parent is not cfg:
            cfg = cfg.parent
        return cfg.filename

    # This is used by testing to override the config file, so we can test
    # with various config files that exercise different features of the
    # config system.
    _override_config_file = None

    def get_config(packageormod=None, reload=False, rootname=None):
        """Gets the configuration object or section associated with a particular
        package or module.

        Parameters
        ----------
        packageormod : str or None
            The package for which to retrieve the configuration object. If a
            string, it must be a valid package name, or if ``None``, the package from
            which this function is called will be used.

        reload : bool, optional
            Reload the file, even if we have it cached.

        rootname : str or None
            Name of the root configuration directory. If ``None`` and
            ``packageormod`` is ``None``, this defaults to be the name of
            the package from which this function is called. If ``None`` and
            ``packageormod`` is not ``None``, this defaults to ``astropy``.

        Returns
        -------
        cfgobj : ``configobj.ConfigObj`` or ``configobj.Section``
            If the requested package is a base package, this will be the
            ``configobj.ConfigObj`` for that package, or if it is a subpackage or
            module, it will return the relevant ``configobj.Section`` object.

        Raises
        ------
        RuntimeError
            If ``packageormod`` is `None`, but the package this item is created
            from cannot be determined.
        """

        if packageormod is None:
            packageormod = find_current_module(2)
            if packageormod is None:
                msg1 = "Cannot automatically determine get_config module, "
                msg2 = "because it is not called from inside a valid module"
                raise RuntimeError(msg1 + msg2)
            else:
                packageormod = packageormod.__name__

            _autopkg = True

        else:
            _autopkg = False

        packageormodspl = packageormod.split(".")
        pkgname = packageormodspl[0]
        secname = ".".join(packageormodspl[1:])

        if rootname is None:
            if _autopkg:
                rootname = pkgname
            else:
                rootname = "astropy"  # so we don't break affiliated packages

        cobj = _cfgobjs.get(pkgname, None)

        if cobj is None or reload:
            cfgfn = None
            try:
                # This feature is intended only for use by the unit tests
                if _override_config_file is not None:
                    cfgfn = _override_config_file
                else:
                    cfgfn = path.join(get_config_dir(rootname=rootname), pkgname + ".cfg")
                cobj = configobj.ConfigObj(cfgfn, interpolation=False)
            except OSError:
                # This can happen when HOME is not set
                cobj = configobj.ConfigObj(interpolation=False)

            # This caches the object, so if the file becomes accessible, this
            # function won't see it unless the module is reloaded
            _cfgobjs[pkgname] = cobj

        if secname:  # not the root package
            if secname not in cobj:
                cobj[secname] = {}
            return cobj[secname]
        else:
            return cobj

    def generate_config(pkgname="astropy", filename=None, verbose=False):
        """Generates a configuration file, from the list of `ConfigItem`
        objects for each subpackage.

        .. versionadded:: 4.1

        Parameters
        ----------
        pkgname : str or None
            The package for which to retrieve the configuration object.
        filename : str or file-like or None
            If None, the default configuration path is taken from `get_config`.

        """
        if verbose:
            verbosity = nullcontext
            filter_warnings = AstropyDeprecationWarning
        else:
            verbosity = silence
            filter_warnings = Warning

        package = importlib.import_module(pkgname)
        with verbosity(), warnings.catch_warnings():
            warnings.simplefilter("ignore", category=filter_warnings)
            for mod in pkgutil.walk_packages(
                path=package.__path__, prefix=package.__name__ + "."
            ):
                if mod.module_finder.path.endswith(("test", "tests")) or mod.name.endswith(
                    "setup_package"
                ):
                    # Skip test and setup_package modules
                    continue
                if mod.name.split(".")[-1].startswith("_"):
                    # Skip private modules
                    continue

                with contextlib.suppress(ImportError):
                    importlib.import_module(mod.name)

        wrapper = TextWrapper(initial_indent="## ", subsequent_indent="## ", width=78)

        if filename is None:
            filename = get_config_filename(pkgname)

        with contextlib.ExitStack() as stack:
            if isinstance(filename, (str, os.PathLike)):
                fp = stack.enter_context(open(filename, "w"))
            else:
                # assume it's a file object, or io.StringIO
                fp = filename

            # Parse the subclasses, ordered by their module name
            subclasses = ConfigNamespace.__subclasses__()
            processed = set()

            for conf in sorted(subclasses, key=lambda x: x.__module__):
                mod = conf.__module__

                # Skip modules for other packages, e.g. astropy modules that
                # would be imported when running the function for astroquery.
                if mod.split(".")[0] != pkgname:
                    continue

                # Check that modules are not processed twice, which can happen
                # when they are imported in another module.
                if mod in processed:
                    continue
                else:
                    processed.add(mod)

                print_module = True
                for item in conf().values():
                    if print_module:
                        # If this is the first item of the module, we print the
                        # module name, but not if this is the root package...
                        if item.module != pkgname:
                            modname = item.module.replace(f"{pkgname}.", "")
                            fp.write(f"[{modname}]\n\n")
                        print_module = False

                    fp.write(wrapper.fill(item.description) + "\n")
                    if isinstance(item.defaultvalue, (tuple, list)):
                        if len(item.defaultvalue) == 0:
                            fp.write(f"# {item.name} = ,\n\n")
                        elif len(item.defaultvalue) == 1:
                            fp.write(f"# {item.name} = {item.defaultvalue[0]},\n\n")
                        else:
                            fp.write(
                                f"# {item.name} ="
                                f' {",".join(map(str, item.defaultvalue))}\n\n'
                            )
                    else:
                        fp.write(f"# {item.name} = {item.defaultvalue}\n\n")

    def reload_config(packageormod=None, rootname=None):
        """Reloads configuration settings from a configuration file for the root
        package of the requested package/module.

        This overwrites any changes that may have been made in `ConfigItem`
        objects.  This applies for any items that are based on this file, which
        is determined by the *root* package of ``packageormod``
        (e.g. ``'astropy.cfg'`` for the ``'astropy.config.configuration'``
        module).

        Parameters
        ----------
        packageormod : str or None
            The package or module name - see `get_config` for details.
        rootname : str or None
            Name of the root configuration directory - see `get_config`
            for details.
        """
        sec = get_config(packageormod, True, rootname=rootname)
        # look for the section that is its own parent - that's the base object
        while sec.parent is not sec:
            sec = sec.parent
        sec.reload()

    def is_unedited_config_file(content, template_content=None):
        """
        Determines if a config file can be safely replaced because it doesn't
        actually contain any meaningful content, i.e. if it contains only comments
        or is completely empty.
        """
        buffer = io.StringIO(content)
        raw_cfg = configobj.ConfigObj(buffer, interpolation=True)
        # If any of the items is set, return False
        return not any(len(v) > 0 for v in raw_cfg.values())

    # This function is no more used by astropy but it is kept for the other
    # packages that may use it (e.g. astroquery). It should be removed at some
    # point.
    # this is not in __all__ because it's not intended that a user uses it
    @deprecated("5.0")
    def update_default_config(pkg, default_cfg_dir_or_fn, version=None, rootname="astropy"):
        """
        Checks if the configuration file for the specified package exists,
        and if not, copy over the default configuration.  If the
        configuration file looks like it has already been edited, we do
        not write over it, but instead write a file alongside it named
        ``pkg.version.cfg`` as a "template" for the user.

        Parameters
        ----------
        pkg : str
            The package to be updated.
        default_cfg_dir_or_fn : str
            The filename or directory name where the default configuration file is.
            If a directory name, ``'pkg.cfg'`` will be used in that directory.
        version : str, optional
            The current version of the given package.  If not provided, it will
            be obtained from ``pkg.__version__``.
        rootname : str
            Name of the root configuration directory.

        Returns
        -------
        updated : bool
            If the profile was updated, `True`, otherwise `False`.

        Raises
        ------
        AttributeError
            If the version number of the package could not determined.

        """

        if path.isdir(default_cfg_dir_or_fn):
            default_cfgfn = path.join(default_cfg_dir_or_fn, pkg + ".cfg")
        else:
            default_cfgfn = default_cfg_dir_or_fn

        if not path.isfile(default_cfgfn):
            # There is no template configuration file, which basically
            # means the affiliated package is not using the configuration
            # system, so just return.
            return False

        cfgfn = get_config(pkg, rootname=rootname).filename

        with open(default_cfgfn, encoding="latin-1") as fr:
            template_content = fr.read()

        doupdate = False
        if cfgfn is not None:
            if path.exists(cfgfn):
                with open(cfgfn, encoding="latin-1") as fd:
                    content = fd.read()

                identical = content == template_content

                if not identical:
                    doupdate = is_unedited_config_file(content, template_content)
            elif path.exists(path.dirname(cfgfn)):
                doupdate = True
                identical = False

        if version is None:
            version = resolve_name(pkg, "__version__")

        # Don't install template files for dev versions, or we'll end up
        # spamming `~/.astropy/config`.
        if version and "dev" not in version and cfgfn is not None:
            template_path = path.join(
                get_config_dir(rootname=rootname), f"{pkg}.{version}.cfg"
            )
            needs_template = not path.exists(template_path)
        else:
            needs_template = False

        if doupdate or needs_template:
            if needs_template:
                with open(template_path, "w", encoding="latin-1") as fw:
                    fw.write(template_content)
                # If we just installed a new template file and we can't
                # update the main configuration file because it has user
                # changes, display a warning.
                if not identical and not doupdate:
                    warn(
                        f"The configuration options in {pkg} {version} may have changed, "
                        "your configuration file was not updated in order to "
                        "preserve local changes.  A new configuration template "
                        f"has been saved to '{template_path}'.",
                        ConfigurationChangedWarning,
                    )

            if doupdate and not identical:
                with open(cfgfn, "w", encoding="latin-1") as fw:
                    fw.write(template_content)
                return True

        return False

    def create_config_file(pkg, rootname="astropy", overwrite=False):
        """
        Create the default configuration file for the specified package.
        If the file already exists, it is updated only if it has not been
        modified.  Otherwise the ``overwrite`` flag is needed to overwrite it.

        Parameters
        ----------
        pkg : str
            The package to be updated.
        rootname : str
            Name of the root configuration directory.
        overwrite : bool
            Force updating the file if it already exists.

        Returns
        -------
        updated : bool
            If the profile was updated, `True`, otherwise `False`.

        """

        # local import to prevent using the logger before it is configured
        from astropy.logger import log

        cfgfn = get_config_filename(pkg, rootname=rootname)

        # generate the default config template
        template_content = io.StringIO()
        generate_config(pkg, template_content)
        template_content.seek(0)
        template_content = template_content.read()

        doupdate = True

        # if the file already exists, check that it has not been modified
        if cfgfn is not None and path.exists(cfgfn):
            with open(cfgfn, encoding="latin-1") as fd:
                content = fd.read()

            doupdate = is_unedited_config_file(content, template_content)

        if doupdate or overwrite:
            with open(cfgfn, "w", encoding="latin-1") as fw:
                fw.write(template_content)
            log.info(f"The configuration file has been successfully written to {cfgfn}")
            return True
        elif not doupdate:
            log.warning(
                "The configuration file already exists and seems to "
                "have been customized, so it has not been updated. "
                "Use overwrite=True if you really want to update it."
            )

        return False