view mercurial/thirdparty/attr/setters.py @ 51402:2e10ddbb9faa

phases: check secret presence the right way during discovery

There is an official function for this, lets use it.

This will prevent the code to break in the future while we refactor the phase
code.

# SPDX-License-Identifier: MIT

"""
Commonly used hooks for on_setattr.
"""


from . import _config
from .exceptions import FrozenAttributeError


def pipe(*setters):
    """
    Run all *setters* and return the return value of the last one.

    .. versionadded:: 20.1.0
    """

    def wrapped_pipe(instance, attrib, new_value):
        rv = new_value

        for setter in setters:
            rv = setter(instance, attrib, rv)

        return rv

    return wrapped_pipe


def frozen(_, __, ___):
    """
    Prevent an attribute to be modified.

    .. versionadded:: 20.1.0
    """
    raise FrozenAttributeError()


def validate(instance, attrib, new_value):
    """
    Run *attrib*'s validator on *new_value* if it has one.

    .. versionadded:: 20.1.0
    """
    if _config._run_validators is False:
        return new_value

    v = attrib.validator
    if not v:
        return new_value

    v(instance, attrib, new_value)

    return new_value


def convert(instance, attrib, new_value):
    """
    Run *attrib*'s converter -- if it has one --  on *new_value* and return the
    result.

    .. versionadded:: 20.1.0
    """
    c = attrib.converter
    if c:
        return c(new_value)

    return new_value


# Sentinel for disabling class-wide *on_setattr* hooks for certain attributes.
# autodata stopped working, so the docstring is inlined in the API docs.
NO_OP = object()