199 lines
6.3 KiB
Python
199 lines
6.3 KiB
Python
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# -*- encoding: utf-8 -*-
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# merge_args v0.1.5
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# Merge signatures of two functions with Advanced Hackery.
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# Copyright © 2018-2023, Chris Warrick.
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions, and the following disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions, and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# 3. Neither the name of the author of this software nor the names of
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# contributors to this software may be used to endorse or promote
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# products derived from this software without specific prior written
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# consent.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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"""
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Merge signatures of two functions with Advanced Hackery. Useful for wrappers.
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Usage: @merge_args(old_function)
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"""
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import inspect
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import itertools
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import types
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import functools
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import sys
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import typing
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__version__ = '0.1.5'
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__all__ = ('merge_args',)
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PY38 = sys.version_info >= (3, 8)
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PY310 = sys.version_info >= (3, 10)
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PY311 = sys.version_info >= (3, 11)
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def _blank(): # pragma: no cover
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pass
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def _merge(
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source,
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dest,
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drop_args: typing.Optional[typing.List[str]] = None,
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drop_kwonlyargs: typing.Optional[typing.List[str]] = None,
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):
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"""Merge the signatures of ``source`` and ``dest``.
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``dest`` args go before ``source`` args in all three categories
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(positional, keyword-maybe, keyword-only).
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"""
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if drop_args is None:
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drop_args = []
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if drop_kwonlyargs is None:
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drop_kwonlyargs = []
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source_spec = inspect.getfullargspec(source)
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dest_spec = inspect.getfullargspec(dest)
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if source_spec.varargs or source_spec.varkw:
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return dest
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source_all = source_spec.args
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dest_all = dest_spec.args
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if source_spec.defaults:
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source_pos = source_all[:-len(source_spec.defaults)]
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source_kw = source_all[-len(source_spec.defaults):]
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else:
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source_pos = source_all
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source_kw = []
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if dest_spec.defaults:
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dest_pos = dest_all[:-len(dest_spec.defaults)]
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dest_kw = dest_all[-len(dest_spec.defaults):]
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else:
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dest_pos = dest_all
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dest_kw = []
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args_merged = dest_pos
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for a in source_pos:
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if a not in args_merged and a not in drop_args:
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args_merged.append(a)
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defaults_merged = []
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for a, default in itertools.chain(
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zip(dest_kw, dest_spec.defaults or []),
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zip(source_kw, source_spec.defaults or [])
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):
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if a not in args_merged and a not in drop_args:
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args_merged.append(a)
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defaults_merged.append(default)
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kwonlyargs_merged = dest_spec.kwonlyargs
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for a in source_spec.kwonlyargs:
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if a not in kwonlyargs_merged and a not in drop_kwonlyargs:
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kwonlyargs_merged.append(a)
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args_all = tuple(args_merged + kwonlyargs_merged)
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if PY38:
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replace_kwargs = {
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'co_argcount': len(args_merged),
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'co_kwonlyargcount': len(kwonlyargs_merged),
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'co_posonlyargcount': dest.__code__.co_posonlyargcount,
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'co_nlocals': len(args_all),
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'co_flags': source.__code__.co_flags,
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'co_varnames': args_all,
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'co_filename': dest.__code__.co_filename,
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'co_name': dest.__code__.co_name,
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'co_firstlineno': dest.__code__.co_firstlineno,
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}
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if PY310:
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replace_kwargs['co_linetable'] = dest.__code__.co_linetable
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else:
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replace_kwargs['co_lnotab'] = dest.__code__.co_lnotab
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if PY311:
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replace_kwargs['co_exceptiontable'] = dest.__code__.co_exceptiontable
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replace_kwargs['co_qualname'] = dest.__code__.co_qualname
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passer_code = _blank.__code__.replace(**replace_kwargs)
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else:
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passer_args = [
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len(args_merged),
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len(kwonlyargs_merged),
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_blank.__code__.co_nlocals,
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_blank.__code__.co_stacksize,
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source.__code__.co_flags,
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_blank.__code__.co_code, (), (),
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args_all, dest.__code__.co_filename,
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dest.__code__.co_name,
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dest.__code__.co_firstlineno,
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dest.__code__.co_lnotab,
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]
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passer_code = types.CodeType(*passer_args)
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passer = types.FunctionType(passer_code, globals())
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dest.__wrapped__ = passer
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# annotations
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# ensure we take destination’s return annotation
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has_dest_ret = 'return' in dest.__annotations__
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if has_dest_ret:
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dest_ret = dest.__annotations__['return']
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for v in ('__kwdefaults__', '__annotations__'):
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out = getattr(source, v)
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if out is None:
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out = {}
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if getattr(dest, v) is not None:
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out = out.copy()
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out.update(getattr(dest, v))
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setattr(passer, v, out)
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if has_dest_ret:
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passer.__annotations__['return'] = dest_ret
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dest.__annotations__ = passer.__annotations__
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passer.__defaults__ = tuple(defaults_merged)
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if not dest.__doc__:
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dest.__doc__ = source.__doc__
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return dest
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def merge_args(
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source,
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drop_args: typing.Optional[typing.List[str]] = None,
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drop_kwonlyargs: typing.Optional[typing.List[str]] = None,
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):
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"""Merge the signatures of two functions."""
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try:
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return functools.partial(
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lambda x, y: _merge(x, y, drop_args, drop_kwonlyargs), source
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)
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except TypeError:
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pass
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