Source code for reframe.utility.typecheck

# Copyright 2016-2023 Swiss National Supercomputing Centre (CSCS/ETH Zurich)
# ReFrame Project Developers. See the top-level LICENSE file for details.
# SPDX-License-Identifier: BSD-3-Clause

'''Dynamic recursive type checking of collections.

This module defines types for collections, such as lists, dictionaries etc.,
that you can use with the :py:func:`isinstance` builtin function to
recursively type check all the elements of the collection. Suppose you have a
list of integers, suchs as ``[1, 2, 3]``, the following checks should be true:

.. code-block:: python

    l = [1, 2, 3]
    assert isinstance(l, List[int]) == True
    assert isinstance(l, List[float]) == False

Aggregate types can be combined in an arbitrary depth, so that you can type
check any complex data strcture:

.. code-block:: python

    d = {'a': [1, 2], 'b': [3, 4]}
    assert isisntance(d, Dict) == True
    assert isisntance(d, Dict[str, List[int]]) == True

This module offers the following aggregate types:

.. py:data:: List[T]

   A list with elements of type :class:`T`.

.. py:data:: Set[T]

   A set with elements of type :class:`T`.

.. py:data:: Dict[K,V]

   A dictionary with keys of type :class:`K` and values of type :class:`V`.

.. py:data:: Tuple[T]

   A tuple with elements of type :class:`T`.

.. py:data:: Tuple[T1,T2,...,Tn]

   A tuple with ``n`` elements, whose types are exactly :class:`T1`,
   :class:`T2`, ..., :class:`Tn` in that order.

.. py:data:: Str[patt]

   A string type whose members are all the strings matching the regular
   expression ``patt``.

Implementation details

Internally, this module leverages metaclasses and the
:py:func:`__isinstancecheck__` method to customize the behaviour of the
:py:func:`isinstance` builtin.

By implementing also the :py:func:`__getitem__` accessor method, this module
follows the look-and-feel of the type hints proposed in `PEP484
<>`__. This method returns a new type
that is a subtype of the base container type. Using the facilities of
:py:class:`abc.ABCMeta`, builtin types, such as :py:class:`list`,
:py:class:`str` etc. are registered as subtypes of the base container types
offered by this module. The type hierarchy of the types defined in this module
is the following (example shown for :class:`List`, but it is analogous for
the rest of the types):

.. code-block:: none

        /   |
       /    |
      /     |
    list  List[T]

In the above example :class:`T` may refer to any type, so that
:class:`List[List[int]]` is an instance of :class:`List`, but not an instance
of :class:`List[int]`.


import abc
import datetime
import re

[docs]class ConvertibleType(abc.ABCMeta): '''A type that support conversions from other types. This is a metaclass that allows classes that use it to support arbitrary conversions from other types using a cast-like syntax without having to change their constructor: .. code-block:: python new_obj = convertible_type(another_type) For example, a class whose constructor accepts and :class:`int` may need to support a cast-from-string conversion. This is particular useful if you want a custom-typed test :attr:`~reframe.core.pipeline.RegressionMixin.variable` to be able to be set from the command line using the :option:`-S` option. In order to support such conversions, a class must use this metaclass and define a class method, named as :obj:`__rfm_cast_<type>__`, for each of the type conversion that needs to support . The following is an example of a class :class:`X` that its normal constructor accepts two arguments but it also allows conversions from string: .. code-block:: python class X(metaclass=ConvertibleType): def __init__(self, x, y): = (x, y) @classmethod def __rfm_cast_str__(cls, s): return X(*(int(x) for x in s.split(',', maxsplit=1))) assert X(2, 3).data == X('2,3').data .. versionadded:: 3.8.0 ''' def __call__(cls, *args, **kwargs): if len(args) == 1: cast_fn_name = f'__rfm_cast_{type(args[0]).__name__}__' if hasattr(cls, cast_fn_name): cast_fn = getattr(cls, cast_fn_name) return cast_fn(args[0]) return super().__call__(*args, **kwargs)
# Metaclasses that implement the isinstance logic for the different builtin # container types class _BuiltinType(ConvertibleType): def __init__(cls, name, bases, namespace): # Make sure that the class defines `_type` cls._bases = bases cls._namespace = namespace assert hasattr(cls, '_type') cls.register(cls._type) def __instancecheck__(cls, inst): if hasattr(cls, '_types'): return any(issubclass(type(inst), t) for t in cls._types) if hasattr(cls, '_xtype'): return not issubclass(type(inst), cls._xtype) return issubclass(type(inst), cls) def __or__(cls, other): new_type = _BuiltinType(f'{cls.__name__}|{other.__name__}', cls._bases, cls._namespace) new_type._types = (cls, other) return new_type def __invert__(cls): new_type = _BuiltinType(f'~{cls.__name__}', cls._bases, cls._namespace) new_type._xtype = cls return new_type class _SequenceType(_BuiltinType): '''A metaclass for containers with uniformly typed elements.''' def __init__(cls, name, bases, namespace): super().__init__(name, bases, namespace) cls._elem_type = None def __instancecheck__(cls, inst): if not super().__instancecheck__(inst): return False if cls._elem_type is None: return True return all(isinstance(c, cls._elem_type) for c in inst) def __getitem__(cls, elem_type): if not isinstance(elem_type, type): raise TypeError('{0} is not a valid type'.format(elem_type)) if isinstance(elem_type, tuple): raise TypeError('invalid type specification for container type: ' 'expected ContainerType[elem_type]') ret = _SequenceType('%s[%s]' % (cls.__name__, elem_type.__name__), cls._bases, cls._namespace) ret._elem_type = elem_type cls.register(ret) return ret def __rfm_cast_str__(cls, s): container_type = cls._type elem_type = cls._elem_type return container_type(elem_type(e) for e in s.split(',')) class _TupleType(_SequenceType): '''A metaclass for tuples. Tuples may contain uniformly-typed elements or non-uniformly typed ones. ''' def __instancecheck__(cls, inst): if not issubclass(type(inst), cls): return False if cls._elem_type is None: return True if len(cls._elem_type) == 1: # tuple with elements of the same type return all(isinstance(c, cls._elem_type[0]) for c in inst) # Non-uniformly typed tuple if len(inst) != len(cls._elem_type): return False return all(isinstance(elem, req_type) for req_type, elem in zip(cls._elem_type, inst)) def __getitem__(cls, elem_types): if not isinstance(elem_types, tuple): elem_types = (elem_types,) for t in elem_types: if not isinstance(t, type): raise TypeError('{0} is not a valid type'.format(t)) cls_name = '%s[%s]' % ( cls.__name__, ','.join(c.__name__ for c in elem_types) ) ret = _TupleType(cls_name, cls._bases, cls._namespace) ret._elem_type = elem_types cls.register(ret) return ret def __rfm_cast_str__(cls, s): container_type = cls._type elem_types = cls._elem_type elems = s.split(',') if len(elem_types) == 1: elem_t = elem_types[0] return container_type(elem_t(e) for e in elems) elif len(elem_types) != len(elems): raise TypeError(f'cannot convert string {s!r} to {cls.__name__!r}') else: return container_type( elem_t(e) for elem_t, e in zip(elem_types, elems) ) class _MappingType(_BuiltinType): '''A metaclass for type checking mapping types.''' def __init__(cls, name, bases, namespace): super().__init__(name, bases, namespace) cls._key_type = None cls._value_type = None cls._bases = bases cls._namespace = namespace def __instancecheck__(cls, inst): if not issubclass(type(inst), cls): return False if cls._key_type is None and cls._key_type is None: return True assert cls._key_type is not None and cls._value_type is not None has_valid_keys = all(isinstance(k, cls._key_type) for k in inst.keys()) has_valid_values = all(isinstance(v, cls._value_type) for v in inst.values()) return has_valid_keys and has_valid_values def __getitem__(cls, typespec): try: key_type, value_type = typespec except ValueError: raise TypeError( 'invalid type specification for mapping type: ' 'expected MappingType[key_type, value_type]') from None for t in typespec: if not isinstance(t, type): raise TypeError('{0} is not a valid type'.format(t)) cls_name = '%s[%s,%s]' % (cls.__name__, key_type.__name__, value_type.__name__) ret = _MappingType(cls_name, cls._bases, cls._namespace) ret._key_type = key_type ret._value_type = value_type cls.register(ret) return ret def __rfm_cast_str__(cls, s): mappping_type = cls._type key_type = cls._key_type value_type = cls._value_type seq = [] for key_datum in s.split(','): try: k, v = key_datum.split(':') except ValueError: # Re-raise as TypeError raise TypeError( f'cannot convert string {s!r} to {cls.__name__!r}' ) from None seq.append((key_type(k), value_type(v))) return mappping_type(seq) class _StrType(_SequenceType): '''A metaclass for type checking string types.''' def __instancecheck__(cls, inst): if not issubclass(type(inst), cls): return False if cls._elem_type is None: return True # _elem_type is a regex return re.fullmatch(cls._elem_type, inst) is not None def __getitem__(cls, patt): if not isinstance(patt, str): raise TypeError('invalid type specification for string type: ' 'expected _StrType[regex]') ret = _StrType("%s[r'%s']" % (cls.__name__, patt), cls._bases, cls._namespace) ret._elem_type = patt cls.register(ret) return ret def __rfm_cast_str__(cls, s): if not isinstance(s, cls): raise TypeError(f'cannot convert string {s!r} to {cls.__name__!r}') return s
[docs]class Bool(metaclass=_BuiltinType): '''A boolean type accepting implicit conversions from strings. This type represents a boolean value but allows implicit conversions from :class:`str`. More specifically, the following conversions are supported: - The strings ``'yes'``, ``'y'``, 'true'`` and ``'1'`` are converted to ``True``. - The strings ``'no'``, ``'n'``, ``'false'`` and ``'0'`` are converted to ``False``. The built-in :class:`bool` type is registered as a subclass of this type. Boolean test variables that are meant to be set properly from the command line must be declared of this type and not :class:`bool`. .. versionchanged:: 4.3.3 The strings ``'y'`` and ``'n'`` are also recognized as valid boolean values and string comparison is now case-insensitive. ''' _type = bool @classmethod def __rfm_cast_str__(cls, s): s = s.lower() if s in ('true', 'yes', 'y', '1'): return True elif s in ('false', 'no', 'n', '0'): return False raise TypeError(f'cannot convert {s!r} to bool')
def make_meta_type(name, cls, metacls=_BuiltinType): namespace = metacls.__prepare__(name, ()) namespace['_type'] = cls ret = metacls(name, (), namespace) return ret Dict = make_meta_type('Dict', dict, _MappingType) Float = make_meta_type('Float', float) Integer = make_meta_type('Integer', int) List = make_meta_type('List', list, _SequenceType) Set = make_meta_type('Set', set, _SequenceType) Str = make_meta_type('Str', str, _StrType) Tuple = make_meta_type('Tuple', tuple, _TupleType)
[docs]class Duration(metaclass=ConvertibleType): '''A float type that represents duration in seconds. This type supports the following implicit conversions: - From integer values - From string values in the form of ``<days>d<hours>h<minutes>m<seconds>s`` .. versionadded:: 4.2 ''' def _assert_non_negative(val): if val < 0: raise ValueError('duration cannot be negative') return val @classmethod def __rfm_cast_int__(cls, val): return Duration._assert_non_negative(float(val)) @classmethod def __rfm_cast_float__(cls, val): return Duration._assert_non_negative(val) @classmethod def __rfm_cast_str__(cls, val): # First try to convert to a float try: val = float(val) except ValueError: time_match = re.match(r'^((?P<days>\d+)d)?' r'((?P<hours>\d+)h)?' r'((?P<minutes>\d+)m)?' r'((?P<seconds>\d+)s)?$', val) if not time_match: raise ValueError(f'invalid duration: {val}') from None val = datetime.timedelta( **{k: int(v) for k, v in time_match.groupdict().items() if v} ).total_seconds() return Duration._assert_non_negative(val)