# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
"""The variant module contains data structures that are needed to manage
variants both in packages and in specs.
"""
import collections.abc
import functools
import inspect
import io
import itertools
import re
import llnl.util.lang as lang
import llnl.util.tty.color
from llnl.string import comma_or
import spack.directives
import spack.error as error
import spack.parser
special_variant_values = [None, "none", "*"]
[docs]
class Variant:
"""Represents a variant in a package, as declared in the
variant directive.
"""
def __init__(
self,
name,
default,
description,
values=(True, False),
multi=False,
validator=None,
sticky=False,
):
"""Initialize a package variant.
Args:
name (str): name of the variant
default (str): default value for the variant in case
nothing has been specified
description (str): purpose of the variant
values (sequence): sequence of allowed values or a callable
accepting a single value as argument and returning True if the
value is good, False otherwise
multi (bool): whether multiple CSV are allowed
validator (callable): optional callable used to enforce
additional logic on the set of values being validated
sticky (bool): if true the variant is set to the default value at
concretization time
"""
self.name = name
self.default = default
self.description = str(description)
self.values = None
if values == "*":
# wildcard is a special case to make it easy to say any value is ok
self.single_value_validator = lambda x: True
elif isinstance(values, type):
# supplying a type means any value *of that type*
def isa_type(v):
try:
values(v)
return True
except ValueError:
return False
self.single_value_validator = isa_type
elif callable(values):
# If 'values' is a callable, assume it is a single value
# validator and reset the values to be explicit during debug
self.single_value_validator = values
else:
# Otherwise, assume values is the set of allowed explicit values
self.values = _flatten(values)
self.single_value_validator = lambda x: x in tuple(self.values)
self.multi = multi
self.group_validator = validator
self.sticky = sticky
[docs]
def validate_or_raise(self, vspec, pkg_cls=None):
"""Validate a variant spec against this package variant. Raises an
exception if any error is found.
Args:
vspec (Variant): instance to be validated
pkg_cls (spack.package_base.PackageBase): the package class
that required the validation, if available
Raises:
InconsistentValidationError: if ``vspec.name != self.name``
MultipleValuesInExclusiveVariantError: if ``vspec`` has
multiple values but ``self.multi == False``
InvalidVariantValueError: if ``vspec.value`` contains
invalid values
"""
# Check the name of the variant
if self.name != vspec.name:
raise InconsistentValidationError(vspec, self)
# Check the values of the variant spec
value = vspec.value
if isinstance(vspec.value, (bool, str)):
value = (vspec.value,)
# If the value is exclusive there must be at most one
if not self.multi and len(value) != 1:
raise MultipleValuesInExclusiveVariantError(vspec, pkg_cls)
# Check and record the values that are not allowed
not_allowed_values = [
x for x in value if x != "*" and self.single_value_validator(x) is False
]
if not_allowed_values:
raise InvalidVariantValueError(self, not_allowed_values, pkg_cls)
# Validate the group of values if needed
if self.group_validator is not None and value != ("*",):
self.group_validator(pkg_cls.name, self.name, value)
@property
def allowed_values(self):
"""Returns a string representation of the allowed values for
printing purposes
Returns:
str: representation of the allowed values
"""
# Join an explicit set of allowed values
if self.values is not None:
v = tuple(str(x) for x in self.values)
return ", ".join(v)
# In case we were given a single-value validator
# print the docstring
docstring = inspect.getdoc(self.single_value_validator)
v = docstring if docstring else ""
return v
[docs]
def make_default(self):
"""Factory that creates a variant holding the default value.
Returns:
MultiValuedVariant or SingleValuedVariant or BoolValuedVariant:
instance of the proper variant
"""
return self.make_variant(self.default)
[docs]
def make_variant(self, value):
"""Factory that creates a variant holding the value passed as
a parameter.
Args:
value: value that will be hold by the variant
Returns:
MultiValuedVariant or SingleValuedVariant or BoolValuedVariant:
instance of the proper variant
"""
return self.variant_cls(self.name, value)
@property
def variant_cls(self):
"""Proper variant class to be used for this configuration."""
if self.multi:
return MultiValuedVariant
elif self.values == (True, False):
return BoolValuedVariant
return SingleValuedVariant
def __eq__(self, other):
return (
self.name == other.name
and self.default == other.default
and self.values == other.values
and self.multi == other.multi
and self.single_value_validator == other.single_value_validator
and self.group_validator == other.group_validator
)
def __ne__(self, other):
return not self == other
[docs]
def implicit_variant_conversion(method):
"""Converts other to type(self) and calls method(self, other)
Args:
method: any predicate method that takes another variant as an argument
Returns: decorated method
"""
@functools.wraps(method)
def convert(self, other):
# We don't care if types are different as long as I can convert other to type(self)
try:
other = type(self)(other.name, other._original_value)
except (error.SpecError, ValueError):
return False
return method(self, other)
return convert
def _flatten(values):
"""Flatten instances of _ConditionalVariantValues for internal representation"""
if isinstance(values, DisjointSetsOfValues):
return values
flattened = []
for item in values:
if isinstance(item, _ConditionalVariantValues):
flattened.extend(item)
else:
flattened.append(item)
# There are parts of the variant checking mechanism that expect to find tuples
# here, so it is important to convert the type once we flattened the values.
return tuple(flattened)
[docs]
@lang.lazy_lexicographic_ordering
class AbstractVariant:
"""A variant that has not yet decided who it wants to be. It behaves like
a multi valued variant which **could** do things.
This kind of variant is generated during parsing of expressions like
``foo=bar`` and differs from multi valued variants because it will
satisfy any other variant with the same name. This is because it **could**
do it if it grows up to be a multi valued variant with the right set of
values.
"""
def __init__(self, name, value, propagate=False):
self.name = name
self.propagate = propagate
# Stores 'value' after a bit of massaging
# done by the property setter
self._value = None
self._original_value = None
# Invokes property setter
self.value = value
[docs]
@staticmethod
def from_node_dict(name, value):
"""Reconstruct a variant from a node dict."""
if isinstance(value, list):
# read multi-value variants in and be faithful to the YAML
mvar = MultiValuedVariant(name, ())
mvar._value = tuple(value)
mvar._original_value = mvar._value
return mvar
elif str(value).upper() == "TRUE" or str(value).upper() == "FALSE":
return BoolValuedVariant(name, value)
return SingleValuedVariant(name, value)
[docs]
def yaml_entry(self):
"""Returns a key, value tuple suitable to be an entry in a yaml dict.
Returns:
tuple: (name, value_representation)
"""
return self.name, list(self.value)
@property
def value(self):
"""Returns a tuple of strings containing the values stored in
the variant.
Returns:
tuple: values stored in the variant
"""
return self._value
@value.setter
def value(self, value):
self._value_setter(value)
def _value_setter(self, value):
# Store the original value
self._original_value = value
if not isinstance(value, (tuple, list)):
# Store a tuple of CSV string representations
# Tuple is necessary here instead of list because the
# values need to be hashed
value = re.split(r"\s*,\s*", str(value))
for val in special_variant_values:
if val in value and len(value) > 1:
msg = "'%s' cannot be combined with other variant" % val
msg += " values."
raise InvalidVariantValueCombinationError(msg)
# With multi-value variants it is necessary
# to remove duplicates and give an order
# to a set
self._value = tuple(sorted(set(value)))
def _cmp_iter(self):
yield self.name
value = self._value
if not isinstance(value, tuple):
value = (value,)
value = tuple(str(x) for x in value)
yield value
[docs]
def copy(self):
"""Returns an instance of a variant equivalent to self
Returns:
AbstractVariant: a copy of self
>>> a = MultiValuedVariant('foo', True)
>>> b = a.copy()
>>> assert a == b
>>> assert a is not b
"""
return type(self)(self.name, self._original_value, self.propagate)
[docs]
@implicit_variant_conversion
def satisfies(self, other):
"""Returns true if ``other.name == self.name``, because any value that
other holds and is not in self yet **could** be added.
Args:
other: constraint to be met for the method to return True
Returns:
bool: True or False
"""
# If names are different then `self` does not satisfy `other`
# (`foo=bar` will never satisfy `baz=bar`)
return other.name == self.name
[docs]
def intersects(self, other):
"""Returns True if there are variant matching both self and other, False otherwise."""
if isinstance(other, (SingleValuedVariant, BoolValuedVariant)):
return other.intersects(self)
return other.name == self.name
[docs]
def compatible(self, other):
"""Returns True if self and other are compatible, False otherwise.
As there is no semantic check, two VariantSpec are compatible if
either they contain the same value or they are both multi-valued.
Args:
other: instance against which we test compatibility
Returns:
bool: True or False
"""
# If names are different then `self` is not compatible with `other`
# (`foo=bar` is incompatible with `baz=bar`)
return self.intersects(other)
[docs]
@implicit_variant_conversion
def constrain(self, other):
"""Modify self to match all the constraints for other if both
instances are multi-valued. Returns True if self changed,
False otherwise.
Args:
other: instance against which we constrain self
Returns:
bool: True or False
"""
if self.name != other.name:
raise ValueError("variants must have the same name")
old_value = self.value
values = list(sorted(set(self.value + other.value)))
# If we constraint wildcard by another value, just take value
if "*" in values and len(values) > 1:
values.remove("*")
self.value = ",".join(values)
return old_value != self.value
def __contains__(self, item):
return item in self._value
def __repr__(self):
return f"{type(self).__name__}({repr(self.name)}, {repr(self._original_value)})"
def __str__(self):
delim = "==" if self.propagate else "="
values = spack.parser.quote_if_needed(",".join(str(v) for v in self.value))
return f"{self.name}{delim}{values}"
[docs]
class MultiValuedVariant(AbstractVariant):
"""A variant that can hold multiple values at once."""
[docs]
@implicit_variant_conversion
def satisfies(self, other):
"""Returns true if ``other.name == self.name`` and ``other.value`` is
a strict subset of self. Does not try to validate.
Args:
other: constraint to be met for the method to return True
Returns:
bool: True or False
"""
super_sat = super().satisfies(other)
if not super_sat:
return False
if "*" in other or "*" in self:
return True
# allow prefix find on patches
if self.name == "patches":
return all(any(w.startswith(v) for w in self.value) for v in other.value)
# Otherwise we want all the values in `other` to be also in `self`
return all(v in self.value for v in other.value)
[docs]
def append(self, value):
"""Add another value to this multi-valued variant."""
self._value = tuple(sorted((value,) + self._value))
self._original_value = ",".join(self._value)
def __str__(self):
# Special-case patches to not print the full 64 character sha256
if self.name == "patches":
values_str = ",".join(x[:7] for x in self.value)
else:
values_str = ",".join(str(x) for x in self.value)
delim = "==" if self.propagate else "="
return f"{self.name}{delim}{spack.parser.quote_if_needed(values_str)}"
[docs]
class SingleValuedVariant(AbstractVariant):
"""A variant that can hold multiple values, but one at a time."""
def _value_setter(self, value):
# Treat the value as a multi-valued variant
super()._value_setter(value)
# Then check if there's only a single value
if len(self._value) != 1:
raise MultipleValuesInExclusiveVariantError(self, None)
self._value = str(self._value[0])
def __str__(self):
delim = "==" if self.propagate else "="
return f"{self.name}{delim}{spack.parser.quote_if_needed(self.value)}"
[docs]
@implicit_variant_conversion
def satisfies(self, other):
abstract_sat = super().satisfies(other)
return abstract_sat and (
self.value == other.value or other.value == "*" or self.value == "*"
)
[docs]
def intersects(self, other):
return self.satisfies(other)
[docs]
def compatible(self, other):
return self.satisfies(other)
[docs]
@implicit_variant_conversion
def constrain(self, other):
if self.name != other.name:
raise ValueError("variants must have the same name")
if other.value == "*":
return False
if self.value == "*":
self.value = other.value
return True
if self.value != other.value:
raise UnsatisfiableVariantSpecError(other.value, self.value)
return False
def __contains__(self, item):
return item == self.value
[docs]
def yaml_entry(self):
return self.name, self.value
[docs]
class BoolValuedVariant(SingleValuedVariant):
"""A variant that can hold either True or False.
BoolValuedVariant can also hold the value '*', for coerced
comparisons between ``foo=*`` and ``+foo`` or ``~foo``."""
def _value_setter(self, value):
# Check the string representation of the value and turn
# it to a boolean
if str(value).upper() == "TRUE":
self._original_value = value
self._value = True
elif str(value).upper() == "FALSE":
self._original_value = value
self._value = False
elif str(value) == "*":
self._original_value = value
self._value = "*"
else:
msg = 'cannot construct a BoolValuedVariant for "{0}" from '
msg += "a value that does not represent a bool"
raise ValueError(msg.format(self.name))
def __contains__(self, item):
return item is self.value
def __str__(self):
if self.propagate:
return "{0}{1}".format("++" if self.value else "~~", self.name)
return "{0}{1}".format("+" if self.value else "~", self.name)
[docs]
class VariantMap(lang.HashableMap):
"""Map containing variant instances. New values can be added only
if the key is not already present.
"""
def __init__(self, spec):
super().__init__()
self.spec = spec
def __setitem__(self, name, vspec):
# Raise a TypeError if vspec is not of the right type
if not isinstance(vspec, AbstractVariant):
msg = "VariantMap accepts only values of variant types"
msg += " [got {0} instead]".format(type(vspec).__name__)
raise TypeError(msg)
# Raise an error if the variant was already in this map
if name in self.dict:
msg = 'Cannot specify variant "{0}" twice'.format(name)
raise DuplicateVariantError(msg)
# Raise an error if name and vspec.name don't match
if name != vspec.name:
msg = 'Inconsistent key "{0}", must be "{1}" to match VariantSpec'
raise KeyError(msg.format(name, vspec.name))
# Set the item
super().__setitem__(name, vspec)
[docs]
def substitute(self, vspec):
"""Substitutes the entry under ``vspec.name`` with ``vspec``.
Args:
vspec: variant spec to be substituted
"""
if vspec.name not in self:
msg = "cannot substitute a key that does not exist [{0}]"
raise KeyError(msg.format(vspec.name))
# Set the item
super().__setitem__(vspec.name, vspec)
[docs]
def satisfies(self, other):
return all(k in self and self[k].satisfies(other[k]) for k in other)
[docs]
def intersects(self, other):
return all(self[k].intersects(other[k]) for k in other if k in self)
[docs]
def constrain(self, other):
"""Add all variants in other that aren't in self to self. Also
constrain all multi-valued variants that are already present.
Return True if self changed, False otherwise
Args:
other (VariantMap): instance against which we constrain self
Returns:
bool: True or False
"""
if other.spec is not None and other.spec._concrete:
for k in self:
if k not in other:
raise UnsatisfiableVariantSpecError(self[k], "<absent>")
changed = False
for k in other:
if k in self:
# If they are not compatible raise an error
if not self[k].compatible(other[k]):
raise UnsatisfiableVariantSpecError(self[k], other[k])
# If they are compatible merge them
changed |= self[k].constrain(other[k])
else:
# If it is not present copy it straight away
self[k] = other[k].copy()
changed = True
return changed
@property
def concrete(self):
"""Returns True if the spec is concrete in terms of variants.
Returns:
bool: True or False
"""
return self.spec._concrete or all(v in self for v in self.spec.package_class.variants)
[docs]
def copy(self):
"""Return an instance of VariantMap equivalent to self.
Returns:
VariantMap: a copy of self
"""
clone = VariantMap(self.spec)
for name, variant in self.items():
clone[name] = variant.copy()
return clone
def __str__(self):
if not self:
return ""
# print keys in order
sorted_keys = sorted(self.keys())
# Separate boolean variants from key-value pairs as they print
# differently. All booleans go first to avoid ' ~foo' strings that
# break spec reuse in zsh.
bool_keys = []
kv_keys = []
for key in sorted_keys:
bool_keys.append(key) if isinstance(self[key].value, bool) else kv_keys.append(key)
# add spaces before and after key/value variants.
string = io.StringIO()
for key in bool_keys:
string.write(str(self[key]))
for key in kv_keys:
string.write(" ")
string.write(str(self[key]))
return string.getvalue()
[docs]
def substitute_abstract_variants(spec):
"""Uses the information in `spec.package` to turn any variant that needs
it into a SingleValuedVariant.
This method is best effort. All variants that can be substituted will be
substituted before any error is raised.
Args:
spec: spec on which to operate the substitution
"""
# This method needs to be best effort so that it works in matrix exlusion
# in $spack/lib/spack/spack/spec_list.py
failed = []
for name, v in spec.variants.items():
if name in spack.directives.reserved_names:
if name == "dev_path":
new_variant = SingleValuedVariant(name, v._original_value)
spec.variants.substitute(new_variant)
continue
if name not in spec.package_class.variants:
failed.append(name)
continue
pkg_variant, _ = spec.package_class.variants[name]
new_variant = pkg_variant.make_variant(v._original_value)
pkg_variant.validate_or_raise(new_variant, spec.package_class)
spec.variants.substitute(new_variant)
# Raise all errors at once
if failed:
raise UnknownVariantError(spec, failed)
# The class below inherit from Sequence to disguise as a tuple and comply
# with the semantic expected by the 'values' argument of the variant directive
[docs]
class DisjointSetsOfValues(collections.abc.Sequence):
"""Allows combinations from one of many mutually exclusive sets.
The value ``('none',)`` is reserved to denote the empty set
and therefore no other set can contain the item ``'none'``.
Args:
*sets (list): mutually exclusive sets of values
"""
_empty_set = set(("none",))
def __init__(self, *sets):
self.sets = [set(_flatten(x)) for x in sets]
# 'none' is a special value and can appear only in a set of
# a single element
if any("none" in s and s != set(("none",)) for s in self.sets):
raise error.SpecError(
"The value 'none' represents the empty set,"
" and must appear alone in a set. Use the "
"method 'allow_empty_set' to add it."
)
# Sets should not intersect with each other
if any(s1 & s2 for s1, s2 in itertools.combinations(self.sets, 2)):
raise error.SpecError("sets in input must be disjoint")
#: Attribute used to track values which correspond to
#: features which can be enabled or disabled as understood by the
#: package's build system.
self.feature_values = tuple(itertools.chain.from_iterable(self.sets))
self.default = None
self.multi = True
self.error_fmt = (
"this variant accepts combinations of values from "
"exactly one of the following sets '{values}' "
"@*r{{[{package}, variant '{variant}']}}"
)
[docs]
def with_default(self, default):
"""Sets the default value and returns self."""
self.default = default
return self
[docs]
def with_error(self, error_fmt):
"""Sets the error message format and returns self."""
self.error_fmt = error_fmt
return self
[docs]
def with_non_feature_values(self, *values):
"""Marks a few values as not being tied to a feature."""
self.feature_values = tuple(x for x in self.feature_values if x not in values)
return self
[docs]
def allow_empty_set(self):
"""Adds the empty set to the current list of disjoint sets."""
if self._empty_set in self.sets:
return self
# Create a new object to be returned
object_with_empty_set = type(self)(("none",), *self.sets)
object_with_empty_set.error_fmt = self.error_fmt
object_with_empty_set.feature_values = self.feature_values + ("none",)
return object_with_empty_set
[docs]
def prohibit_empty_set(self):
"""Removes the empty set from the current list of disjoint sets."""
if self._empty_set not in self.sets:
return self
# Create a new object to be returned
sets = [s for s in self.sets if s != self._empty_set]
object_without_empty_set = type(self)(*sets)
object_without_empty_set.error_fmt = self.error_fmt
object_without_empty_set.feature_values = tuple(
x for x in self.feature_values if x != "none"
)
return object_without_empty_set
def __getitem__(self, idx):
return tuple(itertools.chain.from_iterable(self.sets))[idx]
def __len__(self):
return len(itertools.chain.from_iterable(self.sets))
@property
def validator(self):
def _disjoint_set_validator(pkg_name, variant_name, values):
# If for any of the sets, all the values are in it return True
if any(all(x in s for x in values) for s in self.sets):
return
format_args = {"variant": variant_name, "package": pkg_name, "values": values}
msg = self.error_fmt + " @*r{{[{package}, variant '{variant}']}}"
msg = llnl.util.tty.color.colorize(msg.format(**format_args))
raise error.SpecError(msg)
return _disjoint_set_validator
def _a_single_value_or_a_combination(single_value, *values):
error = "the value '" + single_value + "' is mutually exclusive with any of the other values"
return (
DisjointSetsOfValues((single_value,), values)
.with_default(single_value)
.with_error(error)
.with_non_feature_values(single_value)
)
# TODO: The factories below are used by package writers to set values of
# TODO: multi-valued variants. It could be worthwhile to gather them in
# TODO: a common namespace (like 'multi') in the future.
[docs]
def any_combination_of(*values):
"""Multi-valued variant that allows any combination of the specified
values, and also allows the user to specify 'none' (as a string) to choose
none of them.
It is up to the package implementation to handle the value 'none'
specially, if at all.
Args:
*values: allowed variant values
Returns:
a properly initialized instance of DisjointSetsOfValues
"""
return _a_single_value_or_a_combination("none", *values)
[docs]
def auto_or_any_combination_of(*values):
"""Multi-valued variant that allows any combination of a set of values
(but not the empty set) or 'auto'.
Args:
*values: allowed variant values
Returns:
a properly initialized instance of DisjointSetsOfValues
"""
return _a_single_value_or_a_combination("auto", *values)
#: Multi-valued variant that allows any combination picking
#: from one of multiple disjoint sets
[docs]
def disjoint_sets(*sets):
"""Multi-valued variant that allows any combination picking from one
of multiple disjoint sets of values, and also allows the user to specify
'none' (as a string) to choose none of them.
It is up to the package implementation to handle the value 'none'
specially, if at all.
Args:
*sets:
Returns:
a properly initialized instance of DisjointSetsOfValues
"""
return DisjointSetsOfValues(*sets).allow_empty_set().with_default("none")
[docs]
@functools.total_ordering
class Value:
"""Conditional value that might be used in variants."""
def __init__(self, value, when):
self.value = value
self.when = when
def __repr__(self):
return "Value({0.value}, when={0.when})".format(self)
def __str__(self):
return str(self.value)
def __hash__(self):
# Needed to allow testing the presence of a variant in a set by its value
return hash(self.value)
def __eq__(self, other):
if isinstance(other, (str, bool)):
return self.value == other
return self.value == other.value
def __lt__(self, other):
if isinstance(other, str):
return self.value < other
return self.value < other.value
class _ConditionalVariantValues(lang.TypedMutableSequence):
"""A list, just with a different type"""
[docs]
def conditional(*values, **kwargs):
"""Conditional values that can be used in variant declarations."""
if len(kwargs) != 1 and "when" not in kwargs:
raise ValueError('conditional statement expects a "when=" parameter only')
when = kwargs["when"]
return _ConditionalVariantValues([Value(x, when=when) for x in values])
[docs]
class DuplicateVariantError(error.SpecError):
"""Raised when the same variant occurs in a spec twice."""
[docs]
class UnknownVariantError(error.SpecError):
"""Raised when an unknown variant occurs in a spec."""
def __init__(self, spec, variants):
self.unknown_variants = variants
variant_str = "variant" if len(variants) == 1 else "variants"
msg = (
'trying to set {0} "{1}" in package "{2}", but the package'
" has no such {0} [happened when validating '{3}']"
)
msg = msg.format(variant_str, comma_or(variants), spec.name, spec.root)
super().__init__(msg)
[docs]
class InconsistentValidationError(error.SpecError):
"""Raised if the wrong validator is used to validate a variant."""
def __init__(self, vspec, variant):
msg = 'trying to validate variant "{0.name}" ' 'with the validator of "{1.name}"'
super().__init__(msg.format(vspec, variant))
[docs]
class MultipleValuesInExclusiveVariantError(error.SpecError, ValueError):
"""Raised when multiple values are present in a variant that wants
only one.
"""
def __init__(self, variant, pkg):
msg = 'multiple values are not allowed for variant "{0.name}"{1}'
pkg_info = ""
if pkg is not None:
pkg_info = ' in package "{0}"'.format(pkg.name)
super().__init__(msg.format(variant, pkg_info))
[docs]
class InvalidVariantValueCombinationError(error.SpecError):
"""Raised when a variant has values '*' or 'none' with other values."""
[docs]
class InvalidVariantValueError(error.SpecError):
"""Raised when a valid variant has at least an invalid value."""
def __init__(self, variant, invalid_values, pkg):
msg = 'invalid values for variant "{0.name}"{2}: {1}\n'
pkg_info = ""
if pkg is not None:
pkg_info = ' in package "{0}"'.format(pkg.name)
super().__init__(msg.format(variant, invalid_values, pkg_info))
[docs]
class InvalidVariantForSpecError(error.SpecError):
"""Raised when an invalid conditional variant is specified."""
def __init__(self, variant, when, spec):
msg = "Invalid variant {0} for spec {1}.\n"
msg += "{0} is only available for {1.name} when satisfying one of {2}."
super().__init__(msg.format(variant, spec, when))
[docs]
class UnsatisfiableVariantSpecError(error.UnsatisfiableSpecError):
"""Raised when a spec variant conflicts with package constraints."""
def __init__(self, provided, required):
super().__init__(provided, required, "variant")