def _merge_params_and_taskinputs(cls, params, taskinputs):
"""
params: arguments passed as a dictionary to constructor
As a special case, if a task has only one input, it does not need
to be wrapped in a dict (i.e. `params` can be the value itself).
taskinputs: arguments passed directly as keywords to constructor
This function does the following:
+ Merge dictionary and keyword arguments. Keyword arguments take
precedence.
+ Check that all arguments required by task `run()` signature are
provided.
+ Retrieve any missing argument values from the defaults in `run()`
signature.
+ Cast every input to its expected type. If an input defines multiple
allowable types, the left-most one takes precedence.
"""
if params is None:
params = {}
elif isinstance(params, str):
params = build_parameters(params)
elif isinstance(params, dict):
params = ParameterSet(params)
else:
if len(cls.inputs) == 1:
# For tasks with only one input, don't require dict
θname, θtype = next(iter(cls.inputs.items()))
if len(taskinputs) > 0:
raise TypeError(f"Argument given by name {θname} "
"and position.")
# if not isinstance(taskinputs, θtype):
# # Cast to correct type
# taskinputs = cast(taskinputs, θtype)
taskinputs = ParameterSet({θname: taskinputs})
else:
raise ValueError("`params` should be either a dictionary "
"or a path to a parameter file, however it "
"is of type {}.".format(type(params)))
taskinputs = {**params, **taskinputs}
sigparams = inspect.signature(cls._run).parameters
required_inputs = [
p.name for p in sigparams.values() if p.default is inspect._empty
]
default_inputs = {
p.name: p.default
for p in sigparams.values() if p.default is not inspect._empty
}
if type(cls.__dict__['_run']) is not staticmethod:
# instance and class methods already provide 'self' or 'cls'
firstarg = required_inputs.pop(0)
# Only allowing 'self' and 'cls' ensures we don't accidentally
# remove true input arguments
assert firstarg in ("self", "cls")
if not all((p in taskinputs) for p in required_inputs):
raise TypeError("Missing required inputs '{}'.".format(
set(required_inputs).difference(taskinputs)))
# Add default inputs so they are recorded as task arguments
taskinputs = {**default_inputs, **taskinputs}
# Finally, cast all task inputs
for name, θ in taskinputs.items():
θtype = cls.inputs[name]
if isinstance(θ, LazyCastTypes):
# Can't cast e.g. tasks: they haven't been executed yet
continue
elif not isinstance(θ, θtype):
taskinputs[name] = cast(θ, θtype, 'input')
return taskinputs
