Support typing.NewType in from_type

[Daenyth]

Using version 3.30.4

In [13]: from typing import NewType, NamedTuple
    ...: MyInt = NewType('MyInt', int)
    ...: class T(NamedTuple):
    ...:     x: MyInt
    ...:     y: str
    ...:

Produces a rather gross stack trace with InvalidArgument: thing=<function NewType.<locals>.new_type at 0x107fd40d0> must be a type

Trace

In [14]: st.from_type(T).example()
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/strategies.py in cached_strategy(*args, **kwargs)
    104         try:
--> 105             return STRATEGY_CACHE[cache_key]
    106         except TypeError:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/cache.py in __getitem__(self, key)
     69     def __getitem__(self, key):
---> 70         i = self.keys_to_indices[key]
     71         result = self.data[i]

KeyError: (<function from_type at 0x106c740d0>, ((<class 'type'>, <class '__main__.T'>),), frozenset())

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/strategies.py in cached_strategy(*args, **kwargs)
    104         try:
--> 105             return STRATEGY_CACHE[cache_key]
    106         except TypeError:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/cache.py in __getitem__(self, key)
     69     def __getitem__(self, key):
---> 70         i = self.keys_to_indices[key]
     71         result = self.data[i]

KeyError: (<function from_type at 0x106c740d0>, ((<class 'function'>, <function NewType.<locals>.new_type at 0x107fd40d0>),), frozenset())

During handling of the above exception, another exception occurred:

InvalidArgument                           Traceback (most recent call last)
<ipython-input-14-87157b77bd3c> in <module>()
----> 1 st.from_type(T).example()

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/strategies.py in example(self, random)
    284                     max_iterations=1000,
    285                     database=None,
--> 286                     verbosity=Verbosity.quiet,
    287                 )
    288             )

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/core.py in find(specifier, condition, settings, random, database_key)
   1067         database_key=database_key,
   1068     )
-> 1069     runner.run()
   1070     note_engine_for_statistics(runner)
   1071     run_time = time.time() - start

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/engine.py in run(self)
    380         with self.settings:
    381             try:
--> 382                 self._run()
    383             except RunIsComplete:
    384                 pass

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/engine.py in _run(self)
    754
    755         self.reuse_existing_examples()
--> 756         self.generate_new_examples()
    757
    758         if (

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/engine.py in generate_new_examples(self)
    655             draw_bytes=lambda data, n: self.__rewrite_for_novelty(
    656                 data, hbytes(n)))
--> 657         self.test_function(zero_data)
    658
    659         count = 0

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/engine.py in test_function(self, data)
    122         self.call_count += 1
    123         try:
--> 124             self._test_function(data)
    125             data.freeze()
    126         except StopTest as e:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/core.py in template_condition(data)
   1036             try:
   1037                 data.is_find = True
-> 1038                 result = data.draw(search)
   1039                 data.note(result)
   1040                 success = condition(result)

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    123             try:
    124                 sys.settrace(None)
--> 125                 return self.__draw(strategy)
    126             finally:
    127                 sys.settrace(original_tracer)

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/lazy.py in do_draw(self, data)
    165
    166     def do_draw(self, data):
--> 167         return data.draw(self.wrapped_strategy)

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    127                 sys.settrace(original_tracer)
    128         else:
--> 129             return self.__draw(strategy)
    130
    131     def __draw(self, strategy):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/strategies.py in do_draw(self, data)
    505             i = data.index
    506             try:
--> 507                 return self.pack(data.draw(self.mapped_strategy))
    508             except UnsatisfiedAssumption:
    509                 if data.index == i:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    127                 sys.settrace(original_tracer)
    128         else:
--> 129             return self.__draw(strategy)
    130
    131     def __draw(self, strategy):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/lazy.py in do_draw(self, data)
    165
    166     def do_draw(self, data):
--> 167         return data.draw(self.wrapped_strategy)

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    127                 sys.settrace(original_tracer)
    128         else:
--> 129             return self.__draw(strategy)
    130
    131     def __draw(self, strategy):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/collections.py in do_draw(self, data)
     58     def do_draw(self, data):
     59         return self.newtuple(
---> 60             data.draw(e) for e in self.element_strategies
     61         )
     62

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/collections.py in newtuple(self, xs)
     54     def newtuple(self, xs):
     55         """Produce a new tuple of the correct type."""
---> 56         return tuple(xs)
     57
     58     def do_draw(self, data):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/collections.py in <genexpr>(.0)
     58     def do_draw(self, data):
     59         return self.newtuple(
---> 60             data.draw(e) for e in self.element_strategies
     61         )
     62

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    127                 sys.settrace(original_tracer)
    128         else:
--> 129             return self.__draw(strategy)
    130
    131     def __draw(self, strategy):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/strategies.py in do_draw(self, data)
    505             i = data.index
    506             try:
--> 507                 return self.pack(data.draw(self.mapped_strategy))
    508             except UnsatisfiedAssumption:
    509                 if data.index == i:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    127                 sys.settrace(original_tracer)
    128         else:
--> 129             return self.__draw(strategy)
    130
    131     def __draw(self, strategy):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/collections.py in do_draw(self, data)
     58     def do_draw(self, data):
     59         return self.newtuple(
---> 60             data.draw(e) for e in self.element_strategies
     61         )
     62

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/collections.py in newtuple(self, xs)
     54     def newtuple(self, xs):
     55         """Produce a new tuple of the correct type."""
---> 56         return tuple(xs)
     57
     58     def do_draw(self, data):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/collections.py in <genexpr>(.0)
     58     def do_draw(self, data):
     59         return self.newtuple(
---> 60             data.draw(e) for e in self.element_strategies
     61         )
     62

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in draw(self, strategy)
    127                 sys.settrace(original_tracer)
    128         else:
--> 129             return self.__draw(strategy)
    130
    131     def __draw(self, strategy):

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/internal/conjecture/data.py in __draw(self, strategy)
    132         self.start_example()
    133         try:
--> 134             return strategy.do_draw(self)
    135         finally:
    136             if not self.frozen:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/searchstrategy/strategies.py in do_draw(self, data)
    505             i = data.index
    506             try:
--> 507                 return self.pack(data.draw(self.mapped_strategy))
    508             except UnsatisfiedAssumption:
    509                 if data.index == i:

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/strategies.py in <lambda>(value)
    871         kwargs[ms] = from_type(hints[ms])
    872     return tuples(tuples(*args), fixed_dictionaries(kwargs)).map(
--> 873         lambda value: target(*value[0], **value[1])
    874     )
    875

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/strategies.py in lazy_error()
    891
    892             def lazy_error():
--> 893                 raise error
    894
    895             return builds(lazy_error)

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/strategies.py in inner(*args, **kwargs)
    886     def inner(*args, **kwargs):
    887         try:
--> 888             return func(*args, **kwargs)
    889         except Exception as e:
    890             error = e

/Users/daenyth/.pyenv/versions/3.6.1/envs/obs-venv/lib/python3.6/site-packages/hypothesis/strategies.py in from_type(thing)
    938         except ImportError:  # pragma: no cover
    939             pass
--> 940         raise InvalidArgument('thing=%s must be a type' % (thing,))
    941     # Now that we know `thing` is a type, the first step is to check for an
    942     # explicitly registered strategy.  This is the best (and hopefully most

InvalidArgument: thing=<function NewType.<locals>.new_type at 0x107fd40d0> must be a type

[Zac-HD]

Hmm, at runtime NewType is simply the identity function... but the function object is given a __supertype__ attribute we can check - I'll add a special case (as we already do for Union) over the weekend. Thanks for reporting this!