# Authors: Sylvain MARIE <sylvain.marie@se.com>

# + All contributors to <https://github.com/smarie/python-pytest-cases>

#

# License: 3-clause BSD, <https://github.com/smarie/python-pytest-cases/blob/master/LICENSE>

from __future__ import division

from inspect import getmodule, currentframe

from warnings import warn

try:

# type hints, python 3+

from typing import Callable, Any, Union, Iterable # noqa

from types import ModuleType # noqa

except ImportError:

pass

from .common_others import make_identifier

class ExistingFixtureNameError(ValueError):

"""

Raised by `add_fixture_to_callers_module` when a fixture already exists in a module

"""

def __init__(self, module, name, caller):

self.module = module

self.name = name

self.caller = caller

def __str__(self):

return f"Symbol `{self.name}` already exists in module {self.module} and therefore a corresponding " \

f"fixture can not be created by `{self.caller}`"

RAISE = 0

WARN = 1

CHANGE = 2

def check_name_available(module,

name, # type: str

if_name_exists=RAISE, # type: int

name_changer=None, # type: Callable

caller=None, # type: Callable[[Any], Any]

extra_forbidden_names=() # type: Iterable[str]

):

"""

Routine to check that a name is not already in dir(module) + extra_forbidden_names.

The `if_name_exists` argument allows users to specify what happens if a name exists already.

`if_name_exists=CHANGE` allows users to ask for a new non-conflicting name to be found and returned.

:param module: a module or a class. dir(module) + extra_forbidden_names is used as a reference of forbidden names

:param name: proposed name, to check against existent names in module

:param if_name_exists: policy to apply if name already exists in dir(module) + extra_forbidden_names

:param name_changer: an optional custom name changer function for new names to be generated

:param caller: for warning / error messages. Something identifying the caller

:param extra_forbidden_names: a reference list of additional forbidden names that can be provided, in addition to

dir(module)

:return: a name that might be different if policy was CHANGE

"""

new_name = make_identifier(name)

if new_name != name:

if if_name_exists is RAISE:

raise ValueError(f"Proposed name is an invalid identifier: {name}")

elif if_name_exists is WARN:

warn(f"{name} name was not a valid identifier, changed it to {new_name}")

name = new_name

if name_changer is None:

# default style for name changing. i starts with 1

def name_changer(name, i):

return f'{name}_{i}'

ref_list = dir(module) + list(extra_forbidden_names)

if name in ref_list:

if caller is None:

caller = ''

# Name already exists: act according to policy

if if_name_exists is RAISE:

raise ExistingFixtureNameError(module, name, caller)

elif if_name_exists is WARN:

warn(f"{caller} Overriding symbol {name} in module {module}")

elif if_name_exists is CHANGE:

# find a non-used name in that module

i = 1

name2 = name_changer(name, i)

while name2 in ref_list:

i += 1

name2 = name_changer(name, i)

name = name2

else:

raise ValueError(f"invalid value for `if_name_exists`: {if_name_exists}")

return name

def get_caller_module(frame_offset=1):

# type: (...) -> ModuleType

""" Return the module where the last frame belongs.

:param frame_offset: an alternate offset to look further up in the call stack

:return:

"""

# grab context from the caller frame

frame = _get_callerframe(offset=frame_offset)

return getmodule(frame)

def _get_callerframe(offset=0):

""" Return a frame in the call stack

:param offset: an alternate offset to look further up in the call stack

:return:

"""

# inspect.stack is extremely slow, the fastest is sys._getframe or inspect.currentframe().

# See https://gist.github.com/JettJones/c236494013f22723c1822126df944b12

# frame = sys._getframe(2 + offset)

frame = currentframe()

for _ in range(2 + offset):

frame = frame.f_back

return frame