diff options
Diffstat (limited to 'Lib/inspect.py')
| -rw-r--r-- | Lib/inspect.py | 149 |
1 files changed, 135 insertions, 14 deletions
diff --git a/Lib/inspect.py b/Lib/inspect.py index b8e247ec25..9f8cc01310 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -24,6 +24,8 @@ Here are some of the useful functions provided by this module: stack(), trace() - get info about frames on the stack or in a traceback signature() - get a Signature object for the callable + + get_annotations() - safely compute an object's annotations """ # This module is in the public domain. No warranties. @@ -60,6 +62,122 @@ for k, v in dis.COMPILER_FLAG_NAMES.items(): # See Include/object.h TPFLAGS_IS_ABSTRACT = 1 << 20 + +def get_annotations(obj, *, globals=None, locals=None, eval_str=False): + """Compute the annotations dict for an object. + + obj may be a callable, class, or module. + Passing in an object of any other type raises TypeError. + + Returns a dict. get_annotations() returns a new dict every time + it's called; calling it twice on the same object will return two + different but equivalent dicts. + + This function handles several details for you: + + * If eval_str is true, values of type str will + be un-stringized using eval(). This is intended + for use with stringized annotations + ("from __future__ import annotations"). + * If obj doesn't have an annotations dict, returns an + empty dict. (Functions and methods always have an + annotations dict; classes, modules, and other types of + callables may not.) + * Ignores inherited annotations on classes. If a class + doesn't have its own annotations dict, returns an empty dict. + * All accesses to object members and dict values are done + using getattr() and dict.get() for safety. + * Always, always, always returns a freshly-created dict. + + eval_str controls whether or not values of type str are replaced + with the result of calling eval() on those values: + + * If eval_str is true, eval() is called on values of type str. + * If eval_str is false (the default), values of type str are unchanged. + + globals and locals are passed in to eval(); see the documentation + for eval() for more information. If either globals or locals is + None, this function may replace that value with a context-specific + default, contingent on type(obj): + + * If obj is a module, globals defaults to obj.__dict__. + * If obj is a class, globals defaults to + sys.modules[obj.__module__].__dict__ and locals + defaults to the obj class namespace. + * If obj is a callable, globals defaults to obj.__globals__, + although if obj is a wrapped function (using + functools.update_wrapper()) it is first unwrapped. + """ + if isinstance(obj, type): + # class + obj_dict = getattr(obj, '__dict__', None) + if obj_dict and hasattr(obj_dict, 'get'): + ann = obj_dict.get('__annotations__', None) + if isinstance(ann, types.GetSetDescriptorType): + ann = None + else: + ann = None + + obj_globals = None + module_name = getattr(obj, '__module__', None) + if module_name: + module = sys.modules.get(module_name, None) + if module: + obj_globals = getattr(module, '__dict__', None) + obj_locals = dict(vars(obj)) + unwrap = obj + elif isinstance(obj, types.ModuleType): + # module + ann = getattr(obj, '__annotations__', None) + obj_globals = getattr(obj, '__dict__') + obj_locals = None + unwrap = None + elif callable(obj): + # this includes types.Function, types.BuiltinFunctionType, + # types.BuiltinMethodType, functools.partial, functools.singledispatch, + # "class funclike" from Lib/test/test_inspect... on and on it goes. + ann = getattr(obj, '__annotations__', None) + obj_globals = getattr(obj, '__globals__', None) + obj_locals = None + unwrap = obj + else: + raise TypeError(f"{obj!r} is not a module, class, or callable.") + + if ann is None: + return {} + + if not isinstance(ann, dict): + raise ValueError(f"{obj!r}.__annotations__ is neither a dict nor None") + + if not ann: + return {} + + if not eval_str: + return dict(ann) + + if unwrap is not None: + while True: + if hasattr(unwrap, '__wrapped__'): + unwrap = unwrap.__wrapped__ + continue + if isinstance(unwrap, functools.partial): + unwrap = unwrap.func + continue + break + if hasattr(unwrap, "__globals__"): + obj_globals = unwrap.__globals__ + + if globals is None: + globals = obj_globals + if locals is None: + locals = obj_locals + + return_value = {key: + value if not isinstance(value, str) else eval(value, globals, locals) + for key, value in ann.items() } + return return_value + + # ----------------------------------------------------------- type-checking def ismodule(object): """Return true if the object is a module. @@ -1165,7 +1283,8 @@ def getfullargspec(func): sig = _signature_from_callable(func, follow_wrapper_chains=False, skip_bound_arg=False, - sigcls=Signature) + sigcls=Signature, + eval_str=False) except Exception as ex: # Most of the times 'signature' will raise ValueError. # But, it can also raise AttributeError, and, maybe something @@ -1898,7 +2017,7 @@ def _signature_is_functionlike(obj): isinstance(name, str) and (defaults is None or isinstance(defaults, tuple)) and (kwdefaults is None or isinstance(kwdefaults, dict)) and - isinstance(annotations, dict)) + (isinstance(annotations, (dict)) or annotations is None) ) def _signature_get_bound_param(spec): @@ -2151,7 +2270,7 @@ def _signature_from_builtin(cls, func, skip_bound_arg=True): def _signature_from_function(cls, func, skip_bound_arg=True, - globalns=None, localns=None): + globals=None, locals=None, eval_str=False): """Private helper: constructs Signature for the given python function.""" is_duck_function = False @@ -2177,7 +2296,7 @@ def _signature_from_function(cls, func, skip_bound_arg=True, positional = arg_names[:pos_count] keyword_only_count = func_code.co_kwonlyargcount keyword_only = arg_names[pos_count:pos_count + keyword_only_count] - annotations = func.__annotations__ + annotations = get_annotations(func, globals=globals, locals=locals, eval_str=eval_str) defaults = func.__defaults__ kwdefaults = func.__kwdefaults__ @@ -2248,8 +2367,9 @@ def _signature_from_function(cls, func, skip_bound_arg=True, def _signature_from_callable(obj, *, follow_wrapper_chains=True, skip_bound_arg=True, - globalns=None, - localns=None, + globals=None, + locals=None, + eval_str=False, sigcls): """Private helper function to get signature for arbitrary @@ -2259,9 +2379,10 @@ def _signature_from_callable(obj, *, _get_signature_of = functools.partial(_signature_from_callable, follow_wrapper_chains=follow_wrapper_chains, skip_bound_arg=skip_bound_arg, - globalns=globalns, - localns=localns, - sigcls=sigcls) + globals=globals, + locals=locals, + sigcls=sigcls, + eval_str=eval_str) if not callable(obj): raise TypeError('{!r} is not a callable object'.format(obj)) @@ -2330,7 +2451,7 @@ def _signature_from_callable(obj, *, # of a Python function (Cython functions, for instance), then: return _signature_from_function(sigcls, obj, skip_bound_arg=skip_bound_arg, - globalns=globalns, localns=localns) + globals=globals, locals=locals, eval_str=eval_str) if _signature_is_builtin(obj): return _signature_from_builtin(sigcls, obj, @@ -2854,11 +2975,11 @@ class Signature: @classmethod def from_callable(cls, obj, *, - follow_wrapped=True, globalns=None, localns=None): + follow_wrapped=True, globals=None, locals=None, eval_str=False): """Constructs Signature for the given callable object.""" return _signature_from_callable(obj, sigcls=cls, follow_wrapper_chains=follow_wrapped, - globalns=globalns, localns=localns) + globals=globals, locals=locals, eval_str=eval_str) @property def parameters(self): @@ -3106,10 +3227,10 @@ class Signature: return rendered -def signature(obj, *, follow_wrapped=True, globalns=None, localns=None): +def signature(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=False): """Get a signature object for the passed callable.""" return Signature.from_callable(obj, follow_wrapped=follow_wrapped, - globalns=globalns, localns=localns) + globals=globals, locals=locals, eval_str=eval_str) def _main(): |