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inspect.signature: Add (restore) support for builtin classes #20473
This commit is contained in:
Yury Selivanov
parent
45e732de70
commit
7d2bfed7a2
295
Lib/inspect.py
295
Lib/inspect.py
@ -1648,6 +1648,139 @@ def _signature_get_bound_param(spec):
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return spec[2:pos]
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def _signature_fromstr(cls, obj, s):
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# Internal helper to parse content of '__text_signature__'
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# and return a Signature based on it
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Parameter = cls._parameter_cls
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if s.endswith("/)"):
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kind = Parameter.POSITIONAL_ONLY
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s = s[:-2] + ')'
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else:
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kind = Parameter.POSITIONAL_OR_KEYWORD
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first_parameter_is_self = s.startswith("($")
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if first_parameter_is_self:
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s = '(' + s[2:]
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s = "def foo" + s + ": pass"
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try:
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module = ast.parse(s)
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except SyntaxError:
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module = None
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if not isinstance(module, ast.Module):
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raise ValueError("{!r} builtin has invalid signature".format(obj))
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f = module.body[0]
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parameters = []
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empty = Parameter.empty
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invalid = object()
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module = None
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module_dict = {}
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module_name = getattr(obj, '__module__', None)
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if module_name:
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module = sys.modules.get(module_name, None)
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if module:
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module_dict = module.__dict__
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sys_module_dict = sys.modules
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def parse_name(node):
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assert isinstance(node, ast.arg)
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if node.annotation != None:
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raise ValueError("Annotations are not currently supported")
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return node.arg
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def wrap_value(s):
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try:
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value = eval(s, module_dict)
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except NameError:
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try:
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value = eval(s, sys_module_dict)
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except NameError:
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raise RuntimeError()
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if isinstance(value, str):
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return ast.Str(value)
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if isinstance(value, (int, float)):
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return ast.Num(value)
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if isinstance(value, bytes):
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return ast.Bytes(value)
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if value in (True, False, None):
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return ast.NameConstant(value)
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raise RuntimeError()
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class RewriteSymbolics(ast.NodeTransformer):
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def visit_Attribute(self, node):
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a = []
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n = node
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while isinstance(n, ast.Attribute):
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a.append(n.attr)
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n = n.value
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if not isinstance(n, ast.Name):
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raise RuntimeError()
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a.append(n.id)
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value = ".".join(reversed(a))
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return wrap_value(value)
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def visit_Name(self, node):
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if not isinstance(node.ctx, ast.Load):
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raise ValueError()
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return wrap_value(node.id)
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def p(name_node, default_node, default=empty):
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name = parse_name(name_node)
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if name is invalid:
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return None
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if default_node and default_node is not _empty:
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try:
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default_node = RewriteSymbolics().visit(default_node)
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o = ast.literal_eval(default_node)
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except ValueError:
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o = invalid
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if o is invalid:
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return None
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default = o if o is not invalid else default
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parameters.append(Parameter(name, kind, default=default, annotation=empty))
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# non-keyword-only parameters
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args = reversed(f.args.args)
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defaults = reversed(f.args.defaults)
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iter = itertools.zip_longest(args, defaults, fillvalue=None)
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for name, default in reversed(list(iter)):
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p(name, default)
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# *args
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if f.args.vararg:
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kind = Parameter.VAR_POSITIONAL
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p(f.args.vararg, empty)
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# keyword-only arguments
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kind = Parameter.KEYWORD_ONLY
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for name, default in zip(f.args.kwonlyargs, f.args.kw_defaults):
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p(name, default)
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# **kwargs
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if f.args.kwarg:
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kind = Parameter.VAR_KEYWORD
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p(f.args.kwarg, empty)
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if first_parameter_is_self:
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assert parameters
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if getattr(obj, '__self__', None):
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# strip off self, it's already been bound
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parameters.pop(0)
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else:
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# for builtins, self parameter is always positional-only!
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p = parameters[0].replace(kind=Parameter.POSITIONAL_ONLY)
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parameters[0] = p
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return cls(parameters, return_annotation=cls.empty)
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def signature(obj):
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'''Get a signature object for the passed callable.'''
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@ -1725,14 +1858,41 @@ def signature(obj):
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sig = signature(init)
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if sig is None:
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# At this point we know, that `obj` is a class, with no user-
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# defined '__init__', '__new__', or class-level '__call__'
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for base in obj.__mro__:
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# Since '__text_signature__' is implemented as a
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# descriptor that extracts text signature from the
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# class docstring, if 'obj' is derived from a builtin
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# class, its own '__text_signature__' may be 'None'.
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# Therefore, we go through the MRO to find the first
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# class with non-empty text signature.
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try:
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text_sig = base.__text_signature__
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except AttributeError:
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pass
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else:
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if text_sig:
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# If 'obj' class has a __text_signature__ attribute:
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# return a signature based on it
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return _signature_fromstr(Signature, obj, text_sig)
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# No '__text_signature__' was found for the 'obj' class.
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# Last option is to check if its '__init__' is
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# object.__init__ or type.__init__.
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if type in obj.__mro__:
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# 'obj' is a metaclass without user-defined __init__
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# or __new__. Return a signature of 'type' builtin.
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return signature(type)
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# or __new__.
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if obj.__init__ is type.__init__:
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# Return a signature of 'type' builtin.
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return signature(type)
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else:
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# We have a class (not metaclass), but no user-defined
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# __init__ or __new__ for it
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return signature(object)
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if obj.__init__ is object.__init__:
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# Return a signature of 'object' builtin.
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return signature(object)
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elif not isinstance(obj, _NonUserDefinedCallables):
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# An object with __call__
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@ -2196,134 +2356,7 @@ class Signature:
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if not s:
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raise ValueError("no signature found for builtin {!r}".format(func))
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Parameter = cls._parameter_cls
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if s.endswith("/)"):
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kind = Parameter.POSITIONAL_ONLY
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s = s[:-2] + ')'
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else:
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kind = Parameter.POSITIONAL_OR_KEYWORD
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first_parameter_is_self = s.startswith("($")
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if first_parameter_is_self:
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s = '(' + s[2:]
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s = "def foo" + s + ": pass"
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try:
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module = ast.parse(s)
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except SyntaxError:
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module = None
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if not isinstance(module, ast.Module):
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raise ValueError("{!r} builtin has invalid signature".format(func))
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f = module.body[0]
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parameters = []
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empty = Parameter.empty
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invalid = object()
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module = None
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module_dict = {}
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module_name = getattr(func, '__module__', None)
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if module_name:
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module = sys.modules.get(module_name, None)
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if module:
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module_dict = module.__dict__
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sys_module_dict = sys.modules
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def parse_name(node):
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assert isinstance(node, ast.arg)
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if node.annotation != None:
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raise ValueError("Annotations are not currently supported")
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return node.arg
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def wrap_value(s):
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try:
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value = eval(s, module_dict)
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except NameError:
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try:
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value = eval(s, sys_module_dict)
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except NameError:
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raise RuntimeError()
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if isinstance(value, str):
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return ast.Str(value)
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if isinstance(value, (int, float)):
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return ast.Num(value)
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if isinstance(value, bytes):
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return ast.Bytes(value)
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if value in (True, False, None):
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return ast.NameConstant(value)
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raise RuntimeError()
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class RewriteSymbolics(ast.NodeTransformer):
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def visit_Attribute(self, node):
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a = []
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n = node
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while isinstance(n, ast.Attribute):
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a.append(n.attr)
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n = n.value
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if not isinstance(n, ast.Name):
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raise RuntimeError()
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a.append(n.id)
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value = ".".join(reversed(a))
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return wrap_value(value)
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def visit_Name(self, node):
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if not isinstance(node.ctx, ast.Load):
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raise ValueError()
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return wrap_value(node.id)
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def p(name_node, default_node, default=empty):
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name = parse_name(name_node)
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if name is invalid:
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return None
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if default_node and default_node is not _empty:
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try:
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default_node = RewriteSymbolics().visit(default_node)
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o = ast.literal_eval(default_node)
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except ValueError:
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o = invalid
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if o is invalid:
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return None
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default = o if o is not invalid else default
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parameters.append(Parameter(name, kind, default=default, annotation=empty))
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# non-keyword-only parameters
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args = reversed(f.args.args)
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defaults = reversed(f.args.defaults)
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iter = itertools.zip_longest(args, defaults, fillvalue=None)
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for name, default in reversed(list(iter)):
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p(name, default)
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# *args
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if f.args.vararg:
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kind = Parameter.VAR_POSITIONAL
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p(f.args.vararg, empty)
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# keyword-only arguments
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kind = Parameter.KEYWORD_ONLY
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for name, default in zip(f.args.kwonlyargs, f.args.kw_defaults):
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p(name, default)
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# **kwargs
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if f.args.kwarg:
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kind = Parameter.VAR_KEYWORD
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p(f.args.kwarg, empty)
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if first_parameter_is_self:
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assert parameters
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if getattr(func, '__self__', None):
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# strip off self, it's already been bound
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parameters.pop(0)
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else:
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# for builtins, self parameter is always positional-only!
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p = parameters[0].replace(kind=Parameter.POSITIONAL_ONLY)
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parameters[0] = p
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return cls(parameters, return_annotation=cls.empty)
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return _signature_fromstr(cls, func, s)
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@property
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def parameters(self):
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@ -2210,6 +2210,32 @@ class TestSignatureObject(unittest.TestCase):
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self.assertEqual(str(inspect.signature(D)),
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'(object_or_name, bases, dict)')
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@unittest.skipIf(MISSING_C_DOCSTRINGS,
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"Signature information for builtins requires docstrings")
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def test_signature_on_builtin_class(self):
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self.assertEqual(str(inspect.signature(_pickle.Pickler)),
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'(file, protocol=None, fix_imports=True)')
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class P(_pickle.Pickler): pass
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class EmptyTrait: pass
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class P2(EmptyTrait, P): pass
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self.assertEqual(str(inspect.signature(P)),
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'(file, protocol=None, fix_imports=True)')
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self.assertEqual(str(inspect.signature(P2)),
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'(file, protocol=None, fix_imports=True)')
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class P3(P2):
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def __init__(self, spam):
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pass
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self.assertEqual(str(inspect.signature(P3)), '(spam)')
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class MetaP(type):
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def __call__(cls, foo, bar):
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pass
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class P4(P2, metaclass=MetaP):
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pass
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self.assertEqual(str(inspect.signature(P4)), '(foo, bar)')
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def test_signature_on_callable_objects(self):
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class Foo:
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def __call__(self, a):
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