"""Tests for stubs. Verify that various things in stubs are consistent with how things behave at runtime. """ import argparse import copy import enum import importlib import inspect import os import pkgutil import re import sys import types import typing import typing_extensions import warnings from contextlib import redirect_stdout, redirect_stderr from functools import singledispatch from pathlib import Path from typing import Any, Dict, Generic, Iterator, List, Optional, Tuple, TypeVar, Union, cast from typing_extensions import Type import mypy.build import mypy.modulefinder import mypy.state import mypy.types import mypy.version from mypy import nodes from mypy.config_parser import parse_config_file from mypy.options import Options from mypy.util import FancyFormatter, bytes_to_human_readable_repr, plural_s, is_dunder class Missing: """Marker object for things that are missing (from a stub or the runtime).""" def __repr__(self) -> str: return "MISSING" MISSING = Missing() T = TypeVar("T") MaybeMissing = Union[T, Missing] _formatter = FancyFormatter(sys.stdout, sys.stderr, False) def _style(message: str, **kwargs: Any) -> str: """Wrapper around mypy.util for fancy formatting.""" kwargs.setdefault("color", "none") return _formatter.style(message, **kwargs) def _truncate(message: str, length: int) -> str: if len(message) > length: return message[:length - 3] + "..." return message class StubtestFailure(Exception): pass class Error: def __init__( self, object_path: List[str], message: str, stub_object: MaybeMissing[nodes.Node], runtime_object: MaybeMissing[Any], *, stub_desc: Optional[str] = None, runtime_desc: Optional[str] = None ) -> None: """Represents an error found by stubtest. :param object_path: Location of the object with the error, e.g. ``["module", "Class", "method"]`` :param message: Error message :param stub_object: The mypy node representing the stub :param runtime_object: Actual object obtained from the runtime :param stub_desc: Specialised description for the stub object, should you wish :param runtime_desc: Specialised description for the runtime object, should you wish """ self.object_desc = ".".join(object_path) self.message = message self.stub_object = stub_object self.runtime_object = runtime_object self.stub_desc = stub_desc or str(getattr(stub_object, "type", stub_object)) self.runtime_desc = runtime_desc or _truncate(repr(runtime_object), 100) def is_missing_stub(self) -> bool: """Whether or not the error is for something missing from the stub.""" return isinstance(self.stub_object, Missing) def is_positional_only_related(self) -> bool: """Whether or not the error is for something being (or not being) positional-only.""" # TODO: This is hacky, use error codes or something more resilient return "leading double underscore" in self.message def get_description(self, concise: bool = False) -> str: """Returns a description of the error. :param concise: Whether to return a concise, one-line description """ if concise: return _style(self.object_desc, bold=True) + " " + self.message stub_line = None stub_file: None = None if not isinstance(self.stub_object, Missing): stub_line = self.stub_object.line # TODO: Find a way of getting the stub file stub_loc_str = "" if stub_line: stub_loc_str += f" at line {stub_line}" if stub_file: stub_loc_str += f" in file {Path(stub_file)}" runtime_line = None runtime_file = None if not isinstance(self.runtime_object, Missing): try: runtime_line = inspect.getsourcelines(self.runtime_object)[1] except (OSError, TypeError): pass try: runtime_file = inspect.getsourcefile(self.runtime_object) except TypeError: pass runtime_loc_str = "" if runtime_line: runtime_loc_str += f" at line {runtime_line}" if runtime_file: runtime_loc_str += f" in file {Path(runtime_file)}" output = [ _style("error: ", color="red", bold=True), _style(self.object_desc, bold=True), " ", self.message, "\n", "Stub:", _style(stub_loc_str, dim=True), "\n", _style(self.stub_desc + "\n", color="blue", dim=True), "Runtime:", _style(runtime_loc_str, dim=True), "\n", _style(self.runtime_desc + "\n", color="blue", dim=True), ] return "".join(output) # ==================== # Core logic # ==================== def silent_import_module(module_name: str) -> types.ModuleType: with open(os.devnull, "w") as devnull: with warnings.catch_warnings(), redirect_stdout(devnull), redirect_stderr(devnull): warnings.simplefilter("ignore") runtime = importlib.import_module(module_name) # Also run the equivalent of `from module import *` # This could have the additional effect of loading not-yet-loaded submodules # mentioned in __all__ __import__(module_name, fromlist=["*"]) return runtime def test_module(module_name: str) -> Iterator[Error]: """Tests a given module's stub against introspecting it at runtime. Requires the stub to have been built already, accomplished by a call to ``build_stubs``. :param module_name: The module to test """ stub = get_stub(module_name) if stub is None: runtime_desc = repr(sys.modules[module_name]) if module_name in sys.modules else "N/A" yield Error( [module_name], "failed to find stubs", MISSING, None, runtime_desc=runtime_desc ) return try: runtime = silent_import_module(module_name) except Exception as e: yield Error([module_name], f"failed to import, {type(e).__name__}: {e}", stub, MISSING) return with warnings.catch_warnings(): warnings.simplefilter("ignore") yield from verify(stub, runtime, [module_name]) @singledispatch def verify( stub: MaybeMissing[nodes.Node], runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: """Entry point for comparing a stub to a runtime object. We use single dispatch based on the type of ``stub``. :param stub: The mypy node representing a part of the stub :param runtime: The runtime object corresponding to ``stub`` """ yield Error(object_path, "is an unknown mypy node", stub, runtime) @verify.register(nodes.MypyFile) def verify_mypyfile( stub: nodes.MypyFile, runtime: MaybeMissing[types.ModuleType], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): yield Error(object_path, "is not present at runtime", stub, runtime) return if not isinstance(runtime, types.ModuleType): yield Error(object_path, "is not a module", stub, runtime) return # Check things in the stub to_check = { m for m, o in stub.names.items() if not o.module_hidden and (not is_probably_private(m) or hasattr(runtime, m)) } def _belongs_to_runtime(r: types.ModuleType, attr: str) -> bool: obj = getattr(r, attr) try: obj_mod = getattr(obj, "__module__", None) except Exception: return False if obj_mod is not None: return obj_mod == r.__name__ return not isinstance(obj, types.ModuleType) runtime_public_contents = ( runtime.__all__ if hasattr(runtime, "__all__") else [ m for m in dir(runtime) if not is_probably_private(m) # Ensure that the object's module is `runtime`, since in the absence of __all__ we # don't have a good way to detect re-exports at runtime. and _belongs_to_runtime(runtime, m) ] ) # Check all things declared in module's __all__, falling back to our best guess to_check.update(runtime_public_contents) to_check.difference_update(IGNORED_MODULE_DUNDERS) for entry in sorted(to_check): stub_entry = stub.names[entry].node if entry in stub.names else MISSING if isinstance(stub_entry, nodes.MypyFile): # Don't recursively check exported modules, since that leads to infinite recursion continue assert stub_entry is not None try: runtime_entry = getattr(runtime, entry, MISSING) except Exception: # Catch all exceptions in case the runtime raises an unexpected exception # from __getattr__ or similar. continue yield from verify(stub_entry, runtime_entry, object_path + [entry]) if sys.version_info >= (3, 7): _WrapperDescriptorType = types.WrapperDescriptorType else: _WrapperDescriptorType = type(object.__init__) @verify.register(nodes.TypeInfo) def verify_typeinfo( stub: nodes.TypeInfo, runtime: MaybeMissing[Type[Any]], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): yield Error(object_path, "is not present at runtime", stub, runtime, stub_desc=repr(stub)) return if not isinstance(runtime, type): yield Error(object_path, "is not a type", stub, runtime, stub_desc=repr(stub)) return try: class SubClass(runtime): # type: ignore pass except TypeError: # Enum classes are implicitly @final if not stub.is_final and not issubclass(runtime, enum.Enum): yield Error( object_path, "cannot be subclassed at runtime, but isn't marked with @final in the stub", stub, runtime, stub_desc=repr(stub), ) except Exception: # The class probably wants its subclasses to do something special. # Examples: ctypes.Array, ctypes._SimpleCData pass # Check everything already defined on the stub class itself (i.e. not inherited) to_check = set(stub.names) # Check all public things on the runtime class to_check.update( # cast to workaround mypyc complaints m for m in cast(Any, vars)(runtime) if not is_probably_private(m) and m not in IGNORABLE_CLASS_DUNDERS ) for entry in sorted(to_check): mangled_entry = entry if entry.startswith("__") and not entry.endswith("__"): mangled_entry = f"_{stub.name}{entry}" stub_to_verify = next((t.names[entry].node for t in stub.mro if entry in t.names), MISSING) assert stub_to_verify is not None try: runtime_attr = getattr(runtime, mangled_entry, MISSING) except Exception: # Catch all exceptions in case the runtime raises an unexpected exception # from __getattr__ or similar. continue # Do not error for an object missing from the stub # If the runtime object is a types.WrapperDescriptorType object # and has a non-special dunder name. # The vast majority of these are false positives. if not ( isinstance(stub_to_verify, Missing) and isinstance(runtime_attr, _WrapperDescriptorType) and is_dunder(mangled_entry, exclude_special=True) ): yield from verify(stub_to_verify, runtime_attr, object_path + [entry]) def _verify_static_class_methods( stub: nodes.FuncBase, runtime: Any, object_path: List[str] ) -> Iterator[str]: if stub.name in ("__new__", "__init_subclass__", "__class_getitem__"): # Special cased by Python, so don't bother checking return if inspect.isbuiltin(runtime): # The isinstance checks don't work reliably for builtins, e.g. datetime.datetime.now, so do # something a little hacky that seems to work well probably_class_method = isinstance(getattr(runtime, "__self__", None), type) if probably_class_method and not stub.is_class: yield "runtime is a classmethod but stub is not" if not probably_class_method and stub.is_class: yield "stub is a classmethod but runtime is not" return # Look the object up statically, to avoid binding by the descriptor protocol static_runtime = importlib.import_module(object_path[0]) for entry in object_path[1:]: try: static_runtime = inspect.getattr_static(static_runtime, entry) except AttributeError: # This can happen with mangled names, ignore for now. # TODO: pass more information about ancestors of nodes/objects to verify, so we don't # have to do this hacky lookup. Would be useful in a couple other places too. return if isinstance(static_runtime, classmethod) and not stub.is_class: yield "runtime is a classmethod but stub is not" if not isinstance(static_runtime, classmethod) and stub.is_class: yield "stub is a classmethod but runtime is not" if isinstance(static_runtime, staticmethod) and not stub.is_static: yield "runtime is a staticmethod but stub is not" if not isinstance(static_runtime, staticmethod) and stub.is_static: yield "stub is a staticmethod but runtime is not" def _verify_arg_name( stub_arg: nodes.Argument, runtime_arg: inspect.Parameter, function_name: str ) -> Iterator[str]: """Checks whether argument names match.""" # Ignore exact names for most dunder methods if is_dunder(function_name, exclude_special=True): return def strip_prefix(s: str, prefix: str) -> str: return s[len(prefix):] if s.startswith(prefix) else s if strip_prefix(stub_arg.variable.name, "__") == runtime_arg.name: return def names_approx_match(a: str, b: str) -> bool: a = a.strip("_") b = b.strip("_") return a.startswith(b) or b.startswith(a) or len(a) == 1 or len(b) == 1 # Be more permissive about names matching for positional-only arguments if runtime_arg.kind == inspect.Parameter.POSITIONAL_ONLY and names_approx_match( stub_arg.variable.name, runtime_arg.name ): return # This comes up with namedtuples, so ignore if stub_arg.variable.name == "_self": return yield ( 'stub argument "{}" differs from runtime argument "{}"'.format( stub_arg.variable.name, runtime_arg.name ) ) def _verify_arg_default_value( stub_arg: nodes.Argument, runtime_arg: inspect.Parameter ) -> Iterator[str]: """Checks whether argument default values are compatible.""" if runtime_arg.default != inspect.Parameter.empty: if stub_arg.kind.is_required(): yield ( 'runtime argument "{}" has a default value but stub argument does not'.format( runtime_arg.name ) ) else: runtime_type = get_mypy_type_of_runtime_value(runtime_arg.default) # Fallback to the type annotation type if var type is missing. The type annotation # is an UnboundType, but I don't know enough to know what the pros and cons here are. # UnboundTypes have ugly question marks following them, so default to var type. # Note we do this same fallback when constructing signatures in from_overloadedfuncdef stub_type = stub_arg.variable.type or stub_arg.type_annotation if isinstance(stub_type, mypy.types.TypeVarType): stub_type = stub_type.upper_bound if ( runtime_type is not None and stub_type is not None # Avoid false positives for marker objects and type(runtime_arg.default) != object # And ellipsis and runtime_arg.default is not ... and not is_subtype_helper(runtime_type, stub_type) ): yield ( 'runtime argument "{}" has a default value of type {}, ' "which is incompatible with stub argument type {}".format( runtime_arg.name, runtime_type, stub_type ) ) else: if stub_arg.kind.is_optional(): yield ( 'stub argument "{}" has a default value but runtime argument does not'.format( stub_arg.variable.name ) ) def maybe_strip_cls(name: str, args: List[nodes.Argument]) -> List[nodes.Argument]: if name in ("__init_subclass__", "__class_getitem__"): # These are implicitly classmethods. If the stub chooses not to have @classmethod, we # should remove the cls argument if args[0].variable.name == "cls": return args[1:] return args class Signature(Generic[T]): def __init__(self) -> None: self.pos: List[T] = [] self.kwonly: Dict[str, T] = {} self.varpos: Optional[T] = None self.varkw: Optional[T] = None def __str__(self) -> str: def get_name(arg: Any) -> str: if isinstance(arg, inspect.Parameter): return arg.name if isinstance(arg, nodes.Argument): return arg.variable.name raise AssertionError def get_type(arg: Any) -> Optional[str]: if isinstance(arg, inspect.Parameter): return None if isinstance(arg, nodes.Argument): return str(arg.variable.type or arg.type_annotation) raise AssertionError def has_default(arg: Any) -> bool: if isinstance(arg, inspect.Parameter): return arg.default != inspect.Parameter.empty if isinstance(arg, nodes.Argument): return arg.kind.is_optional() raise AssertionError def get_desc(arg: Any) -> str: arg_type = get_type(arg) return ( get_name(arg) + (f": {arg_type}" if arg_type else "") + (" = ..." if has_default(arg) else "") ) kw_only = sorted(self.kwonly.values(), key=lambda a: (has_default(a), get_name(a))) ret = "def (" ret += ", ".join( [get_desc(arg) for arg in self.pos] + (["*" + get_name(self.varpos)] if self.varpos else (["*"] if self.kwonly else [])) + [get_desc(arg) for arg in kw_only] + (["**" + get_name(self.varkw)] if self.varkw else []) ) ret += ")" return ret @staticmethod def from_funcitem(stub: nodes.FuncItem) -> "Signature[nodes.Argument]": stub_sig: Signature[nodes.Argument] = Signature() stub_args = maybe_strip_cls(stub.name, stub.arguments) for stub_arg in stub_args: if stub_arg.kind.is_positional(): stub_sig.pos.append(stub_arg) elif stub_arg.kind.is_named(): stub_sig.kwonly[stub_arg.variable.name] = stub_arg elif stub_arg.kind == nodes.ARG_STAR: stub_sig.varpos = stub_arg elif stub_arg.kind == nodes.ARG_STAR2: stub_sig.varkw = stub_arg else: raise AssertionError return stub_sig @staticmethod def from_inspect_signature(signature: inspect.Signature) -> "Signature[inspect.Parameter]": runtime_sig: Signature[inspect.Parameter] = Signature() for runtime_arg in signature.parameters.values(): if runtime_arg.kind in ( inspect.Parameter.POSITIONAL_ONLY, inspect.Parameter.POSITIONAL_OR_KEYWORD, ): runtime_sig.pos.append(runtime_arg) elif runtime_arg.kind == inspect.Parameter.KEYWORD_ONLY: runtime_sig.kwonly[runtime_arg.name] = runtime_arg elif runtime_arg.kind == inspect.Parameter.VAR_POSITIONAL: runtime_sig.varpos = runtime_arg elif runtime_arg.kind == inspect.Parameter.VAR_KEYWORD: runtime_sig.varkw = runtime_arg else: raise AssertionError return runtime_sig @staticmethod def from_overloadedfuncdef(stub: nodes.OverloadedFuncDef) -> "Signature[nodes.Argument]": """Returns a Signature from an OverloadedFuncDef. If life were simple, to verify_overloadedfuncdef, we'd just verify_funcitem for each of its items. Unfortunately, life isn't simple and overloads are pretty deceitful. So instead, we try and combine the overload's items into a single signature that is compatible with any lies it might try to tell. """ # For most dunder methods, just assume all args are positional-only assume_positional_only = is_dunder(stub.name, exclude_special=True) all_args: Dict[str, List[Tuple[nodes.Argument, int]]] = {} for func in map(_resolve_funcitem_from_decorator, stub.items): assert func is not None args = maybe_strip_cls(stub.name, func.arguments) for index, arg in enumerate(args): # For positional-only args, we allow overloads to have different names for the same # argument. To accomplish this, we just make up a fake index-based name. name = ( f"__{index}" if arg.variable.name.startswith("__") or assume_positional_only else arg.variable.name ) all_args.setdefault(name, []).append((arg, index)) def get_position(arg_name: str) -> int: # We just need this to return the positional args in the correct order. return max(index for _, index in all_args[arg_name]) def get_type(arg_name: str) -> mypy.types.ProperType: with mypy.state.state.strict_optional_set(True): all_types = [ arg.variable.type or arg.type_annotation for arg, _ in all_args[arg_name] ] return mypy.typeops.make_simplified_union([t for t in all_types if t]) def get_kind(arg_name: str) -> nodes.ArgKind: kinds = {arg.kind for arg, _ in all_args[arg_name]} if nodes.ARG_STAR in kinds: return nodes.ARG_STAR if nodes.ARG_STAR2 in kinds: return nodes.ARG_STAR2 # The logic here is based on two tenets: # 1) If an arg is ever optional (or unspecified), it is optional # 2) If an arg is ever positional, it is positional is_opt = ( len(all_args[arg_name]) < len(stub.items) or nodes.ARG_OPT in kinds or nodes.ARG_NAMED_OPT in kinds ) is_pos = nodes.ARG_OPT in kinds or nodes.ARG_POS in kinds if is_opt: return nodes.ARG_OPT if is_pos else nodes.ARG_NAMED_OPT return nodes.ARG_POS if is_pos else nodes.ARG_NAMED sig: Signature[nodes.Argument] = Signature() for arg_name in sorted(all_args, key=get_position): # example_arg_name gives us a real name (in case we had a fake index-based name) example_arg_name = all_args[arg_name][0][0].variable.name arg = nodes.Argument( nodes.Var(example_arg_name, get_type(arg_name)), type_annotation=None, initializer=None, kind=get_kind(arg_name), ) if arg.kind.is_positional(): sig.pos.append(arg) elif arg.kind.is_named(): sig.kwonly[arg.variable.name] = arg elif arg.kind == nodes.ARG_STAR: sig.varpos = arg elif arg.kind == nodes.ARG_STAR2: sig.varkw = arg else: raise AssertionError return sig def _verify_signature( stub: Signature[nodes.Argument], runtime: Signature[inspect.Parameter], function_name: str ) -> Iterator[str]: # Check positional arguments match up for stub_arg, runtime_arg in zip(stub.pos, runtime.pos): yield from _verify_arg_name(stub_arg, runtime_arg, function_name) yield from _verify_arg_default_value(stub_arg, runtime_arg) if ( runtime_arg.kind == inspect.Parameter.POSITIONAL_ONLY and not stub_arg.variable.name.startswith("__") and not stub_arg.variable.name.strip("_") == "self" and not is_dunder(function_name, exclude_special=True) # noisy for dunder methods ): yield ( 'stub argument "{}" should be positional-only ' '(rename with a leading double underscore, i.e. "__{}")'.format( stub_arg.variable.name, runtime_arg.name ) ) if ( runtime_arg.kind != inspect.Parameter.POSITIONAL_ONLY and stub_arg.variable.name.startswith("__") and not is_dunder(function_name, exclude_special=True) # noisy for dunder methods ): yield ( 'stub argument "{}" should be positional or keyword ' "(remove leading double underscore)".format(stub_arg.variable.name) ) # Check unmatched positional args if len(stub.pos) > len(runtime.pos): # There are cases where the stub exhaustively lists out the extra parameters the function # would take through *args. Hence, a) we can't check that the runtime actually takes those # parameters and b) below, we don't enforce that the stub takes *args, since runtime logic # may prevent those arguments from actually being accepted. if runtime.varpos is None: for stub_arg in stub.pos[len(runtime.pos):]: # If the variable is in runtime.kwonly, it's just mislabelled as not a # keyword-only argument if stub_arg.variable.name not in runtime.kwonly: yield f'runtime does not have argument "{stub_arg.variable.name}"' else: yield f'stub argument "{stub_arg.variable.name}" is not keyword-only' if stub.varpos is not None: yield f'runtime does not have *args argument "{stub.varpos.variable.name}"' elif len(stub.pos) < len(runtime.pos): for runtime_arg in runtime.pos[len(stub.pos):]: if runtime_arg.name not in stub.kwonly: yield f'stub does not have argument "{runtime_arg.name}"' else: yield f'runtime argument "{runtime_arg.name}" is not keyword-only' # Checks involving *args if len(stub.pos) <= len(runtime.pos) or runtime.varpos is None: if stub.varpos is None and runtime.varpos is not None: yield f'stub does not have *args argument "{runtime.varpos.name}"' if stub.varpos is not None and runtime.varpos is None: yield f'runtime does not have *args argument "{stub.varpos.variable.name}"' # Check keyword-only args for arg in sorted(set(stub.kwonly) & set(runtime.kwonly)): stub_arg, runtime_arg = stub.kwonly[arg], runtime.kwonly[arg] yield from _verify_arg_name(stub_arg, runtime_arg, function_name) yield from _verify_arg_default_value(stub_arg, runtime_arg) # Check unmatched keyword-only args if runtime.varkw is None or not set(runtime.kwonly).issubset(set(stub.kwonly)): # There are cases where the stub exhaustively lists out the extra parameters the function # would take through *kwargs. Hence, a) we only check if the runtime actually takes those # parameters when the above condition holds and b) below, we don't enforce that the stub # takes *kwargs, since runtime logic may prevent additional arguments from actually being # accepted. for arg in sorted(set(stub.kwonly) - set(runtime.kwonly)): yield f'runtime does not have argument "{arg}"' for arg in sorted(set(runtime.kwonly) - set(stub.kwonly)): if arg in {stub_arg.variable.name for stub_arg in stub.pos}: # Don't report this if we've reported it before if len(stub.pos) > len(runtime.pos) and runtime.varpos is not None: yield f'stub argument "{arg}" is not keyword-only' else: yield f'stub does not have argument "{arg}"' # Checks involving **kwargs if stub.varkw is None and runtime.varkw is not None: # As mentioned above, don't enforce that the stub takes **kwargs. # Also check against positional parameters, to avoid a nitpicky message when an argument # isn't marked as keyword-only stub_pos_names = {stub_arg.variable.name for stub_arg in stub.pos} # Ideally we'd do a strict subset check, but in practice the errors from that aren't useful if not set(runtime.kwonly).issubset(set(stub.kwonly) | stub_pos_names): yield f'stub does not have **kwargs argument "{runtime.varkw.name}"' if stub.varkw is not None and runtime.varkw is None: yield f'runtime does not have **kwargs argument "{stub.varkw.variable.name}"' @verify.register(nodes.FuncItem) def verify_funcitem( stub: nodes.FuncItem, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): yield Error(object_path, "is not present at runtime", stub, runtime) return if not is_probably_a_function(runtime): yield Error(object_path, "is not a function", stub, runtime) if not callable(runtime): return for message in _verify_static_class_methods(stub, runtime, object_path): yield Error(object_path, "is inconsistent, " + message, stub, runtime) signature = safe_inspect_signature(runtime) runtime_is_coroutine = inspect.iscoroutinefunction(runtime) if signature: stub_sig = Signature.from_funcitem(stub) runtime_sig = Signature.from_inspect_signature(signature) runtime_sig_desc = f'{"async " if runtime_is_coroutine else ""}def {signature}' stub_desc = f'def {stub_sig!r}' else: runtime_sig_desc, stub_desc = None, None # Don't raise an error if the stub is a coroutine, but the runtime isn't. # That results in false positives. # See https://github.com/python/typeshed/issues/7344 if runtime_is_coroutine and not stub.is_coroutine: yield Error( object_path, 'is an "async def" function at runtime, but not in the stub', stub, runtime, stub_desc=stub_desc, runtime_desc=runtime_sig_desc ) if not signature: return for message in _verify_signature(stub_sig, runtime_sig, function_name=stub.name): yield Error( object_path, "is inconsistent, " + message, stub, runtime, runtime_desc=runtime_sig_desc, ) @verify.register(Missing) def verify_none( stub: Missing, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: yield Error(object_path, "is not present in stub", stub, runtime) @verify.register(nodes.Var) def verify_var( stub: nodes.Var, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): # Don't always yield an error here, because we often can't find instance variables if len(object_path) <= 2: yield Error(object_path, "is not present at runtime", stub, runtime) return if ( stub.is_initialized_in_class and is_read_only_property(runtime) and (stub.is_settable_property or not stub.is_property) ): yield Error( object_path, "is read-only at runtime but not in the stub", stub, runtime ) runtime_type = get_mypy_type_of_runtime_value(runtime) if ( runtime_type is not None and stub.type is not None and not is_subtype_helper(runtime_type, stub.type) ): should_error = True # Avoid errors when defining enums, since runtime_type is the enum itself, but we'd # annotate it with the type of runtime.value if isinstance(runtime, enum.Enum): runtime_type = get_mypy_type_of_runtime_value(runtime.value) if runtime_type is not None and is_subtype_helper(runtime_type, stub.type): should_error = False if should_error: yield Error( object_path, f"variable differs from runtime type {runtime_type}", stub, runtime, ) @verify.register(nodes.OverloadedFuncDef) def verify_overloadedfuncdef( stub: nodes.OverloadedFuncDef, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): yield Error(object_path, "is not present at runtime", stub, runtime) return if stub.is_property: # Any property with a setter is represented as an OverloadedFuncDef if is_read_only_property(runtime): yield Error( object_path, "is read-only at runtime but not in the stub", stub, runtime ) return if not is_probably_a_function(runtime): yield Error(object_path, "is not a function", stub, runtime) if not callable(runtime): return for message in _verify_static_class_methods(stub, runtime, object_path): yield Error(object_path, "is inconsistent, " + message, stub, runtime) signature = safe_inspect_signature(runtime) if not signature: return stub_sig = Signature.from_overloadedfuncdef(stub) runtime_sig = Signature.from_inspect_signature(signature) for message in _verify_signature(stub_sig, runtime_sig, function_name=stub.name): # TODO: This is a little hacky, but the addition here is super useful if "has a default value of type" in message: message += ( ". This is often caused by overloads failing to account for explicitly passing " "in the default value." ) yield Error( object_path, "is inconsistent, " + message, stub, runtime, stub_desc=str(stub.type) + f"\nInferred signature: {stub_sig}", runtime_desc="def " + str(signature), ) @verify.register(nodes.TypeVarExpr) def verify_typevarexpr( stub: nodes.TypeVarExpr, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): # We seem to insert these typevars into NamedTuple stubs, but they # don't exist at runtime. Just ignore! if stub.name == "_NT": return yield Error(object_path, "is not present at runtime", stub, runtime) return if not isinstance(runtime, TypeVar): yield Error(object_path, "is not a TypeVar", stub, runtime) return @verify.register(nodes.ParamSpecExpr) def verify_paramspecexpr( stub: nodes.ParamSpecExpr, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): yield Error(object_path, "is not present at runtime", stub, runtime) return maybe_paramspec_types = ( getattr(typing, "ParamSpec", None), getattr(typing_extensions, "ParamSpec", None) ) paramspec_types = tuple([t for t in maybe_paramspec_types if t is not None]) if not paramspec_types or not isinstance(runtime, paramspec_types): yield Error(object_path, "is not a ParamSpec", stub, runtime) return def _verify_readonly_property(stub: nodes.Decorator, runtime: Any) -> Iterator[str]: assert stub.func.is_property if isinstance(runtime, property): return if inspect.isdatadescriptor(runtime): # It's enough like a property... return # Sometimes attributes pretend to be properties, for instance, to express that they # are read only. So allowlist if runtime_type matches the return type of stub. runtime_type = get_mypy_type_of_runtime_value(runtime) func_type = ( stub.func.type.ret_type if isinstance(stub.func.type, mypy.types.CallableType) else None ) if ( runtime_type is not None and func_type is not None and is_subtype_helper(runtime_type, func_type) ): return yield "is inconsistent, cannot reconcile @property on stub with runtime object" def _resolve_funcitem_from_decorator(dec: nodes.OverloadPart) -> Optional[nodes.FuncItem]: """Returns a FuncItem that corresponds to the output of the decorator. Returns None if we can't figure out what that would be. For convenience, this function also accepts FuncItems. """ if isinstance(dec, nodes.FuncItem): return dec if dec.func.is_property: return None def apply_decorator_to_funcitem( decorator: nodes.Expression, func: nodes.FuncItem ) -> Optional[nodes.FuncItem]: if not isinstance(decorator, nodes.RefExpr): return None if decorator.fullname is None: # Happens with namedtuple return None if decorator.fullname in ( "builtins.staticmethod", "abc.abstractmethod", ) or decorator.fullname in mypy.types.OVERLOAD_NAMES: return func if decorator.fullname == "builtins.classmethod": if func.arguments[0].variable.name not in ("cls", "mcs", "metacls"): raise StubtestFailure( f"unexpected class argument name {func.arguments[0].variable.name!r} " f"in {dec.fullname}" ) # FuncItem is written so that copy.copy() actually works, even when compiled ret = copy.copy(func) # Remove the cls argument, since it's not present in inspect.signature of classmethods ret.arguments = ret.arguments[1:] return ret # Just give up on any other decorators. After excluding properties, we don't run into # anything else when running on typeshed's stdlib. return None func: nodes.FuncItem = dec.func for decorator in dec.original_decorators: resulting_func = apply_decorator_to_funcitem(decorator, func) if resulting_func is None: return None func = resulting_func return func @verify.register(nodes.Decorator) def verify_decorator( stub: nodes.Decorator, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: if isinstance(runtime, Missing): yield Error(object_path, "is not present at runtime", stub, runtime) return if stub.func.is_property: for message in _verify_readonly_property(stub, runtime): yield Error(object_path, message, stub, runtime) return func = _resolve_funcitem_from_decorator(stub) if func is not None: yield from verify(func, runtime, object_path) @verify.register(nodes.TypeAlias) def verify_typealias( stub: nodes.TypeAlias, runtime: MaybeMissing[Any], object_path: List[str] ) -> Iterator[Error]: stub_target = mypy.types.get_proper_type(stub.target) if isinstance(runtime, Missing): yield Error( object_path, "is not present at runtime", stub, runtime, stub_desc=f"Type alias for: {stub_target}" ) return if isinstance(stub_target, mypy.types.Instance): yield from verify(stub_target.type, runtime, object_path) return if isinstance(stub_target, mypy.types.UnionType): if not getattr(runtime, "__origin__", None) is Union: yield Error(object_path, "is not a Union", stub, runtime, stub_desc=str(stub_target)) # could check Union contents here... return if isinstance(stub_target, mypy.types.TupleType): if tuple not in getattr(runtime, "__mro__", ()): yield Error( object_path, "is not a subclass of tuple", stub, runtime, stub_desc=str(stub_target) ) # could check Tuple contents here... return if isinstance(stub_target, mypy.types.AnyType): return yield Error( object_path, "is not a recognised type alias", stub, runtime, stub_desc=str(stub_target) ) # ==================== # Helpers # ==================== IGNORED_MODULE_DUNDERS = frozenset( { "__file__", "__doc__", "__name__", "__builtins__", "__package__", "__cached__", "__loader__", "__spec__", "__annotations__", "__path__", # mypy adds __path__ to packages, but C packages don't have it "__getattr__", # resulting behaviour might be typed explicitly # TODO: remove the following from this list "__author__", "__version__", "__copyright__", } ) IGNORABLE_CLASS_DUNDERS = frozenset( { # Special attributes "__dict__", "__text_signature__", "__weakref__", "__del__", # Only ever called when an object is being deleted, who cares? "__hash__", "__getattr__", # resulting behaviour might be typed explicitly "__setattr__", # defining this on a class can cause worse type checking # isinstance/issubclass hooks that type-checkers don't usually care about "__instancecheck__", "__subclasshook__", "__subclasscheck__", # Pickle methods "__setstate__", "__getstate__", "__getnewargs__", "__getinitargs__", "__reduce_ex__", "__reduce__", # ctypes weirdness "__ctype_be__", "__ctype_le__", "__ctypes_from_outparam__", # mypy limitations "__abstractmethods__", # Classes with metaclass=ABCMeta inherit this attribute "__new_member__", # If an enum defines __new__, the method is renamed as __new_member__ "__dataclass_fields__", # Generated by dataclasses "__dataclass_params__", # Generated by dataclasses "__doc__", # mypy's semanal for namedtuples assumes this is str, not Optional[str] # typing implementation details, consider removing some of these: "__parameters__", "__origin__", "__args__", "__orig_bases__", "__final__", # Consider removing __slots__? "__slots__", } ) def is_probably_private(name: str) -> bool: return name.startswith("_") and not is_dunder(name) def is_probably_a_function(runtime: Any) -> bool: return ( isinstance(runtime, (types.FunctionType, types.BuiltinFunctionType)) or isinstance(runtime, (types.MethodType, types.BuiltinMethodType)) or (inspect.ismethoddescriptor(runtime) and callable(runtime)) ) def is_read_only_property(runtime: object) -> bool: return isinstance(runtime, property) and runtime.fset is None def safe_inspect_signature(runtime: Any) -> Optional[inspect.Signature]: try: return inspect.signature(runtime) except Exception: # inspect.signature throws ValueError all the time # catch RuntimeError because of https://bugs.python.org/issue39504 # catch TypeError because of https://github.com/python/typeshed/pull/5762 # catch AttributeError because of inspect.signature(_curses.window.border) return None def is_subtype_helper(left: mypy.types.Type, right: mypy.types.Type) -> bool: """Checks whether ``left`` is a subtype of ``right``.""" left = mypy.types.get_proper_type(left) right = mypy.types.get_proper_type(right) if ( isinstance(left, mypy.types.LiteralType) and isinstance(left.value, int) and left.value in (0, 1) and isinstance(right, mypy.types.Instance) and right.type.fullname == "builtins.bool" ): # Pretend Literal[0, 1] is a subtype of bool to avoid unhelpful errors. return True if ( isinstance(right, mypy.types.TypedDictType) and isinstance(left, mypy.types.Instance) and left.type.fullname == "builtins.dict" ): # Special case checks against TypedDicts return True with mypy.state.state.strict_optional_set(True): return mypy.subtypes.is_subtype(left, right) def get_mypy_type_of_runtime_value(runtime: Any) -> Optional[mypy.types.Type]: """Returns a mypy type object representing the type of ``runtime``. Returns None if we can't find something that works. """ if runtime is None: return mypy.types.NoneType() if isinstance(runtime, property): # Give up on properties to avoid issues with things that are typed as attributes. return None def anytype() -> mypy.types.AnyType: return mypy.types.AnyType(mypy.types.TypeOfAny.unannotated) if isinstance( runtime, (types.FunctionType, types.BuiltinFunctionType, types.MethodType, types.BuiltinMethodType) ): builtins = get_stub("builtins") assert builtins is not None type_info = builtins.names["function"].node assert isinstance(type_info, nodes.TypeInfo) fallback = mypy.types.Instance(type_info, [anytype()]) signature = safe_inspect_signature(runtime) if signature: arg_types = [] arg_kinds = [] arg_names = [] for arg in signature.parameters.values(): arg_types.append(anytype()) arg_names.append( None if arg.kind == inspect.Parameter.POSITIONAL_ONLY else arg.name ) has_default = arg.default == inspect.Parameter.empty if arg.kind == inspect.Parameter.POSITIONAL_ONLY: arg_kinds.append(nodes.ARG_POS if has_default else nodes.ARG_OPT) elif arg.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD: arg_kinds.append(nodes.ARG_POS if has_default else nodes.ARG_OPT) elif arg.kind == inspect.Parameter.KEYWORD_ONLY: arg_kinds.append(nodes.ARG_NAMED if has_default else nodes.ARG_NAMED_OPT) elif arg.kind == inspect.Parameter.VAR_POSITIONAL: arg_kinds.append(nodes.ARG_STAR) elif arg.kind == inspect.Parameter.VAR_KEYWORD: arg_kinds.append(nodes.ARG_STAR2) else: raise AssertionError else: arg_types = [anytype(), anytype()] arg_kinds = [nodes.ARG_STAR, nodes.ARG_STAR2] arg_names = [None, None] return mypy.types.CallableType( arg_types, arg_kinds, arg_names, ret_type=anytype(), fallback=fallback, is_ellipsis_args=True, ) # Try and look up a stub for the runtime object stub = get_stub(type(runtime).__module__) if stub is None: return None type_name = type(runtime).__name__ if type_name not in stub.names: return None type_info = stub.names[type_name].node if isinstance(type_info, nodes.Var): return type_info.type if not isinstance(type_info, nodes.TypeInfo): return None if isinstance(runtime, tuple): # Special case tuples so we construct a valid mypy.types.TupleType optional_items = [get_mypy_type_of_runtime_value(v) for v in runtime] items = [(i if i is not None else anytype()) for i in optional_items] fallback = mypy.types.Instance(type_info, [anytype()]) return mypy.types.TupleType(items, fallback) fallback = mypy.types.Instance(type_info, [anytype() for _ in type_info.type_vars]) value: Union[bool, int, str] if isinstance(runtime, bytes): value = bytes_to_human_readable_repr(runtime) elif isinstance(runtime, enum.Enum): value = runtime.name elif isinstance(runtime, (bool, int, str)): value = runtime else: return fallback return mypy.types.LiteralType(value=value, fallback=fallback) # ==================== # Build and entrypoint # ==================== _all_stubs: Dict[str, nodes.MypyFile] = {} def build_stubs(modules: List[str], options: Options, find_submodules: bool = False) -> List[str]: """Uses mypy to construct stub objects for the given modules. This sets global state that ``get_stub`` can access. Returns all modules we might want to check. If ``find_submodules`` is False, this is equal to ``modules``. :param modules: List of modules to build stubs for. :param options: Mypy options for finding and building stubs. :param find_submodules: Whether to attempt to find submodules of the given modules as well. """ data_dir = mypy.build.default_data_dir() search_path = mypy.modulefinder.compute_search_paths([], options, data_dir) find_module_cache = mypy.modulefinder.FindModuleCache( search_path, fscache=None, options=options ) all_modules = [] sources = [] for module in modules: all_modules.append(module) if not find_submodules: module_path = find_module_cache.find_module(module) if not isinstance(module_path, str): # test_module will yield an error later when it can't find stubs continue sources.append(mypy.modulefinder.BuildSource(module_path, module, None)) else: found_sources = find_module_cache.find_modules_recursive(module) sources.extend(found_sources) # find submodules via mypy all_modules.extend(s.module for s in found_sources if s.module not in all_modules) # find submodules via pkgutil try: runtime = silent_import_module(module) all_modules.extend( m.name for m in pkgutil.walk_packages(runtime.__path__, runtime.__name__ + ".") if m.name not in all_modules ) except Exception: pass if sources: try: res = mypy.build.build(sources=sources, options=options) except mypy.errors.CompileError as e: raise StubtestFailure(f"failed mypy compile:\n{e}") from e if res.errors: raise StubtestFailure("mypy build errors:\n" + "\n".join(res.errors)) global _all_stubs _all_stubs = res.files return all_modules def get_stub(module: str) -> Optional[nodes.MypyFile]: """Returns a stub object for the given module, if we've built one.""" return _all_stubs.get(module) def get_typeshed_stdlib_modules( custom_typeshed_dir: Optional[str], version_info: Optional[Tuple[int, int]] = None ) -> List[str]: """Returns a list of stdlib modules in typeshed (for current Python version).""" stdlib_py_versions = mypy.modulefinder.load_stdlib_py_versions(custom_typeshed_dir) if version_info is None: version_info = sys.version_info[0:2] # Typeshed's minimum supported Python 3 is Python 3.6 if sys.version_info < (3, 6): version_info = (3, 6) def exists_in_version(module: str) -> bool: assert version_info is not None parts = module.split(".") for i in range(len(parts), 0, -1): current_module = ".".join(parts[:i]) if current_module in stdlib_py_versions: minver, maxver = stdlib_py_versions[current_module] return version_info >= minver and (maxver is None or version_info <= maxver) return False if custom_typeshed_dir: typeshed_dir = Path(custom_typeshed_dir) else: typeshed_dir = Path(mypy.build.default_data_dir()) / "typeshed" stdlib_dir = typeshed_dir / "stdlib" modules = [] for path in stdlib_dir.rglob("*.pyi"): if path.stem == "__init__": path = path.parent module = ".".join(path.relative_to(stdlib_dir).parts[:-1] + (path.stem,)) if exists_in_version(module): modules.append(module) return sorted(modules) def get_allowlist_entries(allowlist_file: str) -> Iterator[str]: def strip_comments(s: str) -> str: try: return s[: s.index("#")].strip() except ValueError: return s.strip() with open(allowlist_file) as f: for line in f.readlines(): entry = strip_comments(line) if entry: yield entry class _Arguments: modules: List[str] concise: bool ignore_missing_stub: bool ignore_positional_only: bool allowlist: List[str] generate_allowlist: bool ignore_unused_allowlist: bool mypy_config_file: str custom_typeshed_dir: str check_typeshed: bool version: str def test_stubs(args: _Arguments, use_builtins_fixtures: bool = False) -> int: """This is stubtest! It's time to test the stubs!""" # Load the allowlist. This is a series of strings corresponding to Error.object_desc # Values in the dict will store whether we used the allowlist entry or not. allowlist = { entry: False for allowlist_file in args.allowlist for entry in get_allowlist_entries(allowlist_file) } allowlist_regexes = {entry: re.compile(entry) for entry in allowlist} # If we need to generate an allowlist, we store Error.object_desc for each error here. generated_allowlist = set() modules = args.modules if args.check_typeshed: if args.modules: print( _style("error:", color="red", bold=True), "cannot pass both --check-typeshed and a list of modules", ) return 1 modules = get_typeshed_stdlib_modules(args.custom_typeshed_dir) # typeshed added a stub for __main__, but that causes stubtest to check itself annoying_modules = {"antigravity", "this", "__main__"} modules = [m for m in modules if m not in annoying_modules] if not modules: print( _style("error:", color="red", bold=True), "no modules to check", ) return 1 options = Options() options.incremental = False options.custom_typeshed_dir = args.custom_typeshed_dir options.config_file = args.mypy_config_file options.use_builtins_fixtures = use_builtins_fixtures if options.config_file: def set_strict_flags() -> None: # not needed yet return parse_config_file(options, set_strict_flags, options.config_file, sys.stdout, sys.stderr) try: modules = build_stubs(modules, options, find_submodules=not args.check_typeshed) except StubtestFailure as stubtest_failure: print( _style("error:", color="red", bold=True), f"not checking stubs due to {stubtest_failure}", ) return 1 exit_code = 0 error_count = 0 for module in modules: for error in test_module(module): # Filter errors if args.ignore_missing_stub and error.is_missing_stub(): continue if args.ignore_positional_only and error.is_positional_only_related(): continue if error.object_desc in allowlist: allowlist[error.object_desc] = True continue is_allowlisted = False for w in allowlist: if allowlist_regexes[w].fullmatch(error.object_desc): allowlist[w] = True is_allowlisted = True break if is_allowlisted: continue # We have errors, so change exit code, and output whatever necessary exit_code = 1 if args.generate_allowlist: generated_allowlist.add(error.object_desc) continue print(error.get_description(concise=args.concise)) error_count += 1 # Print unused allowlist entries if not args.ignore_unused_allowlist: for w in allowlist: # Don't consider an entry unused if it regex-matches the empty string # This lets us allowlist errors that don't manifest at all on some systems if not allowlist[w] and not allowlist_regexes[w].fullmatch(""): exit_code = 1 error_count += 1 print(f"note: unused allowlist entry {w}") # Print the generated allowlist if args.generate_allowlist: for e in sorted(generated_allowlist): print(e) exit_code = 0 elif not args.concise: if error_count: print( _style( f"Found {error_count} error{plural_s(error_count)}" f" (checked {len(modules)} module{plural_s(modules)})", color="red", bold=True ) ) else: print( _style( f"Success: no issues found in {len(modules)} module{plural_s(modules)}", color="green", bold=True ) ) return exit_code def parse_options(args: List[str]) -> _Arguments: parser = argparse.ArgumentParser( description="Compares stubs to objects introspected from the runtime." ) parser.add_argument("modules", nargs="*", help="Modules to test") parser.add_argument( "--concise", action="store_true", help="Makes stubtest's output more concise, one line per error", ) parser.add_argument( "--ignore-missing-stub", action="store_true", help="Ignore errors for stub missing things that are present at runtime", ) parser.add_argument( "--ignore-positional-only", action="store_true", help="Ignore errors for whether an argument should or shouldn't be positional-only", ) parser.add_argument( "--allowlist", "--whitelist", action="append", metavar="FILE", default=[], help=( "Use file as an allowlist. Can be passed multiple times to combine multiple " "allowlists. Allowlists can be created with --generate-allowlist. Allowlists " "support regular expressions." ), ) parser.add_argument( "--generate-allowlist", "--generate-whitelist", action="store_true", help="Print an allowlist (to stdout) to be used with --allowlist", ) parser.add_argument( "--ignore-unused-allowlist", "--ignore-unused-whitelist", action="store_true", help="Ignore unused allowlist entries", ) parser.add_argument( "--mypy-config-file", metavar="FILE", help=( "Use specified mypy config file to determine mypy plugins " "and mypy path" ), ) parser.add_argument( "--custom-typeshed-dir", metavar="DIR", help="Use the custom typeshed in DIR" ) parser.add_argument( "--check-typeshed", action="store_true", help="Check all stdlib modules in typeshed" ) parser.add_argument( "--version", action="version", version="%(prog)s " + mypy.version.__version__ ) return parser.parse_args(args, namespace=_Arguments()) def main() -> int: mypy.util.check_python_version("stubtest") return test_stubs(parse_options(sys.argv[1:])) if __name__ == "__main__": sys.exit(main())