refactor: unify slash/prefix command signature evaluation (#1116)

changelog/1116.misc.rst

@@ -0,0 +1 @@
+|commands| Rewrite slash command signature evaluation to use the same mechanism as prefix command signatures. This should not have an impact on user code, but streamlines future changes.

disnake/ext/commands/core.py

@@ -27,7 +27,12 @@
 )
 
 import disnake
-from disnake.utils import _generated, _overload_with_permissions
+from disnake.utils import (
+    _generated,
+    _overload_with_permissions,
+    get_signature_parameters,
+    unwrap_function,
+)
 
 from ._types import _BaseCommand
 from .cog import Cog
@@ -114,42 +119,6 @@
     P = TypeVar("P")
 
 
-def unwrap_function(function: Callable[..., Any]) -> Callable[..., Any]:
-    partial = functools.partial
-    while True:
-        if hasattr(function, "__wrapped__"):
-            function = function.__wrapped__
-        elif isinstance(function, partial):
-            function = function.func
-        else:
-            return function
-
-
-def get_signature_parameters(
-    function: Callable[..., Any], globalns: Dict[str, Any]
-) -> Dict[str, inspect.Parameter]:
-    signature = inspect.signature(function)
-    params = {}
-    cache: Dict[str, Any] = {}
-    eval_annotation = disnake.utils.evaluate_annotation
-    for name, parameter in signature.parameters.items():
-        annotation = parameter.annotation
-        if annotation is parameter.empty:
-            params[name] = parameter
-            continue
-        if annotation is None:
-            params[name] = parameter.replace(annotation=type(None))
-            continue
-
-        annotation = eval_annotation(annotation, globalns, globalns, cache)
-        if annotation is Greedy:
-            raise TypeError("Unparameterized Greedy[...] is disallowed in signature.")
-
-        params[name] = parameter.replace(annotation=annotation)
-
-    return params
-
-
 def wrap_callback(coro):
     @functools.wraps(coro)
     async def wrapped(*args, **kwargs):
@@ -410,7 +379,11 @@ def callback(self, function: CommandCallback[CogT, Any, P, T]) -> None:
         except AttributeError:
             globalns = {}
 
-        self.params = get_signature_parameters(function, globalns)
+        params = get_signature_parameters(function, globalns)
+        for param in params.values():
+            if param.annotation is Greedy:
+                raise TypeError("Unparameterized Greedy[...] is disallowed in signature.")
+        self.params = params
 
     def add_check(self, func: Check) -> None:
         """Adds a check to the command.

disnake/ext/commands/params.py

@@ -10,6 +10,7 @@
 import itertools
 import math
 import sys
+import types
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from enum import Enum, EnumMeta
@@ -32,7 +33,6 @@
     TypeVar,
     Union,
     get_origin,
-    get_type_hints,
 )
 
 import disnake
@@ -42,7 +42,7 @@
 from disnake.ext import commands
 from disnake.i18n import Localized
 from disnake.interactions import ApplicationCommandInteraction
-from disnake.utils import maybe_coroutine
+from disnake.utils import get_signature_parameters, get_signature_return, maybe_coroutine
 
 from . import errors
 from .converter import CONVERTER_MAPPING
@@ -143,37 +143,6 @@ def remove_optionals(annotation: Any) -> Any:
     return annotation
 
 
-def signature(func: Callable) -> inspect.Signature:
-    """Get the signature with evaluated annotations wherever possible
-
-    This is equivalent to `signature(..., eval_str=True)` in python 3.10
-    """
-    if sys.version_info >= (3, 10):
-        return inspect.signature(func, eval_str=True)
-
-    if inspect.isfunction(func) or inspect.ismethod(func):
-        typehints = get_type_hints(func)
-    else:
-        typehints = get_type_hints(func.__call__)
-
-    signature = inspect.signature(func)
-    parameters = []
-
-    for name, param in signature.parameters.items():
-        if isinstance(param.annotation, str):
-            param = param.replace(annotation=typehints.get(name, inspect.Parameter.empty))
-        if param.annotation is type(None):
-            param = param.replace(annotation=None)
-
-        parameters.append(param)
-
-    return_annotation = typehints.get("return", inspect.Parameter.empty)
-    if return_annotation is type(None):
-        return_annotation = None
-
-    return signature.replace(parameters=parameters, return_annotation=return_annotation)
-
-
 def _xt_to_xe(xe: Optional[float], xt: Optional[float], direction: float = 1) -> Optional[float]:
     """Function for combining xt and xe
 
@@ -795,7 +764,14 @@ def parse_annotation(self, annotation: Any, converter_mode: bool = False) -> boo
         return True
 
     def parse_converter_annotation(self, converter: Callable, fallback_annotation: Any) -> None:
-        _, parameters = isolate_self(signature(converter))
+        if isinstance(converter, (types.FunctionType, types.MethodType)):
+            converter_func = converter
+        else:
+            # if converter isn't a function/method, assume it's a callable object/type
+            # (we need `__call__` here to get the correct global namespace later, since
+            # classes do not have `__globals__`)
+            converter_func = converter.__call__
+        _, parameters = isolate_self(get_signature_parameters(converter_func))
 
         if len(parameters) != 1:
             raise TypeError(
@@ -858,9 +834,9 @@ def to_option(self) -> Option:
 def safe_call(function: Callable[..., T], /, *possible_args: Any, **possible_kwargs: Any) -> T:
     """Calls a function without providing any extra unexpected arguments"""
     MISSING: Any = object()
-    sig = signature(function)
+    parameters = get_signature_parameters(function)
 
-    kinds = {p.kind for p in sig.parameters.values()}
+    kinds = {p.kind for p in parameters.values()}
     arb = {inspect.Parameter.VAR_POSITIONAL, inspect.Parameter.VAR_KEYWORD}
     if arb.issubset(kinds):
         raise TypeError(
@@ -874,7 +850,7 @@ def safe_call(function: Callable[..., T], /, *possible_args: Any, **possible_kwa
 
     for index, parameter, posarg in itertools.zip_longest(
         itertools.count(),
-        sig.parameters.values(),
+        parameters.values(),
         possible_args,
         fillvalue=MISSING,
     ):
@@ -903,15 +879,15 @@ def safe_call(function: Callable[..., T], /, *possible_args: Any, **possible_kwa
 
 
 def isolate_self(
-    sig: inspect.Signature,
+    parameters: Dict[str, inspect.Parameter],
 ) -> Tuple[Tuple[Optional[inspect.Parameter], ...], Dict[str, inspect.Parameter]]:
     """Create parameters without self and the first interaction"""
-    parameters = dict(sig.parameters)
-    parametersl = list(sig.parameters.values())
-
     if not parameters:
         return (None, None), {}
 
+    parameters = dict(parameters)  # shallow copy
+    parametersl = list(parameters.values())
+
     cog_param: Optional[inspect.Parameter] = None
     inter_param: Optional[inspect.Parameter] = None
 
@@ -961,19 +937,19 @@ def classify_autocompleter(autocompleter: AnyAutocompleter) -> None:
 
 def collect_params(
     function: Callable,
-    sig: Optional[inspect.Signature] = None,
+    parameters: Optional[Dict[str, inspect.Parameter]] = None,
 ) -> Tuple[Optional[str], Optional[str], List[ParamInfo], Dict[str, Injection]]:
     """Collect all parameters in a function.
 
-    Optionally accepts an `inspect.Signature` object (as an optimization),
-    calls `signature(function)` if not provided.
+    Optionally accepts a `{str: inspect.Parameter}` dict as an optimization,
+    calls `get_signature_parameters(function)` if not provided.
 
     Returns: (`cog parameter`, `interaction parameter`, `param infos`, `injections`)
     """
-    if sig is None:
-        sig = signature(function)
+    if parameters is None:
+        parameters = get_signature_parameters(function)
 
-    (cog_param, inter_param), parameters = isolate_self(sig)
+    (cog_param, inter_param), parameters = isolate_self(parameters)
 
     doc = disnake.utils.parse_docstring(function)["params"]
 
@@ -1097,10 +1073,10 @@ def expand_params(command: AnySlashCommand) -> List[Option]:
 
     Returns the created options
     """
-    sig = signature(command.callback)
-    # pass `sig` down to avoid having to call `signature(func)` another time,
+    parameters = get_signature_parameters(command.callback)
+    # pass `parameters` down to avoid having to call `get_signature_parameters(func)` another time,
     # which may cause side effects with deferred annotations and warnings
-    _, inter_param, params, injections = collect_params(command.callback, sig)
+    _, inter_param, params, injections = collect_params(command.callback, parameters)
 
     if inter_param is None:
         raise TypeError(f"Couldn't find an interaction parameter in {command.callback}")
@@ -1125,7 +1101,7 @@ def expand_params(command: AnySlashCommand) -> List[Option]:
         if param.autocomplete:
             command.autocompleters[param.name] = param.autocomplete
 
-    if issubclass_(sig.parameters[inter_param].annotation, disnake.GuildCommandInteraction):
+    if issubclass_(parameters[inter_param].annotation, disnake.GuildCommandInteraction):
         command._guild_only = True
 
     return [param.to_option() for param in params]
@@ -1407,12 +1383,11 @@ def register_injection(
     :class:`Injection`
         The injection being registered.
     """
-    sig = signature(function)
-    tp = sig.return_annotation
+    tp = get_signature_return(function)
 
     if tp is inspect.Parameter.empty:
         raise TypeError("Injection must have a return annotation")
     if tp in ParamInfo.TYPES:
         raise TypeError("Injection cannot overwrite builtin types")
 
-    return Injection.register(function, sig.return_annotation, autocompleters=autocompleters)
+    return Injection.register(function, tp, autocompleters=autocompleters)

disnake/utils.py

@@ -6,6 +6,7 @@
 import asyncio
 import datetime
 import functools
+import inspect
 import json
 import os
 import pkgutil
@@ -1203,6 +1204,72 @@ def resolve_annotation(
     return evaluate_annotation(annotation, globalns, locals, cache)
 
 
+def unwrap_function(function: Callable[..., Any]) -> Callable[..., Any]:
+    partial = functools.partial
+    while True:
+        if hasattr(function, "__wrapped__"):
+            function = function.__wrapped__
+        elif isinstance(function, partial):
+            function = function.func
+        else:
+            return function
+
+
+def _get_function_globals(function: Callable[..., Any]) -> Dict[str, Any]:
+    unwrap = unwrap_function(function)
+    try:
+        return unwrap.__globals__
+    except AttributeError:
+        return {}
+
+
+_inspect_empty = inspect.Parameter.empty
+
+
+def get_signature_parameters(
+    function: Callable[..., Any], globalns: Optional[Dict[str, Any]] = None
+) -> Dict[str, inspect.Parameter]:
+    # if no globalns provided, unwrap (where needed) and get global namespace from there
+    if globalns is None:
+        globalns = _get_function_globals(function)
+
+    params: Dict[str, inspect.Parameter] = {}
+    cache: Dict[str, Any] = {}
+
+    signature = inspect.signature(function)
+
+    # eval all parameter annotations
+    for name, parameter in signature.parameters.items():
+        annotation = parameter.annotation
+        if annotation is _inspect_empty:
+            params[name] = parameter
+            continue
+
+        if annotation is None:
+            annotation = type(None)
+        else:
+            annotation = evaluate_annotation(annotation, globalns, globalns, cache)
+
+        params[name] = parameter.replace(annotation=annotation)
+
+    return params
+
+
+def get_signature_return(function: Callable[..., Any]) -> Any:
+    signature = inspect.signature(function)
+
+    # same as parameters above, but for the return annotation
+    ret = signature.return_annotation
+    if ret is not _inspect_empty:
+        if ret is None:
+            ret = type(None)
+        else:
+            globalns = _get_function_globals(function)
+            ret = evaluate_annotation(ret, globalns, globalns, {})
+
+    return ret
+
+
 TimestampStyle = Literal["f", "F", "d", "D", "t", "T", "R"]
 
 

tests/ext/commands/test_params.py

@@ -71,7 +71,7 @@ def test_isolate_self(self) -> None:
         def func(a: int) -> None:
             ...
 
-        (cog, inter), parameters = params.isolate_self(params.signature(func))
+        (cog, inter), parameters = params.isolate_self(params.get_signature_parameters(func))
         assert cog is None
         assert inter is None
         assert parameters == ({"a": mock.ANY})
@@ -80,7 +80,7 @@ def test_isolate_self_inter(self) -> None:
         def func(i: disnake.ApplicationCommandInteraction, a: int) -> None:
             ...
 
-        (cog, inter), parameters = params.isolate_self(params.signature(func))
+        (cog, inter), parameters = params.isolate_self(params.get_signature_parameters(func))
         assert cog is None
         assert inter is not None
         assert parameters == ({"a": mock.ANY})
@@ -89,7 +89,7 @@ def test_isolate_self_cog_inter(self) -> None:
         def func(self, i: disnake.ApplicationCommandInteraction, a: int) -> None:
             ...
 
-        (cog, inter), parameters = params.isolate_self(params.signature(func))
+        (cog, inter), parameters = params.isolate_self(params.get_signature_parameters(func))
         assert cog is not None
         assert inter is not None
         assert parameters == ({"a": mock.ANY})
@@ -98,7 +98,7 @@ def test_isolate_self_generic(self) -> None:
         def func(i: disnake.ApplicationCommandInteraction[commands.Bot], a: int) -> None:
             ...
 
-        (cog, inter), parameters = params.isolate_self(params.signature(func))
+        (cog, inter), parameters = params.isolate_self(params.get_signature_parameters(func))
         assert cog is None
         assert inter is not None
         assert parameters == ({"a": mock.ANY})
@@ -109,7 +109,7 @@ def func(
         ) -> None:
             ...
 
-        (cog, inter), parameters = params.isolate_self(params.signature(func))
+        (cog, inter), parameters = params.isolate_self(params.get_signature_parameters(func))
         assert cog is None
         assert inter is not None
         assert parameters == ({"a": mock.ANY})