From 79b1c8d6a467cd829bf6b9e3919fbcef7b50eb19 Mon Sep 17 00:00:00 2001 From: Ivan Levkivskyi Date: Sun, 23 Jun 2024 15:12:41 +0100 Subject: [PATCH] Fix previous partial fix (#17429) This is a bit unfortunate, but the best we can probably do. cc @hauntsaninja --- mypy/plugins/functools.py | 34 ++++++++++++++++++++++------- test-data/unit/check-functools.test | 13 +++++++++++ 2 files changed, 39 insertions(+), 8 deletions(-) diff --git a/mypy/plugins/functools.py b/mypy/plugins/functools.py index e41afe2fde02..19be71ca36df 100644 --- a/mypy/plugins/functools.py +++ b/mypy/plugins/functools.py @@ -137,6 +137,20 @@ def partial_new_callback(ctx: mypy.plugin.FunctionContext) -> Type: # We must normalize from the start to have coherent view together with TypeChecker. fn_type = fn_type.with_unpacked_kwargs().with_normalized_var_args() + last_context = ctx.api.type_context[-1] + if not fn_type.is_type_obj(): + # We wrap the return type to get use of a possible type context provided by caller. + # We cannot do this in case of class objects, since otherwise the plugin may get + # falsely triggered when evaluating the constructed call itself. + ret_type: Type = ctx.api.named_generic_type(PARTIAL, [fn_type.ret_type]) + wrapped_return = True + else: + ret_type = fn_type.ret_type + # Instead, for class objects we ignore any type context to avoid spurious errors, + # since the type context will be partial[X] etc., not X. + ctx.api.type_context[-1] = None + wrapped_return = False + defaulted = fn_type.copy_modified( arg_kinds=[ ( @@ -146,7 +160,7 @@ def partial_new_callback(ctx: mypy.plugin.FunctionContext) -> Type: ) for k in fn_type.arg_kinds ], - ret_type=ctx.api.named_generic_type(PARTIAL, [fn_type.ret_type]), + ret_type=ret_type, ) if defaulted.line < 0: # Make up a line number if we don't have one @@ -189,16 +203,20 @@ def partial_new_callback(ctx: mypy.plugin.FunctionContext) -> Type: arg_names=actual_arg_names, context=call_expr, ) + if not wrapped_return: + # Restore previously ignored context. + ctx.api.type_context[-1] = last_context + bound = get_proper_type(bound) if not isinstance(bound, CallableType): return ctx.default_return_type - wrapped_ret_type = get_proper_type(bound.ret_type) - if not isinstance(wrapped_ret_type, Instance) or wrapped_ret_type.type.fullname != PARTIAL: - return ctx.default_return_type - if not mypy.semanal.refers_to_fullname(ctx.args[0][0], PARTIAL): - # If the first argument is partial, above call will trigger the plugin - # again, in between the wrapping above an unwrapping here. - bound = bound.copy_modified(ret_type=wrapped_ret_type.args[0]) + + if wrapped_return: + # Reverse the wrapping we did above. + ret_type = get_proper_type(bound.ret_type) + if not isinstance(ret_type, Instance) or ret_type.type.fullname != PARTIAL: + return ctx.default_return_type + bound = bound.copy_modified(ret_type=ret_type.args[0]) formal_to_actual = map_actuals_to_formals( actual_kinds=actual_arg_kinds, diff --git a/test-data/unit/check-functools.test b/test-data/unit/check-functools.test index 997f5bc70c7d..e4b3e4cffdc1 100644 --- a/test-data/unit/check-functools.test +++ b/test-data/unit/check-functools.test @@ -455,3 +455,16 @@ first_kw([1]) # E: Too many positional arguments for "get" \ # E: Too few arguments for "get" \ # E: Argument 1 to "get" has incompatible type "List[int]"; expected "int" [builtins fixtures/list.pyi] + +[case testFunctoolsPartialClassObjectMatchingPartial] +from functools import partial + +class A: + def __init__(self, var: int, b: int, c: int) -> None: ... + +p = partial(A, 1) +reveal_type(p) # N: Revealed type is "functools.partial[__main__.A]" +p(1, "no") # E: Argument 2 to "A" has incompatible type "str"; expected "int" + +q: partial[A] = partial(A, 1) # OK +[builtins fixtures/tuple.pyi]