Root validator signature (#5294)

* Fix type hints for root_validator

* Add mypy test

* Fix mypy test

pydantic/decorators.py

@@ -221,7 +221,7 @@ def root_validator(
     *,
     # if you don't specify `pre` the default is `pre=False`
     # which means you need to specify `skip_on_failure=True`
-    skip_on_failure: Literal[True] = ...,
+    skip_on_failure: Literal[True],
     allow_reuse: bool = ...,
 ) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType,]:
     ...
@@ -230,11 +230,9 @@ def root_validator(
 @overload
 def root_validator(
     *,
-    # for pre=False you don't need to specify `skip_on_failure`
     # if you specify `pre=True` then you don't need to specify
     # `skip_on_failure`, in fact it is not allowed as an argument!
     pre: Literal[True],
-    skip_on_failure: Literal[True],
     allow_reuse: bool = ...,
 ) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType,]:
     ...
@@ -246,7 +244,7 @@ def root_validator(
     # if you explicitly specify `pre=False` then you
     # MUST specify `skip_on_failure=True`
     pre: Literal[False],
-    skip_on_failure: Literal[True] = ...,
+    skip_on_failure: Literal[True],
     allow_reuse: bool = ...,
 ) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType,]:
     ...

tests/mypy/modules/fail4.py

@@ -1,4 +1,6 @@
-from pydantic import validate_arguments
+from typing import Any
+
+from pydantic import BaseModel, root_validator, validate_arguments
 
 
 @validate_arguments
@@ -24,3 +26,21 @@ def bar() -> str:
 
 # return type should be a string
 y: int = bar()
+
+
+# Demonstrate type errors for root_validator signatures
+class Model(BaseModel):
+    @root_validator()
+    @classmethod
+    def validate_1(cls, values: Any) -> Any:
+        return values
+
+    @root_validator(pre=True, skip_on_failure=True)
+    @classmethod
+    def validate_2(cls, values: Any) -> Any:
+        return values
+
+    @root_validator(pre=False)
+    @classmethod
+    def validate_3(cls, values: Any) -> Any:
+        return values

tests/mypy/modules/success.py

@@ -70,7 +70,7 @@ def check_age(cls, value: int) -> int:
     def root_check(cls, values: Dict[str, Any]) -> Dict[str, Any]:
         return values
 
-    @root_validator(pre=True, skip_on_failure=True, allow_reuse=False)
+    @root_validator(pre=True, allow_reuse=False)
     def pre_root_check(cls, values: Dict[str, Any]) -> Dict[str, Any]:
         return values
 

tests/mypy/outputs/latest/fail4.txt

@@ -1,8 +1,23 @@
-5: note: "foo" defined here
-12: error: Argument 1 to "foo" has incompatible type "str"; expected "int"  [arg-type]
-13: error: Argument "c" to "foo" has incompatible type "int"; expected "str"  [arg-type]
-14: error: Too many positional arguments for "foo"  [misc]
-14: error: Argument 2 to "foo" has incompatible type "int"; expected "str"  [arg-type]
-15: error: Unexpected keyword argument "d" for "foo"  [call-arg]
-17: error: "Callable[[int, DefaultNamedArg(str, 'c')], str]" has no attribute "raw_function"  [attr-defined]
-26: error: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
+7: note: "foo" defined here
+14: error: Argument 1 to "foo" has incompatible type "str"; expected "int"  [arg-type]
+15: error: Argument "c" to "foo" has incompatible type "int"; expected "str"  [arg-type]
+16: error: Too many positional arguments for "foo"  [misc]
+16: error: Argument 2 to "foo" has incompatible type "int"; expected "str"  [arg-type]
+17: error: Unexpected keyword argument "d" for "foo"  [call-arg]
+19: error: "Callable[[int, DefaultNamedArg(str, 'c')], str]" has no attribute "raw_function"  [attr-defined]
+28: error: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
+33: error: All overload variants of "root_validator" require at least one argument  [call-overload]
+33: note: Possible overload variants:
+33: note:     def root_validator(*, skip_on_failure: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+33: note:     def root_validator(*, pre: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+33: note:     def root_validator(*, pre: Literal[False], skip_on_failure: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+38: error: No overload variant of "root_validator" matches argument types "bool", "bool"  [call-overload]
+38: note: Possible overload variants:
+38: note:     def root_validator(*, skip_on_failure: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+38: note:     def root_validator(*, pre: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+38: note:     def root_validator(*, pre: Literal[False], skip_on_failure: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+43: error: No overload variant of "root_validator" matches argument type "bool"  [call-overload]
+43: note: Possible overload variants:
+43: note:     def root_validator(*, skip_on_failure: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+43: note:     def root_validator(*, pre: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]
+43: note:     def root_validator(*, pre: Literal[False], skip_on_failure: Literal[True], allow_reuse: bool = ...) -> Callable[[_V1RootValidatorFunctionType], _V1RootValidatorFunctionType]