mirror of
https://github.com/microsoft/pyright.git
synced 2024-09-11 07:55:56 +03:00
Added support for type guard based on a.b is None
or a.b is not None
patterns where b
is a member variable that distinguishes two different classes. (#3273)
Co-authored-by: Eric Traut <erictr@microsoft.com>
This commit is contained in:
parent
dc153cb35d
commit
8660a6f870
@ -171,6 +171,7 @@ In addition to assignment-based type narrowing, Pyright supports the following t
|
||||
* `type(x) is T` and `type(x) is not T`
|
||||
* `x is E` and `x is not E` (where E is a literal enum or bool)
|
||||
* `x == L` and `x != L` (where L is a literal expression)
|
||||
* `x.y is None` and `x.y is not None` (where x is a type that is distinguished by a field with a None)
|
||||
* `x.y is E` and `x.y is not E` (where E is a literal enum or bool and x is a type that is distinguished by a field with a literal type)
|
||||
* `x.y == L` and `x.y != L` (where L is a literal expression and x is a type that is distinguished by a field with a literal type)
|
||||
* `x[K] == V` and `x[K] != V` (where K and V are literal expressions and x is a type that is distinguished by a TypedDict field with a literal type)
|
||||
|
@ -70,6 +70,8 @@ import {
|
||||
getTypeVarScopeId,
|
||||
isLiteralType,
|
||||
isLiteralTypeOrUnion,
|
||||
isMaybeDescriptorInstance,
|
||||
isProperty,
|
||||
isTupleClass,
|
||||
isUnboundedTupleClass,
|
||||
lookUpClassMember,
|
||||
@ -321,7 +323,7 @@ export function getTypeNarrowingCallback(
|
||||
const memberName = testExpression.leftExpression.memberName;
|
||||
if (isClassInstance(rightType) && rightType.literalValue !== undefined) {
|
||||
return (type: Type) => {
|
||||
return narrowTypeForDiscriminatedFieldComparison(
|
||||
return narrowTypeForDiscriminatedLiteralFieldComparison(
|
||||
evaluator,
|
||||
type,
|
||||
memberName.value,
|
||||
@ -346,7 +348,7 @@ export function getTypeNarrowingCallback(
|
||||
rightType.literalValue !== undefined
|
||||
) {
|
||||
return (type: Type) => {
|
||||
return narrowTypeForDiscriminatedFieldComparison(
|
||||
return narrowTypeForDiscriminatedLiteralFieldComparison(
|
||||
evaluator,
|
||||
type,
|
||||
memberName.value,
|
||||
@ -356,6 +358,25 @@ export function getTypeNarrowingCallback(
|
||||
};
|
||||
}
|
||||
}
|
||||
|
||||
// Look for X.Y is None or X.Y is not None
|
||||
// These are commonly-used patterns used in control flow.
|
||||
if (
|
||||
testExpression.leftExpression.nodeType === ParseNodeType.MemberAccess &&
|
||||
ParseTreeUtils.isMatchingExpression(reference, testExpression.leftExpression.leftExpression) &&
|
||||
testExpression.rightExpression.nodeType === ParseNodeType.Constant &&
|
||||
testExpression.rightExpression.constType === KeywordType.None
|
||||
) {
|
||||
const memberName = testExpression.leftExpression.memberName;
|
||||
return (type: Type) => {
|
||||
return narrowTypeForDiscriminatedFieldNoneComparison(
|
||||
evaluator,
|
||||
type,
|
||||
memberName.value,
|
||||
adjIsPositiveTest
|
||||
);
|
||||
};
|
||||
}
|
||||
}
|
||||
|
||||
if (testExpression.operator === OperatorType.In) {
|
||||
@ -1423,7 +1444,7 @@ function narrowTypeForDiscriminatedTupleComparison(
|
||||
// Attempts to narrow a type based on a comparison (equal or not equal)
|
||||
// between a discriminating field that has a declared literal type to a
|
||||
// literal value.
|
||||
function narrowTypeForDiscriminatedFieldComparison(
|
||||
function narrowTypeForDiscriminatedLiteralFieldComparison(
|
||||
evaluator: TypeEvaluator,
|
||||
referenceType: Type,
|
||||
memberName: string,
|
||||
@ -1456,6 +1477,53 @@ function narrowTypeForDiscriminatedFieldComparison(
|
||||
return narrowedType;
|
||||
}
|
||||
|
||||
// Attempts to narrow a type based on a comparison (equal or not equal)
|
||||
// between a discriminating field that has a declared None type to a
|
||||
// None.
|
||||
function narrowTypeForDiscriminatedFieldNoneComparison(
|
||||
evaluator: TypeEvaluator,
|
||||
referenceType: Type,
|
||||
memberName: string,
|
||||
isPositiveTest: boolean
|
||||
): Type {
|
||||
return mapSubtypes(referenceType, (subtype) => {
|
||||
let memberInfo: ClassMember | undefined;
|
||||
if (isClassInstance(subtype)) {
|
||||
memberInfo = lookUpObjectMember(subtype, memberName);
|
||||
} else if (isInstantiableClass(subtype)) {
|
||||
memberInfo = lookUpClassMember(subtype, memberName);
|
||||
}
|
||||
|
||||
if (memberInfo && memberInfo.isTypeDeclared) {
|
||||
const memberType = evaluator.makeTopLevelTypeVarsConcrete(evaluator.getTypeOfMember(memberInfo));
|
||||
let canNarrow = true;
|
||||
|
||||
if (isPositiveTest) {
|
||||
doForEachSubtype(memberType, (memberSubtype) => {
|
||||
memberSubtype = evaluator.makeTopLevelTypeVarsConcrete(memberSubtype);
|
||||
|
||||
// Don't attempt to narrow if the member is a descriptor or property.
|
||||
if (isProperty(memberSubtype) || isMaybeDescriptorInstance(memberSubtype)) {
|
||||
canNarrow = false;
|
||||
}
|
||||
|
||||
if (isAnyOrUnknown(memberSubtype) || isNoneInstance(memberSubtype) || isNever(memberSubtype)) {
|
||||
canNarrow = false;
|
||||
}
|
||||
});
|
||||
} else {
|
||||
canNarrow = isNoneInstance(memberType);
|
||||
}
|
||||
|
||||
if (canNarrow) {
|
||||
return undefined;
|
||||
}
|
||||
}
|
||||
|
||||
return subtype;
|
||||
});
|
||||
}
|
||||
|
||||
// Attempts to narrow a type based on a "type(x) is y" or "type(x) is not y" check.
|
||||
function narrowTypeForTypeIs(type: Type, classType: ClassType, isPositiveTest: boolean) {
|
||||
return mapSubtypes(type, (subtype) => {
|
||||
|
@ -0,0 +1,102 @@
|
||||
# This sample tests the type narrowing case for unions of NamedTuples
|
||||
# where one or more of the entries is tested against type None by attribute.
|
||||
|
||||
from typing import NamedTuple, Optional, Union
|
||||
|
||||
IntFirst = NamedTuple(
|
||||
"IntFirst",
|
||||
[
|
||||
("first", int),
|
||||
("second", None),
|
||||
],
|
||||
)
|
||||
|
||||
StrSecond = NamedTuple(
|
||||
"StrSecond",
|
||||
[
|
||||
("first", None),
|
||||
("second", str),
|
||||
],
|
||||
)
|
||||
|
||||
|
||||
def func1(a: Union[IntFirst, StrSecond]) -> IntFirst:
|
||||
if a.second is None:
|
||||
reveal_type(a, expected_text="IntFirst")
|
||||
return a
|
||||
else:
|
||||
reveal_type(a, expected_text="StrSecond")
|
||||
raise ValueError()
|
||||
|
||||
|
||||
UnionFirst = NamedTuple(
|
||||
"UnionFirst",
|
||||
[
|
||||
("first", Union[None, int]),
|
||||
("second", None),
|
||||
],
|
||||
)
|
||||
|
||||
|
||||
def func2(a: Union[UnionFirst, StrSecond]):
|
||||
if a.first is None:
|
||||
reveal_type(a, expected_text="UnionFirst | StrSecond")
|
||||
else:
|
||||
reveal_type(a, expected_text="UnionFirst")
|
||||
|
||||
|
||||
class A:
|
||||
@property
|
||||
def prop1(self) -> Optional[int]:
|
||||
...
|
||||
|
||||
member1: None
|
||||
member2: Optional[int]
|
||||
member3: Optional[int]
|
||||
member4: Optional[int]
|
||||
|
||||
|
||||
class B:
|
||||
@property
|
||||
def prop1(self) -> int:
|
||||
...
|
||||
|
||||
member1: int
|
||||
member2: Optional[int]
|
||||
member3: None
|
||||
member4: int
|
||||
|
||||
|
||||
def func3(c: Union[A, B]):
|
||||
if c.prop1 is None:
|
||||
reveal_type(c, expected_text="A | B")
|
||||
else:
|
||||
reveal_type(c, expected_text="A | B")
|
||||
|
||||
|
||||
def func4(c: Union[A, B]):
|
||||
if c.member1 is None:
|
||||
reveal_type(c, expected_text="A")
|
||||
else:
|
||||
reveal_type(c, expected_text="B")
|
||||
|
||||
|
||||
def func5(c: Union[A, B]):
|
||||
if c.member2 is None:
|
||||
reveal_type(c, expected_text="A | B")
|
||||
else:
|
||||
reveal_type(c, expected_text="A | B")
|
||||
|
||||
|
||||
def func6(c: Union[A, B]):
|
||||
if c.member3 is not None:
|
||||
reveal_type(c, expected_text="A")
|
||||
else:
|
||||
reveal_type(c, expected_text="A | B")
|
||||
|
||||
|
||||
def func7(c: Union[A, B]):
|
||||
if c.member4 is not None:
|
||||
reveal_type(c, expected_text="A | B")
|
||||
else:
|
||||
reveal_type(c, expected_text="A")
|
@ -386,6 +386,12 @@ test('TypeNarrowingLiteralMember1', () => {
|
||||
TestUtils.validateResults(analysisResults, 0);
|
||||
});
|
||||
|
||||
test('TypeNarrowingNoneMember1', () => {
|
||||
const analysisResults = TestUtils.typeAnalyzeSampleFiles(['typeNarrowingNoneMember1.py']);
|
||||
|
||||
TestUtils.validateResults(analysisResults, 0);
|
||||
});
|
||||
|
||||
test('TypeNarrowingTuple1', () => {
|
||||
const analysisResults = TestUtils.typeAnalyzeSampleFiles(['typeNarrowingTuple1.py']);
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user