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Avoid infinite recursion with inferReverseMappedType #57837

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Merged
merged 5 commits into from
Apr 16, 2024
Merged

Avoid infinite recursion with inferReverseMappedType #57837

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700da65
track deeply nested types in inferReverseMappedType
gabritto Mar 18, 2024
36e7e06
add caching to inferReverseMappedType
gabritto Mar 22, 2024
698335b
remove obsolete circularity detection; propagate undefined return
gabritto Apr 10, 2024
9b470ec
Merge branch 'main' into gabritto/issue57786
gabritto Apr 10, 2024
719e6c0
fix baselines
gabritto Apr 10, 2024
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24 changes: 23 additions & 1 deletion src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2241,6 +2241,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
var potentialReflectCollisions: Node[] = [];
var potentialUnusedRenamedBindingElementsInTypes: BindingElement[] = [];
var awaitedTypeStack: number[] = [];
var reverseMappedSourceStack: Type[] = [];
var reverseMappedTargetStack: Type[] = [];
var reverseExpandingFlags = ExpandingFlags.None;

var diagnostics = createDiagnosticCollection();
var suggestionDiagnostics = createDiagnosticCollection();
Expand Down Expand Up @@ -25299,14 +25302,33 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
return links.type;
}

function inferReverseMappedType(sourceType: Type, target: MappedType, constraint: IndexType): Type {
function inferReverseMappedTypeWorker(sourceType: Type, target: MappedType, constraint: IndexType): Type {
const typeParameter = getIndexedAccessType(constraint.type, getTypeParameterFromMappedType(target)) as TypeParameter;
const templateType = getTemplateTypeFromMappedType(target);
const inference = createInferenceInfo(typeParameter);
inferTypes([inference], sourceType, templateType);
return getTypeFromInference(inference) || unknownType;
}

function inferReverseMappedType(source: Type, target: MappedType, constraint: IndexType): Type {
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@weswigham weswigham Mar 21, 2024

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Should we cache the results inside this, so we guarantee deeply nested results get cached? Of the callers of this function, only getTypeOfReverseMappedSymbol currently caches - the other uses don't (directly) cache the result, so could, in theory, witness different results for the same set of input types at different points. You can probably only easily trigger such a behavior with a reverse mapped type over an array...? Maybe?

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@gabritto gabritto Mar 22, 2024

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I was adding the cache to inferReverseMappedType and looking at inferTypeForHomomorphicMappedType. I'm now wondering: could I do away with the recursion detection in inferTypeForHomomorphicMappedType (that uses homomorphicMappedTypeInferenceStack)?

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@gabritto gabritto Mar 22, 2024

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I'm pretty sure that we can, however this once again begs the question of what to return when we find a circularity. inferTypeForHomomorphicMappedType returns undefined in this case. I'll have to think some more about this, but I'm planning on removing that circularity detection code in inferTypeForHomomorphicMappedType.

reverseMappedSourceStack.push(source);
reverseMappedTargetStack.push(target);
const saveExpandingFlags = reverseExpandingFlags;
if (isDeeplyNestedType(source, reverseMappedSourceStack, reverseMappedSourceStack.length, 2)) reverseExpandingFlags |= ExpandingFlags.Source;
if (isDeeplyNestedType(target, reverseMappedTargetStack, reverseMappedTargetStack.length, 2)) reverseExpandingFlags |= ExpandingFlags.Target;
let type;
if (reverseExpandingFlags !== ExpandingFlags.Both) {
type = inferReverseMappedTypeWorker(source, target, constraint);
}
else {
type = unknownType;
}
reverseMappedSourceStack.pop();
reverseMappedTargetStack.pop();
reverseExpandingFlags = saveExpandingFlags;
return type;
}

function* getUnmatchedProperties(source: Type, target: Type, requireOptionalProperties: boolean, matchDiscriminantProperties: boolean): IterableIterator<Symbol> {
const properties = getPropertiesOfType(target);
for (const targetProp of properties) {
Expand Down
6 changes: 3 additions & 3 deletions tests/baselines/reference/mappedTypeRecursiveInference.types
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Expand Up @@ -3,9 +3,9 @@
=== Performance Stats ===
Strict subtype cache: 300 / 300 (nearest 100)
Assignability cache: 5,000 / 5,000 (nearest 100)
Type Count: 15,000 / 15,000 (nearest 100)
Instantiation count: 486,000 / 503,500 (nearest 500)
Symbol count: 174,500 / 177,000 (nearest 500)
Type Count: 14,700 / 14,800 (nearest 100)
Instantiation count: 483,000 / 501,000 (nearest 500)
Symbol count: 174,000 / 176,500 (nearest 500)

=== mappedTypeRecursiveInference.ts ===
interface A { a: A }
Expand Down
28 changes: 28 additions & 0 deletions tests/baselines/reference/reverseMappedTypeRecursiveInference.js
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@@ -0,0 +1,28 @@
//// [tests/cases/compiler/reverseMappedTypeRecursiveInference.ts] ////

//// [reverseMappedTypeRecursiveInference.ts]
type Foo<V> = {
[K in keyof V]: Foo<V[K]>;
}

type Bar<V> = {
[K in keyof V]: V[K] extends object ? Bar<V[K]> : string;
}

function test<V>(value: Foo<V>): V {
console.log(value);
return undefined as any;
}

const bar: Bar<any> = {};

test(bar);

//// [reverseMappedTypeRecursiveInference.js]
"use strict";
function test(value) {
console.log(value);
return undefined;
}
var bar = {};
test(bar);
55 changes: 55 additions & 0 deletions tests/baselines/reference/reverseMappedTypeRecursiveInference.symbols
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@@ -0,0 +1,55 @@
//// [tests/cases/compiler/reverseMappedTypeRecursiveInference.ts] ////

=== reverseMappedTypeRecursiveInference.ts ===
type Foo<V> = {
>Foo : Symbol(Foo, Decl(reverseMappedTypeRecursiveInference.ts, 0, 0))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 0, 9))

[K in keyof V]: Foo<V[K]>;
>K : Symbol(K, Decl(reverseMappedTypeRecursiveInference.ts, 1, 5))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 0, 9))
>Foo : Symbol(Foo, Decl(reverseMappedTypeRecursiveInference.ts, 0, 0))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 0, 9))
>K : Symbol(K, Decl(reverseMappedTypeRecursiveInference.ts, 1, 5))
}

type Bar<V> = {
>Bar : Symbol(Bar, Decl(reverseMappedTypeRecursiveInference.ts, 2, 1))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 4, 9))

[K in keyof V]: V[K] extends object ? Bar<V[K]> : string;
>K : Symbol(K, Decl(reverseMappedTypeRecursiveInference.ts, 5, 5))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 4, 9))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 4, 9))
>K : Symbol(K, Decl(reverseMappedTypeRecursiveInference.ts, 5, 5))
>Bar : Symbol(Bar, Decl(reverseMappedTypeRecursiveInference.ts, 2, 1))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 4, 9))
>K : Symbol(K, Decl(reverseMappedTypeRecursiveInference.ts, 5, 5))
}

function test<V>(value: Foo<V>): V {
>test : Symbol(test, Decl(reverseMappedTypeRecursiveInference.ts, 6, 1))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 8, 14))
>value : Symbol(value, Decl(reverseMappedTypeRecursiveInference.ts, 8, 17))
>Foo : Symbol(Foo, Decl(reverseMappedTypeRecursiveInference.ts, 0, 0))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 8, 14))
>V : Symbol(V, Decl(reverseMappedTypeRecursiveInference.ts, 8, 14))

console.log(value);
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>value : Symbol(value, Decl(reverseMappedTypeRecursiveInference.ts, 8, 17))

return undefined as any;
>undefined : Symbol(undefined)
}

const bar: Bar<any> = {};
>bar : Symbol(bar, Decl(reverseMappedTypeRecursiveInference.ts, 13, 5))
>Bar : Symbol(Bar, Decl(reverseMappedTypeRecursiveInference.ts, 2, 1))

test(bar);
>test : Symbol(test, Decl(reverseMappedTypeRecursiveInference.ts, 6, 1))
>bar : Symbol(bar, Decl(reverseMappedTypeRecursiveInference.ts, 13, 5))

40 changes: 40 additions & 0 deletions tests/baselines/reference/reverseMappedTypeRecursiveInference.types
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@@ -0,0 +1,40 @@
//// [tests/cases/compiler/reverseMappedTypeRecursiveInference.ts] ////

=== reverseMappedTypeRecursiveInference.ts ===
type Foo<V> = {
>Foo : Foo<V>

[K in keyof V]: Foo<V[K]>;
}

type Bar<V> = {
>Bar : Bar<V>

[K in keyof V]: V[K] extends object ? Bar<V[K]> : string;
}

function test<V>(value: Foo<V>): V {
>test : <V>(value: Foo<V>) => V
>value : Foo<V>

console.log(value);
>console.log(value) : void
>console.log : (...data: any[]) => void
>console : Console
>log : (...data: any[]) => void
>value : Foo<V>

return undefined as any;
>undefined as any : any
>undefined : undefined
}

const bar: Bar<any> = {};
>bar : Bar<any>
>{} : {}

test(bar);
>test(bar) : { [x: string]: any; }
>test : <V>(value: Foo<V>) => V
>bar : Bar<any>

18 changes: 18 additions & 0 deletions tests/cases/compiler/reverseMappedTypeRecursiveInference.ts
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@@ -0,0 +1,18 @@
// @strict: true

type Foo<V> = {
[K in keyof V]: Foo<V[K]>;
}

type Bar<V> = {
[K in keyof V]: V[K] extends object ? Bar<V[K]> : string;
}

function test<V>(value: Foo<V>): V {
console.log(value);
return undefined as any;
}

const bar: Bar<any> = {};

test(bar);