Memory Leak / Infinite Recursion. TS hangs, TSC never finishes, VSCode and Intellisense dies.

[theonlydaleking]

🔎 Search Terms

Typescript Hangs, Memory Leak, VS Code, Prisma, React-Hook-Form,

🕗 Version & Regression Information

• This is a crash

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about hanging.

Tested on latest 5.2.2 and 5.3.0-dev-20231012. typescript@next

⏯ Playground Link

https://codesandbox.io/p/sandbox/musing-turing-78vp6j?file=%2Fapp%2Fpage.tsx%3A6%2C33

💻 Code

import { useForm } from "react-hook-form";
import { Prisma } from "@prisma/client";

export default function Home() {
 const form = useForm<Prisma.UserCreateInput>();
 ...

This will hang everything. Typescript won't tsc and intellisense will just sit with "loading" no matter what you hover.

meanwhile this works fine:

import { useForm } from "react-hook-form";
import { Prisma } from "@prisma/client";

export default function Home() {
 const form = useForm<>();
 ...

tsc --noEmit --extendedDiagnostics will complete in like 3 seconds with this.

🙁 Actual behavior

Typescript won't complete a tsc --noEmit and intellisense will just sit with "loading" no matter what you hover over. I have seen it once before just set everything to any

With the generated types in the first example - i let it run for 1 hour 59mins on a M1 mac and no output.

You can see the full code example with a minimal repro on the codesandbox link. It also hangs it's intellisense in CSB and won't tsc.
CPU also goes to 100% on both local and CSB

🙂 Expected behavior

Doesn't hang typescript, operates just like if you put any other type in there say

type SomeType = {name: string} 
const form = useForm<SomeType>() 

Additional information about the issue

Another report by someone else here:

https://stackoverflow.com/questions/76932600/high-cpu-usage-when-using-some-prisma-types-with-react-hook-form

It seems to be anything that comes off the Prisma.* types

[Pyrolistical]

I found the provided codesandbox hard to use as the generated prisma client not included. I've extracted the generated client and put it into .app/client

Also to note, the repo description in this issue is incomplete. A call to form.register is required for tsc to stall.

Here is a much smaller repo https://github.com/Pyrolistical/typescript-repo-56081

npm run build never completes.

I started to cut down app/client/index.d.ts, but I gave up after seeing how complicated it is. Also as I cut it down, I noticed tsc does complete. So the extremely recursively types is just really hard for tsc process.

[PranavSenthilnathan]

Thanks, I was able to repro this. It does look like the prisma generated types have complex template strings so tsc is spending a lot of time in removeStringLiteralsMatchedByTemplateLiterals and GC. I'll take a look into if we can cut off computation earlier and/or make the checking smarter.

[PranavSenthilnathan]

Repro without library dependencies (I think the react-hook-form types can be simplified more, but this is a good point for me to start investigating from). Prisma generates deeply nested types with a depth of 10+ and branching at each node from 0 to 6+ (not a balanced tree). Still, the type below roughly approximates that and has the same perf issue.

declare var check : Check<t7>;
check("x.y.z.x.y.z.42");

type rec<t> = t | { [K in 'x' | 'y' | 'z' ]? : t }

type t1 = number[]
type t2 = rec<t1>
type t3 = rec<t2>
type t4 = rec<t3>
type t5 = rec<t4>
type t6 = rec<t5>
type t7 = rec<t6>
type t8 = rec<t7>
type t9 = rec<t8>

// From npm package 'react-hook-form'
type Primitive = number;
type ArrayKey = number;
type IsEqual<T1, T2> = T1 extends T2 ? (<G>() => G extends T1 ? 1 : 2) extends <G>() => G extends T2 ? 1 : 2 ? true : false : false;
type AnyIsEqual<T1, T2> = T1 extends T2 ? IsEqual<T1, T2> extends true ? true : never : never;

type PathImpl<K extends string | number, V, TraversedTypes> = V extends Primitive ? `${K}` : true extends AnyIsEqual<TraversedTypes, V> ? `${K}` : `${K}` | `${K}.${PathInternal<V, TraversedTypes | V>}`;
type PathInternal<T, TraversedTypes = T> = T extends ReadonlyArray<infer V> ? PathImpl<ArrayKey, V, TraversedTypes> : {
 [K in keyof T]-?: PathImpl<K & string, T[K], TraversedTypes>;
}[keyof T];

type Path<T> = T extends any ? PathInternal<T> : never;
type FieldPath<TFieldValues extends FieldValues> = Path<TFieldValues>;
type FieldValues = Record<string, any>;
type Check<TFieldValues extends FieldValues> = <TFieldName extends FieldPath<TFieldValues>>(name: TFieldName) => any;

Some stats (for Check<t7>, Check<t8> and Check<t9> respectively):

> npx tsc 
Types: 2961
Instantiations: 14289
Memory used: 65308K
Check time: 0.33s
Total time: 0.71s
> npx tsc
Types: 7666
Instantiations: 29755
Memory used: 79697K
Check time: 2.12s
Total time: 2.49s
> npx tsc
Types: 21439
Instantiations: 63291
Memory used: 82899K
Check time: 20.45s
Total time: 20.83s

[jakebailey]

Does this bisect to #48044? (https://www.npmjs.com/package/every-ts may be helpful to check, too)

also #52345

[PranavSenthilnathan]

It's this PR which introduces string literal and template literal reduction in unions (every-ts did help 🙂): #41276

[jonahallibone]

Is there any movement on this by chance? I also manage to kill TS with react-hook-form and recursive type definitions