Deep mocking results in a TypeScript error + extreme compilation slowness

[mklopets]

Deep mocking results in a TypeScript error + extreme compilation slowness

[marchaos]

I'll try and get a fix for this, without breaking the functionality that added to the slowness.

[marchaos]

Fixed in 3.0.0

[jnardone]

seeing the same on 2.0.6->2.0.7 (node 16.16, TS 4.7.4)

[zaniluca]

Got the same problem too, for my case it was resolved by downgrading to 2.0.6

• jest: "^28.1.3"
• jest-mock-extended: "2.0.6",
• node: 16.15.1

[atahanozbayram]

I agree I have found the same problem in my repository, using 2.0.4 is fine but 2.0.7 makes typescript compilation from 13 seconds to 630 seconds for me.

[royhadad]

happens to me with versions 2.0.7, 2.0.6, 2.0.4 - any ideas for another fix?

[xenoterracide]

same here

System:

• OS: macOS 11.6.6
• CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz

Binaries:

• Node: 16.14.2 - /private/var/folders/xk/s3n8ww014pzbx2sn30ctz7000000gq/T/xfs-0e6f078f/node
• Yarn: 3.2.1 - /private/var/folders/xk/s3n8ww014pzbx2sn30ctz7000000gq/T/xfs-0e6f078f/yarn
• npm: 8.5.0 - ~/.asdf/plugins/nodejs/shims/npm

❯ yarn why typescript
├─ @cof/e1-devexchange-client@workspace:packages/devexchange-client
│  └─ typescript@patch:typescript@npm%3A4.7.4#~builtin<compat/typescript>::version=4.7.4&hash=7ad353 (via patch:typescript@^4.7.4#~builtin<compat/typescript>)

[roblframpton]

I am also experiencing this issue, although I am using the regular mock function, not mockDeep. For me the issue is also resolved by downgrading to 2.0.6.

You can see in the tsc tracer that the problem is with the following file, which it spends several minutes processing:

{"pid":1,"tid":1,"ph":"B","cat":"check","ts":9729602.199999848,"name":"checkSourceFile","args":{"path":"/[...]/node_modules/jest-mock-extended/lib/Mock.d.ts"}}

On version 2.0.6 it only takes a short time on this step, but on 2.0.7 it gets stuck.

Environment

Ubuntu 20.04.2 LTS on Windows 10 WSL
Node 16.15.1
npm 8.11.0
tsc version 4.7.4

[wokkaflokka]

Observed this issue attempting to upgrade from 2.0.6 to 2.0.7 (along with painfully long compilation times).

node_modules/jest-mock-extended/lib/Mock.d.ts:27:2781 - error TS2536: Type 'K_1' cannot be used to index type 'T[K]'.

27 export declare const mockDeep: <T>(mockImplementation?: DeepPartial<T> | undefined) => { [K in keyof T]: T[K] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K] extends infer T_1 ? { [K_1 in keyof T_1]: T[K][K_1] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1] extends infer T_2 ? { [K_2 in keyof T_2]: T[K][K_1][K_2] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2] extends infer T_3 ? { [K_3 in keyof T_3]: T[K][K_1][K_2][K_3] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3] extends infer T_4 ? { [K_4 in keyof T_4]: T[K][K_1][K_2][K_3][K_4] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3][K_4] extends infer T_5 ? { [K_5 in keyof T_5]: T[K][K_1][K_2][K_3][K_4][K_5] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3][K_4][K_5] extends infer T_6 ? { [K_6 in keyof T_6]: T[K][K_1][K_2][K_3][K_4][K_5][K_6] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3][K_4][K_5][K_6] extends infer T_7 ? { [K_7 in keyof T_7]: T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7] extends infer T_8 ? { [K_8 in keyof T_8]: T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8] extends infer T_9 ? { [K_9 in keyof T_9]: T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & (T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9] extends infer T_10 ? { [K_10 in keyof T_10]: T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9][K_10] extends (...args: infer A) => infer B ? CalledWithMock<B, A> & any & T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9][K_10] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9][K_10]>; } : never) & T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8][K_9]>; } : never) & T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7][K_8]>; } : never) & T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4][K_5][K_6][K_7]>; } : never) & T[K][K_1][K_2][K_3][K_4][K_5][K_6] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4][K_5][K_6]>; } : never) & T[K][K_1][K_2][K_3][K_4][K_5] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4][K_5]>; } : never) & T[K][K_1][K_2][K_3][K_4] : DeepMockProxy<T[K][K_1][K_2][K_3][K_4]>; } : never) & T[K][K_1][K_2][K_3] : DeepMockProxy<T[K][K_1][K_2][K_3]>; } : never) & T[K][K_1][K_2] : DeepMockProxy<T[K][K_1][K_2]>; } : never) & T[K][K_1] : DeepMockProxy<T[K][K_1]>; } : never) & T[K] : DeepMockProxy<T[K]>; } & T;
     

Environment

Mac 12.4 (Ubuntu 20.04)
Node 16.15.0
npm 8.5.5
tsc version 4.7.4

[marchaos]

I've pushed a fix as version 3.0.0-beta1. This required a small breaking change, but I'd imagine for 99% of users this version should be backwards compatible with 2.0.x. If you were using mockDeep and you were mocking functions that also had props, you will need to use

mockDeep({ funcPropSupport: true });
or 
mockDeep({ funcPropSupport: true }, mockImplementation);

but expect the same performance issue / penalty if you need to use this.

It would be good to get some feedback on this 🙏🏽 . Once there's enough feedback that this issue is fixed, I'll push a 3.0.0